TNT2014 Programme Book and Posters by Phantoms Foundation

Programme & Posters

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TNT2014 index

Foreword

Committees

Poster awards

Sponsors

Exhibitors

Programme

Posters

On behalf of the International, Local and Technical Committees, we take great pleasure in welcoming you to Barcelona (Spain) for the 15th “Trends in NanoTechnology” International Conference (TNT2014).

TNT2014

Foreword

TNT2014 is being held in large part due to the overwhelming success of earlier TNT Nanotechnology Conferences. This high-level scientific meeting series aims to present a broad range of current research in Nanoscience and Nanotechnology worldwide, as well as initiatives such as MANA/NIMS, CIC nanoGUNE, IBEC, DIPC, etc. TNT events have demonstrated that they are particularly effective in transmitting information and promoting interaction and new contacts among workers in this field. Furthermore, this event offers visitors, exhibitors and sponsors an ideal opportunity to interact with each other. This year, a Graphene one-day Symposium will again be organized within TNT2014 in collaboration with ICN2 (Spain). This Graphene Day will entail a plenary session during the morning and the afternoon session will be divided in track A (Graphene science driven contributions & Graphene in Cataluña) and track B (Graphene driven applications Keynotes). One of the main objectives of the Trends in Nanotechnology conference is to provide a platform where young researchers can present their latest work and also interact with high-level scientists. For this purpose, the Organising Committee provides every year around 40 travel

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grants for students. In addition, this year, 7 awards will be given to young PhD students for their contributions presented at TNT. More than 40 senior scientists are involved in the selection process. Grants and awards are funded by the TNT Organisation in collaboration with private bodies and several governmental/research institutions. TNT is now one of the premier European conferences devoted to nanoscale science and technology. We are indebted to the following Scientific Institutions, Companies and Government Agencies for their financial support: Phantoms Foundation, Donostia International Physics Center (DIPC), Universidad Autónoma de Madrid (UAM), ICEX España Exportación e Inversiones, NIMS (Nanomaterials Laboratory) and MANA (International Center for Materials and Nanoarchitectonics), Institute for Bioengineering of Catalonia (IBEC), Institut Català de Nanociencia I Nanotecnologia (ICN2), Materials Physics Center (CFM), FEI, European Physical Society (EPS), DAYFISA and Viajes El Corte Inglés. We would also like to thank the following companies and institutions for their participation: Institut Català de Nanociencia I Nanotecnología (ICN2), Raith Nanofabrication, Keysight Technologies, Scientec Ibérica, Oxford Instruments, WITec, LOT-QuantumDesign, Alava Ingenieros, ICEX España Exportación e Inversiones and Phantoms Foundation. In addition, thanks must be given to the staff of all the organising institutions whose hard work has helped planning this conference.

TNT2014 barcelona (spain)

Organising Committee

TNT2014 TNT2014 barcelona (spain)

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TNT2014 Committees

Organising Committee

Technical Committee

Jose-Maria Alameda (Universidad de Oviedo, Spain) Masakazu Aono (MANA, NIMS, Japan) Robert Baptist (CEA / DRT / LETI, France) Xavier Cartoixa (UAB, Spain) Antonio Correia (Phantoms Foundation, Spain) – Conference Chairman Gianaurelio Cuniberti (TUD, Germany) Pedro Echenique (DICP / UPV, Spain) Jose Maria Gonzalez Calbet (UCM, Spain) Uzi Landman (Georgia Tech, USA) Jose Manuel Perlado Martin (IFN-ETSII / UPM, Spain) Jose Maria Pitarke (CIC nanoGUNE Consolider, Spain) Pablo Ordejon (ICN2, Spain) Ron Reifenberger (Purdue University, USA) Jose Rivas (Santiago de Compostela Univ., Spain) Juan Jose Saenz (UAM, Spain) Josep Samitier (IBEC - Universitat de Barcelona, Spain) Frank Scheffold (University of Fribourg, Switzerland) Didier Tonneau (CNRS-CINaM, France)

Carmen Chacón Tomé (Phantoms Foundation, Spain) Viviana Estêvão (Phantoms Foundation, Spain) Maite Fernández Jiménez (Phantoms Foundation, Spain) Paloma Garcia Escorial (Phantoms Foundation, Spain) Pedro Garcia Mochales (UAM, Spain) Adriana Gil (Spain) Conchi Narros Hernández (Phantoms Foundation, Spain) Joaquin Ramon-Laca (Phantoms Foundation, Spain) Jose-Luis Roldan (Phantoms Foundation, Spain)

International Scientific Committee Masakazu Aono (MANA / NIMS, Japan) Emilio Artacho (CIC nanoGUNE Consolider, Spain) Andreas Berger (CIC nanoGUNE Consolider, Spain) Fernando Briones (IMM / CSIC, Spain) Remi Carminati (Ecole Centrale Paris, France) Jose-Luis Costa Kramer (IMM / CSIC, Spain) Antonio Garcia Martin (IMM / CSIC, Spain) Raquel Gonzalez Arrabal (IFN-ETSII / UPM, Spain) Pierre Legagneux (Thales, France) Annick Loiseau (ONERA - CNRS, France) Stephan Roche (ICN2, Spain) Josep Samitier (IBEC - Universitat de Barcelona, Spain)

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TNT2014 Poster awards

Funded by

Award

European Physical Society

200 Euros

Phantoms Foundation

Tablet

Phantoms Foundation

Tablet

Phantoms Foundation

Tablet

David Prize

Private donation

300 US Dollars

Keren Prize

Private donation

300 US Dollars

TNT 2014 Organisation

TNT2014 barcelona (spain)

Free registration to the 2015 2015 Conference

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TNT2014 Sponsors

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TNT2014 Exhibitors

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Exhibitors

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Raith is a leading precision technology solution provider for nanofabrication, electron beam lithography, focused ion beam fabrication, nanoengineering and reverse engineering applications. Customers include universities and other organizations involved in various fields of nanotechnology research and materials science – as well as industrial and medium sized enterprises that use nanotechnology for specific product applications or produce compound semiconductors. Founded in 1980 and headquartered in Dortmund, Germany, Raith employs more than 200 people. The company works as close as possible with customers in the most important global markets through subsidiaries in the Netherlands, the USA and in Asia and through an extensive partner and service network. Raith GmbH Konrad-Adenauer-Allee 8 44263 Dortmund- Germany Phone: +49 (0)231 / 95004 - 0 Fax: +49 (0)231 / 95004 - 460 Web: www.raith.com

ScienTec Ibérica, is the spanish branch of ScienTec France, its mission is to serve and attend the Iberian Nano-micro surface analysis market from its office in Madrid. Its field of activity is related to scientific research, R&D and industrial metrology. In terms of product line, we deal with atomic force microscopes, contact profilometry, digital holography, interferometry, nanoindentation, filmetrics and high aspect ratio confocals. ScienTec Ibérica accompanies you in your various projects by offering system adapted to your applications (nanotechnology, polymer, material surfaces, biology, semiconductor, microfabricaiton and the cutting tool industry…) ScienTec Ibérica C/ Rufino Sánchez 83 28290 Las Rozas (Madrid) Phone: 91-8429467 Fax: 902-875572 info@scientec.es Web: www.scientec.es

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The Institut Català de Nanociència i Nanotecnologia (ICN2) focuses on the newly discovered physical and chemical properties that arise from the fascinating behaviour of matter at the nanoscale. The Mission of ICN2 is to achieve scientific and technological excellence in nanoscience and nanotechnology, and to facilitate the adoption and integration of nanotechnologies into society and industry. The patrons of ICN2 are the Government of Catalonia (Generalitat), the Consejo Superior de Investigaciones Científicas (CSIC), and the Autonomous University of Barcelona (UAB). The Institute promotes collaboration among scientists from diverse backgrounds (physics, chemistry, biology, and engineering) to develop basic and applied research, always seeking interactions with local and global industry. ICN2 also trains researchers in nanotechnology, develops numerous activities to facilitate the uptake of nanotechnology by industry, and promotes networking among scientists, engineers, technicians, business people, society, and policy makers. ICN2 was accredited in 2014 by the Spanish Ministry of Economy and Competitiveness as a Severo Ochoa Centre of Excellence, the highest recognition of centres of excellence in Spain. The ICN2 proposal for this call focused on the development of nanoscale devices that are effective and marketable. Based on scientific advances in the development of materials, nanofabrication, characterisation, and theoretical simulation, practical applications will be developed in three main areas: Biosystems, Energy, and Information technology and telecommunications. Web: www.icn.cat

Keysight Technolgies (formerly Agilent Technologies) is your one-stop shop for your research instrumentation. We will show the new 7500 AFM which features atomic resolution imaging with a 90um closed-loop scanner , the industry’s leading built in environmental chamber and exceptional temperature control. Keysight will introduce the 8500B FE SEM, a compact, high performance SEM now with the option of EDS elemental analysis. Combining low voltage imaging & advanced EDS elemental analysis, the 8500B is the perfect lab companion. Whatever your application we have the instrument you need for your research. Keysight Technologies Web:www.keysight.com

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Exhibitors WITec GmbH (Headquarters) Lise-Meitner-Str. 6 89081 Ulm, Germany Tel: +49 (0)731 14070-0 Fax: +49 (0)731 14070-200 Web: www.WITec.de

LOT-QuantumDesign specialises in supplying highquality components and leading edge instrumentation to the academic community and R&D market. LOTQuantumDesign staff have expertise in applications in materials characterization, thin film analysis, special cameras and imaging, spectroscopy, photonics and bioand nanotechnology. A dedicated team of more than 120 people in over 10 countries, supported by state of the art infrastructure, provides fast, flexible and reliable service to customers and partners. At this exhibition LOT-QuantumDesign focuses on displaying products from the branch of magnetism and cryotechnology, including Quantum Designs PPMS and MPMS, and a closed-cycle optical cryostats from Montana Instruments, called the Cryostation. We will also be happy to establish a contact to our other product specialists, who are responsible for the above mentioned application areas.

Alava Ingenieros Group is an entirely privately owned group which has been providing high technology solutions in the Testing, Measurement, Communications, Security, Defence and Preventive Maintenance fields since it was first founded in 1973 and recently in Nanotechnology. The equipments that are provided from The Nanotechnology Systems Division of Alava Ingenieros are the following: • LVEM5 (Delong America), the only benchtop electron microscope with SEM, STEM and TEM capabilities. • 85000 FE-SEM (Keysight) a compact system that offers researchers a field emission scanning electron microscope right in their own laboratory. • S neox (Sensofar), the non-contact optical 3D profiling. S neox outperforms all existing optical profilers, combining confocal, interferometry and focus variation techniques in the same sensor head without any moving parts. • 5500 & 7500 AFM (Keysight), wide range of highprecision atomic force microscopes that are highly configurable. • NanoIR (Anays Instruments), this tool reveals the chemical composition of samples at the nanoscale combining both nanoscale IR spectroscopy and atomic force microscopy. In addition, the nanoIR system provides high-resolution characterization of local topographic, mechanical, and thermal properties. • G200 NanoIndenter (Keysight), the most accurate, flexible, user-friendly instrument for nanomechanical testing. • Glovebox Workstations (MBraun) that can be equipped with a comprehensive set of optional features for the research and development of emerging technologies, like PVD or ALD. The group not only offers high technology distribution but also consultancy, engineering, training and technical services, providing turn-key projects. Alava Ingenieros excels in its ability to adapt to the specific needs of its customers and its responsible attitude towards supplies and services carried out, all of which is backed by solid international partnerships and in house resources for integration, installation and after-sales technical service. Web: www.alavaingenieros.com

Web: www.lot-qd.com

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TNT2014

WITec GmbH is a manufacturer of high-resolution optical and scanning probe microscopy solutions for scientific and industrial applications: • Scanning Near-field optical Microscopy (SNOM or NSOM) • Atomic Force Microscopy (AFM) • Confocal Microscopy • Raman Microscopy (Ultrasensitive and fast Raman Imaging) Focusing on innovations and constantly introducing new technologies, we are the leading experts for your optical, structural and chemical imaging tasks.

Exhibitors

TNT2014

Omicron NanoScience is the world's leading supplier of analytical instrumentation solutions in nanotechnology research and development. With a team of more than 300 specialists we provide for: • Cryogenic Systems (e.g. Optical & Spectroscopy Cryostats, Helium-3 & Dilution refrigerators) • Electron Spectroscopy (e.g. XPS systems, Spectrometers, LEED, PEEM instruments) • Scanning Probe Microscopy (e.g. our SPM’s for Low-, Room-, and Variable Temperature) • Superconducting Magnets (e.g. Superconducting Solenoids, Ultra-High-Field-, Vector-rotate or custom magnets, Magneto-optical systems) • Thin Film & Tailored Systems (e.g. our MBE series PRO, EVO and Lab) • Service & Engineering Oxford Instruments Omicron NanoScience Limburger Str. 75 D-65232 Taunusstein, Germany Tel: +49(0) 6128 / 987 – 0 Fax: +49(0) 6128 / 987 – 185 omicron.nanoscience@oxinst.com Web: www.oxford-instruments.com

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ICEX Spain Trade and Investment is the Spanish Government Agency serving Spanish companies to promote their exports and facilitate their international expansion, assisted by the network of Spanish Embassy’s Economic and Commercial Offices. Web: www.icex.es

Phantoms Foundation, based in Madrid, is a non-profit organization which focus its activities on Nanoscience & Nanotechnology (N&N), bringing together and coordinating the efforts of Spanish and European universities groups, research institutes and companies through the organization of major scientific and technological networks and events, such as ImagineNano or Graphene. Today, the Phantoms Foundation is a key player in structuring and promoting European excellence and improving collaborations in N&N. It is also essential as a platform for spreading excellence on funded projects and for establishing new networks of collaboration. Web: www.phantomsnet.net

TNT2014 barcelona (spain)

TNT2014 Programme Monday – October 27, 2014 08:00-08:45

REGISTRATION

08:45-09:00

TNT2014 Opening Ceremony - Welcome and Introduction

09:00-09:30

Uzi Landman (Georgia Tech, USA)

"Adventures in nanoscale computational microscopy"

09:30-10:00

Romain Quidant (ICFO & ICREA, Spain) "Thermoplasmonics: Nanoscale control of heat and its applications"

10:00-10:30

Rainer Hillenbrand (CIC nanoGUNE, Spain) "Two-Dimensional Optics with Graphene Plasmons Launched by Metal Antennas"

10:30-11:00

Frank Koppens (ICFO, Spain) "Electrical control and detection of nanoscale optical fields with 2d materials"

11:00-11:30

Laura M. Lechuga (ICN2 & CSICruiz, Spain) "Nanophotonic lab-on-chip biosensors for point-of-care diagnostics"

11:30-12:00 12:00-12:30

Francisco J. Meseguer (UPV & ICMM-CSIC, Spain) Lluis F. Marsal (Universitat Rovira i Virgili, Spain) "Nanostructural engineering of nanoporous anodic alumina for optical biosensing"

13:00-13:15

Martin Schnell (CIC nanoGUNE, Spain) "Synthetic Optical Holography for Rapid Optical Nanoimaging"

13:15-13:30

Alexander Govyadinov (CIC nanoGUNE, Spain) "Recovery of Permittivity and Depth from Near-Field Data as a Step toward Infrared Nanotomography"

13:30-15:00

Cocktail Lunch (offered by TNT2014) Poster Session - Instrument Exhibition

15:00-19:00

PLENARY SESSION

14:00-16:00

K K K

Coffee Break - Poster Session - Instrument Exhibition "Silicon colloids. Properties and applications to metamaterials, sensing and solar energy harvesting"

12:30-13:00

K K O O

PARALLEL SESSION: FLAG-ERA Graphene Networking Event PLENARY SESSION Joaquin Fernández Rossier (INL, Portugal)

"Spintronics at the atomic scale: the quantum frontier"

15:30-15:45

Lluís Balcells (ICAMB-CSIC, Spain) "Unexpected high conductivity at twin boundaries in LSMO thin films"

15:45-16:00

Konstantin Gusliyenko (UPV/EHU & IKERBASQUE, Spain) "Microwave absorption properties of two dimensional arrays of permalloy nanodots in the vortex and quasi-uniform ground states"

16:00-16:15

Sergio Tatay (Universitat de València, Spain) "Growth of Self-Assembled Monolayers directly on a ferromagnetic metal surface"

16:15-17:15 17:15-17:45

Daniel Sanchez Portal (CFM-UPV/EHU & DIPC, Spain) Xavier Blase (Institut Néel, CNRS & UFJ, France) "Excited states in organic systems from many-body-perturbation theory: the FIESTA initiative"

18:15-18:45

Mads Brandbyge (Technical University of Denmark, Denmark) "Elastic and inelastic electron transport simulations from first principles – new methods and effects"

18:45-19:00

O O

Coffee Break - Poster Session - Instrument Exhibition "Simulations of Electron Dynamics in Solids and Nanostructures with SIESTA"

17:45-18:15

Mathias P. Ljungberg (Donostia International Physics Center, Spain) "Optical spectra and quasiparticle energies of molecules using a local basis"

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Programme

TNT2014

Monday â&#x20AC;&#x201C; October 27, 2014 PARALLEL SESSION: FLAG-ERA Graphene Networking Event 09:00-13:30

REGISTRATION (free of charge)

13:30-14:30

Cocktail Lunch (offered by FLAG-ERA) Beginning of Networking Event

14:30-14:45

Jari Kinaret (Graphene Flagship Scientific Coordinator) The Graphene Flagship

"Introduction to the Graphene Flagship initiative"

14:45-15:00

Edouard Geoffrois (FLAG-ERA Coordinator) FLAG-ERA, the Flagship ERA-NET

"Introduction to the objetives and activities of FLAG-ERA"

15:00-15:15

Anabela Isidro (FLAG-ERA Joint Transnational Call Coordinator) The FLAG-ERA Joint Transnational Call

"Call participating countries, rules and modalities"

15:15-15:30

Q&A

15:30

Flash Presentations Informal Posters Discussion + Happy Hour End of Networking Event

K: Keynote / I: Invited / O: Orals

18:00

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09:00-09:30

Jose A. Garrido (Technische Universität München, Germany) "Graphene field effect transistors for biosensing and bioelectronics"

09:30-09:45

Nieves Casañ-Pastor (ICMAB-CSIC, Spain) "Electrochemical production of graphene and of Carbon nanotubes or Graphene hybrids with Iridium Oxide. Coatings and electrodes for the Neural System"

09:45-10:15

Erik Dujardin (CEMES/CNRS, France) "Graphene as an integrated platform for molecular-scale devices"

10:15-10:30

Antonio J. Martínez Galera (UAM, Spain & Universität zu Köln, Germany) "Graphene Nanopatterning at the Nanometer Scale"

10:30-10:45

Neeraj Mishra (Istituto Italiano di Tecnologia, Italy) "A study on the growth of graphene on h-BN by chemical vapor deposition"

10:45-11:30 11:30-11:35

Edouard Geoffrois (FLAG-ERA Coordinator, France) Samindranath Mitra (Physical Review Letters, USA) "Graphene in PRL"

11:50-12:20

Kostas Kostarelos (University of Manchester, UK) "Adoption of graphene materials in medicine"

12:20-12:35

Klaas-Jan Tielrooij (Institut de Ciéncies Fotóniques, Spain) "Ultrafast and efficient photo-induced electron heating in graphene"

12:35-12:50 12:50-13:05

Mikhail Fistu (Ruhr-Universität Bochum, Germany) "Radiation-induced coherent quantum phenomena in the transport of graphene based n-p and n-p-n junctions"

Vladimir Falko (Lancaster University, UK) "Anomalous sequence of quantum Hall liquids revealing tunable Lifshitz transition in bilayer graphene"

13:05-13:20

O K

Programme

O O

Coffee Break - Poster Session - Instrument Exhibition "Introduction to the objectives and activities of FLAG-ERA, the Flagship ERA-NET"

11:35-11:50

TNT2014

Tuesday – October 28, 2014

Graphene day

Wolfgang Belzig (University of Konstanz, Germany) "Ground state cooling of a carbon nano-mechanical resonator using spin-polarized current"

13:20-15:00

O O K O O O O

Lunch PARALLEL SESSION (INDUSTRY) - GRAPHENE TRACK A

15:00-19:10

K: Keynote / I: Invited / O: Orals

PARALLEL SESSION (GRAPHENE IN CATALUÑA) - GRAPHENE TRACK B

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Programme

TNT2014

Tuesday – October 28, 2014 PARALLEL SESSION (INDUSTRY) - GRAPHENE TRACK A 15:00-15:30

Günther Ruhl (Infineon Technologies AG, Germany) "Perspectives of Graphene in Semiconductor Industry"

15:30-16:00

Michael D. Patterson (Graphene Frontiers, USA) "Graphene Biosensors - The Next Frontier in Medical Diagnostics"

16:00-16:30

Max Lemme (University of Siegen, Germany) "Graphene in Microelectronics - It's not all about Mobility!"

16:30-17:10 17:10-17:40

Amaia Zurutuza (Graphenea S.A., Spain) Karlheinz Strobl (CVD Equipment Corporation, USA) "CVD graphene: Batch versus Roll to Roll Scale-up"

18:10-18:40

Gonçalo Gonçalves (Aixtron Ltd., UK) Elena Bailo (WITec GmbH, Germany) "Visualizing Carbon Material Properties at Highest Performance and Resolution Using Confocal Raman, AFM, SNOM and SEM"

18:55-19:10

K K K

"Recent advances in CVD graphene"

18:40-18:55

Coffee Break - Poster Session - Instrument Exhibition "Progress in Graphene Materials Applications"

17:40-18:10

Elisabet Prats-Alfonso (IMB-CNM / CSIC & CIBER-BBN, Spain) "Validation of graphene-based devices for neurophysiological recordings"

O O

PARALLEL SESSION (GRAPHENE IN CATALUÑA) - GRAPHENE TRACK B 15:00-15:20

David Jiménez (Universitat Autònoma de Barcelona, Spain) "Detrimental factors lowering the performance of graphene field-effect transistors"

15:20-15:40

Arben Merkoçi (ICN2 & ICREA, Spain) "Graphene-based platforms for electrical and optical biosensing"

15:40-16:00

Valerio Pruneri (ICFO, Spain) "Ultrathin metals and graphene for flexible optoelectronic devices"

16:00-16:20

Nuria Ferrer-Anglada (Universitat Politècnica de Catalunya, Spain) "Stable p-doping in graphene and Terahertz spectroscopy"

16:20-16:35

Jose Eduardo Barrios-Vargas (ICN2, Spain) "Polycrystalline graphene as a raw material for gas sensors"

K: Keynote / I: Invited / O: Orals

16:35-17:10 17:10-17:30

Philippe Godignon (CNM-ICMAB-CSIC, Spain) Xavier Cartoixà (Universitat Autònoma de Barcelona, Spain) "Contact resistance in metal/two-dimensional material junctions from first principles"

17:45-18:00

Wlodzimierz Jaskolski (Nicolaus Copernicus University, Poland) "Theory of the electronic structure of grain boundaries in graphene"

18:00-18:15

Raúl Rengel (Universidad de Salamanca, Spain) "Impact of the Temperature and Remote Phonon Scattering on Charge Transport in Supported Graphene"

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I I O

I O O

Nicolas Leconte (ICN2, Spain) "Quantum transport in chemically functionalized graphene at high magnetic field: Defect-Induced Critical States and Breakdown of Electron-Hole Symmetry"

18:15-18:30

Coffee Break - Poster Session - Instrument Exhibition "Challenges in nano-patterning of epitaxial graphene grown on Silicon Carbide wafers"

17:30-17:45

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TNT2014 barcelona (spain)

09:00-09:30

Christoph Strunk (University of Regensburg, Germany) "Discrete symmetries and the Kondo Effect in Clean Carbon Nanotubes"

09:30-10:00

Adrian Bachtold (ICFO, Spain) "Mechanical resonators based on nanotubes and graphene"

10:00-10:15

Imad Ibrahim (IFW-Dresden, Germany) "Growth of semiconducting enriched SWCNT on ST-cut quartz substrate by chemical vapor deposition"

10:15-10:45

Kazuya Terabe (National Institute for Materials Science, Japan) "Functionality controls of metallic and graphene oxides based on solid-state-nanoionics"

10:45-11:05

Dario Bercioux (Donostia International Physics Center, Spain) "Pseudo-spin-dependent scattering in carbon nanotubes"

11:05-11:25 11:25-11:40

Kazutoshi Haraguchi (Nihon Unviersity, Japan) "Synthesis and functions of platinum-polymer-clay nanocomposite gels fabricated via exfoliated clay-mediated in situ reduction"

11:40-12:15

Markus Maier (Omicron NanoTechnology GmbH, Germany) Peter Nirmalraj (IBM Research - Zurich, Switzerland) "Imaging molecular and atomic-scale materials in high density liquids"

13:00-13:15

Cesar Moreno (ICN2, Spain & ICYS-NIMS, Japan) "Three-dimensional imaging with submolecular resolution by atomic force microscopy"

13:15-13:30

Programme O K I I O

Coffee Break - Poster Session - Instrument Exhibition "Recent Advancements in Surface Science Instrumentation - The LT Nanoprobe"

12:45-13:00

Vladimir Popov (NUST "MISIS", Russia) "Investigation of non-agglomerated nanodiamonds inside aluminum matrix composites produced by mechanical alloying"

12:15-12:45

TNT2014

Wednesday â&#x20AC;&#x201C; October 29, 2014

Benjamin Grevin (CEA-CNRS-UJF, France) "High resolution non-contact AFM and Kelvin Probe Force Microscopy investigations of selforganized photovoltaic organic architectures"

13:30-15:00

K O O O

Lunch Nanodevices for Societal Challenges (Sponsored by ICN2 - Severo Ochoa Excellence Center)

15:00-15:10

Pablo Ordejon (ICN2, Spain) Welcome

Stephan Roche (ICN2 & ICREA, Spain)

Theory

15:25-15:55

Gianaurelio Cuniberti (University of Technology Dresden, Germany) "Multiscale modelling in Advanced Materials and Devices"

15:55-16:10

Pedro Gomez-Romero (ICN2 & CSIC, Spain) Energy Nanomaterials

16:10-16:40

Speaker to be defined

16:40-17:30 17:30-17:45

Coffee Break - Poster Session - Instrument Exhibition Arben MerkoĂ§i (ICN2 & ICREA, Spain)

Jesus M. De La Fuente (ICMA, Spain) "Designing inorganic nanoparticles for biotechnological applications"

18:15-18:30

Sergio Valenzuela (ICN2 & ICREA, Spain)

21:00

K I

ICT

18:30-19:00

I K

Biosensors

17:45-18:15

Speaker to be defined

Conference Dinner and Poster Award Ceremony

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15:10-15:25

Programme

TNT2014

Thursday â&#x20AC;&#x201C; October 30, 2014 10:45-11:15

Felix Ritort (Universitat de Barcelona & CIBER-BBN, Spain) "Force spectroscopy of anticancer drugs binding nucleic acids"

11:15-11:30

Hadi M. Zareie (Izmir Institute of Technology, Turkey & UTS, Australia) "Plasmonic Biosensors"

11:30-12:00

Daniel Ruiz Molina (ICN2 & CSIC, Spain) "Catechol-based bioinspired materials: from theranostics to water treatment"

12:00-12:30

Laura Fumagalli (IBEC, Spain) "Probing electric polarization of nano-objects and biomolecules using scanning probe microscopy"

12:30-13:00

Masashi Aono (Tokyo Institute of Technology, Japan) "Amoeba-inspired Nanoarchitectonic Computing for Solving Computationally Demanding Problems"

13:00-14:30

K O K K K

Lunch PARALLEL SESSION (PHD STUDENTS)

14:30-19:15

K: Keynote / I: Invited / O: Orals

PARALLEL SESSION (SENIORS)

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Programme

PARALLEL SESSION (PHD STUDENTS 1) 14:30-14:45

Mathieu Massicotte (The Institute of Photonic Sciences, Spain) Graphene/ Carbon nanotubes

"Photocurrent spectroscopy in TMDC-based van der Waals heterostructures"

14:45-15:00

Lucía Rodrigo (Universidad Autónoma de Madrid, Spain) Graphene / Carbon nanotubes

"Sublattice localized electronic states in atomically resolved graphene-Pt(111) edge-boundaries"

15:00-15:15

Rubén Sánchez-Hidalgo (University of Salamanca, Spain) Graphene / Carbon nanotubes

TNT2014

Thursday – October 30, 2014

"Graphene Oxide: the role of chemical composition on the properties of thin films"

15:15-15:30

Peter Weber (The Institute of Photonic Sciences, Spain) Graphene / Carbon nanotubes

"Coupling Graphene Mechanical Resonators to Superconducting Microwave cavities"

15:30-15:45

Achim Woessner (The Institute of Photonic Sciences, Spain) Graphene / Carbon nanotubes

"Highly confined low-loss plasmons in graphene-boron nitride heterostructures"

15:45-16:00

Carlos Couso (Universitat Autònoma de Barcelona, Spain) High spatial resolution spectroscopies under SPM probe

"Simulation of CAFM topography and current of structures based in high-k dielectrics and graphene"

16:00-16:15

Carlos Moya (Universitat de Barcelona, Spain) High spatial resolution spectroscopies under SPM probe

"Spin configurations of individual Fe3-xO4 nanoparticles"

16:15-16:30

Qian Wu (Universitat Autònoma de Barcelona, Spain) High spatial resolution spectroscopies under SPM probe

"CAFM study of Negative Bias Temperature Instability and Channel hot-carriers degradation in strained and non-strained MOSFETs"

16:30-17:00

Coffee Break - Poster Session - Instrument Exhibition PARALLEL SESSION (SENIORS 1)

17:00-17:15

Annalisa Calò (ICN2, Spain)

High spatial resolution spectroscopies under SPM probe

"Water footprints in tip-sample force reconstruction for dynamic atomic force microscopy in ambient conditions"

17:15-17:30

Neus Domingo Marimon (ICN2 & CSIC, Spain) High spatial resolution spectroscopies under SPM probe

"Scanning probe piezoresistance: a new experimental tool (or what happens when you put an elephant on stilettos)"

17:30-17:45

Gerald Kada (Keysight Technologies, Austria)

High spatial resolution spectroscopies under SPM probe

"Simultaneous Topography and Electrochemical Imaging (SECM)"

Josef Havel (Masaryk University, Czech Republic) Low dimensional materials (nanowires, clusters, quantum dots, etc.)

"Chalcogenide glasses – advanced nano-materials with still not completely resolved structure. Laser desorption ionization and mass spectrometry of clusters generated in gas phase for structure elucidation"

18:00-18:15

Alekber Kasumov (LPS, Universite Paris-Sud, France) Low dimensional materials (nanowires, clusters, quantum dots, etc.)

"Bismuth nanowires based Josephson junctions in very high magnetic fields"

18:15-18:30

Giancarlo Franzese (Universitat de Barcelona, Spain) Nanobiotechnologies & Nanomedicine

"The nanoparticles protein corona: How to extract a predictive molecular model from the experiments"

18:30-18:45

Esteve Juanola-Feliu (University of Barcelona, Spain) Nanobiotechnologies & Nanomedicine

"Design of a multipurpose nano-enabled implantable device for personalized medicine"

18:45-19:00

Aitor Lopeandia (Universitat Autònoma de Barcelona, Spain) Nanomaterials for Energy

"CMOS compatible µ-TEG based on single crystalline Si thin films"

19:00-19:15

Marketa Zukalova (UFCH JH, AS CR, Czech Republic) Nanomaterials for Energy

"Dense TiO2 Thin Layers Prepared by Sol-Gel for Dye Sensitized Solar Cells: Electrochemical Properties"

TNT2014 barcelona (spain)

october 27-31, 2014

| 19

K: Keynote / I: Invited / O: Orals

17:45-18:00

Programme

TNT2014

Thursday – October 30, 2014 PARALLEL SESSION (PHD STUDENTS 2) 14:30-14:45

Andreas Gang (TU Dresden, Germany)

Nanobiotechnologies & Nanomedicine

"Silicon nanowire based (bio) sensing"

14:45-15:00

Alejandro Hernández Albors (IQAC- CSIC, Spain) Nanobiotechnologies & Nanomedicine

"Development of a Columbimetric Immunosensor for the Detection of Human Cardiac Troponin I"

15:00-15:15

Cristina Paez-Aviles (SIC-BIO, University of Barcelona, Spain) Nanobiotechnologies & Nanomedicine

"Nanobiotechnology and Nanomedicine: Innovation and market Challenges towards H2020. A multi-KET approach"

15:15-15:30

Bernat Olivera (Universidad de Alicante, Spain) Nanomagnetism and Spintronics

"Kondo Physics in 4f metals: Gadolinium nanocontacts"

15:30-15:45

Kelli Hanschmidt (Univesity of Tartu, Estonia) Nanostructured and nanoparticle based materials

"Metal oxide fibers or micropipe preparation exploitation improving mechanism of metal alkoxide liquid threads"

15:45-16:00

Manel Molina-Ruiz (Universitat Autònoma de Barcelona, Spain) Other

"Microsecond-pulse heating nanocalorimetry: quasi-static method"

16:00-16:15

Chanyoung Yim (Trinity College Dublin, Ireland) Other

"Investigation of Photodiodes from Vapor Phase Grown MoS2"

16:15-16:30

Oriol Vilanova (Universitat de Barcelona, Spain) Theory and modelling at the nanoscale

"Predicting the kinetics of Protein-Nanoparticle corona formation in a simplified plasma"

16:30-17:00

Coffee Break - Poster Session - Instrument Exhibition PARALLEL SESSION (SENIORS 2)

17:00-17:15

Alicia Forment-Aliaga (ICMOL-Universidad de València, Spain) Nanomagnetism and Spintronics

"Magnetic Imaging and Manipulation of Molecular-based Nanoparticles"

17:15-17:30

Arantxa Fraile Rodríguez (Universitat de Barcelona, Spain) Nanomagnetism and Spintronics

"Direct imaging of tunable exchange bias domains in model Ni/FeF2 nanostructures"

17:30-17:45

Florian Otto (attocube systems AG, Germany) Nanomagnetism and Spintronics

"Sensitive scanning probe microscopy performed in an ultra-low vibration closed-cycle cryostat down to 1.5 K"

17:45-18:00

Helena Prima Garcia (ICMOL, Universidad de Valencia, Spain) Nanomagnetism and Spintronics

"Hybrid Materials for Molecular Spintronics: Fabrication of spin-OLEDs"

18:00-18:15

Jose Sanchez Costa (LCC, CNRS, France) Nanomagnetism and Spintronics

K: Keynote / I: Invited / O: Orals

"Surface plasmons spectroscopy for monitoring the spin crossover phenomena at the nanometric scale"

18:15-18:30

Cesar Elosua (Public University of Navarre, Spain) Nanostructured and nanoparticle based materials

"Optimization of an Optical Fiber Oxygen Sensor based on Metalloporphyrins Following Layer-byLayer method"

18:30-18:45

Gastón García (ALBA-CELLS, Spain)

Nanostructured and nanoparticle based materials

"The ALBA synchrotron light source: a tool for nanoscience"

18:45-19:00

Luca Gavioli (Università Cattolica del Sacro Cuore di Brescia, Italy) Nanostructured and nanoparticle based materials

"Highly bactericidal Ag nanoparticle films obtained by cluster beam deposition"

19:00-19:15

Boris Kulnitskiy (TISNCM, Russia)

NanoChemistry

"Unusual boron distribution in as-grown boron-doped diamond"

20 |

october 27-31, 2014

TNT2014 barcelona (spain)

09:00-09:30

Programme

Mark H. Rümmeli (Sungkyunkwan Univ. & CINAP-IBS, South Korea) "Room temperature in-situ nanostructure synthesis using electron beam irradiation"

09:30-09:45

Jordi Esquena (IQAC - CSIC, Spain) "Porous silica with complex dual morphology, prepared with a novel silica precursor in highly concentrated emulsions"

09:45-10:00

Lionel Patrone (IM2NP CNRS, France) "Impact of pi-conjugated self-assembled monolayer structure on their electrical properties"

10:00-10:15

Saverio Russo (University of Exeter, UK) "Elucidating the limiting factor of the electrical properties of WS2 and MoS2"

10:15-10:30

Gema Martinez-Criado (ESRF, France) "Exploring Single Semiconductor Nanowires with a Multimodal Hard X-ray Nanoprobe"

10:30-10:45

Riccardo Rurali (ICMAB-CSIC, Spain) "Heat transport across a SiGe nanowire axial junction: interface thermal resistance and thermal rectification"

10:45-11:15 11:15-11:45

Enrique Navarro (Pyrenean Institute of Ecology - CSIC, Spain) Maria Luisa Della Rocca (Université Paris Diderot, France) "Quantum interference effect in anthraquinone solid-state junctions"

12:00-12:15

Ladislav Kavan (J. Heyrovský Institute of Physical Chemistry, Czech Republic) "Nanocrystalline Boron-doped Diamond: Spectro/Photo/Electrochemical Properties and Prospective Applications in Solar Cells"

12:15-12:30

Ruben Esteban (Donostia International Physics Center, Spain) "Optoelectronics in plasmonic nanogaps"

12:50-13:20

Eva M. Weig (University of Konstanz, Germany) "Coherent control of nanoelectromechanical systems"

O O O

K O O O I K

Closing remarks & TNT2015 announcement

K: Keynote / I: Invited / O: Orals

13:20

Maia Garcia Vergniory (Donostia International Physics Center, Spain) "Magnetic interaction and magnetic fluctuations in topological insulators with ordered and disordered magnetic adatoms"

12:30-12:50

Coffee Break

"Assessing the environmental toxicity of nanomaterials: the case of silver nanoparticles"

11:45-12:00

TNT2014

Friday – October 31, 2014

TNT2014 barcelona (spain)

october 27-31, 2014

| 21

Only Posters of participants who fully processed their registration (payment done) appear below (as of 23/10/2014)

authors A. Al-Hartomy, Omar Alenezi, Mohammad Alguacil, Francisco J. Lopez F.A., Garcia-Diaz I.

topic

Saudi Arabia

Nanostructured and nanoparticle based materials

“Synthesis and characterization of WO3 for solar cell application”

senior

Kuwait

Nanostructured and nanoparticle based materials

“Optical Properties of Metal Oxide Nanostructures With Different Exposed Facets”

senior

Spain

NanoChemistry

“Extraction of metals from aqueous solutions using Tibased nanostructures: a review”

senior

Spain

Other

“New Generation of Nanomaterials for Green House Gases Adsorption”

senior

Denmark

Theory and modelling at the nanoscale

“Recent development of the DFT+NEGF code TranSIESTA, performance improvements and N-terminal”

Romania

Nanostructured and nanoparticle based materials

“Effect of electrochemical decoration of silver nanoparticles on arsenic detection performance”

senior

Spain

Theory and modelling at the nanoscale

“Interaction of gas molecules with a monoatomic MoS2 layer”

senior

Spain

Nanostructured and nanoparticle based materials

“Nanoparticulated ceria dispersed over silica: XPS study of the redox deactivation process”

senior

Spain

Theory and modelling at the nanoscale

“Generation of Diode-Like Structures with Maxwellian Series Resistance in Electrically Stressed HoTiOx Thin Films”

Alonso, Amanda Rebeca Contreras, Ahmad Abo Markeb, Xavier Font, Antoni Sánchez

Andersen, Nick Papior Mads Brandbyge

Baciu, Anamaria Aniela Pop and Florica Manea

Biel, Blanca Luca Donetti, Andrés Godoy, Francisco Gámiz, Pablo Pou

poster title

senior student

country

student

Blanco, Ginesa Ismael Cabeza, Lorena González, José Mª Pintado, Mariana Rocha, Clara Pereira, Cristina Freire

Blasco, Juli H. Castán, H. García, S. Dueñas, J. Suñé,M. Kemell, K. Kukli, M. Ritala, M. Leskelä, E. Miranda

student

Bos-Liedke, Agnieszka Zygmunt Miłosz, Natalia Michalak, Robert Ranecki,Mikołaj Lewandowski, Sławomir Mielcarek, Tadeusz Luciński, Stefan Jurga

Poland

Nanomagnetism and Spintronics

“Tuning the properties of epitaxial magnetite films by using different single crystal supports: Fe3O4(111)/Pt(111) vs. Fe3O4(111)/Ru(0001)”

senior

Germany

Graphene / Carbon nanotubes

“Towards waferlevel fabricated CNT sensors –Process improvements by length separation of single-walled carbon nanotubes”

student

Spain

Nanomaterials for Energy

“Hybrid Graphene Nanocomposites for Use as Electrode in Energy Storage Devices”

student

Spain

Theory and modelling at the nanoscale

“Interlayer coherence and entanglement in bilayer quantum Hall states at filling factor ν = 2/λ”

senior

Portugal

Nanostructured and nanoparticle based materials

“Gold Nanoparticles Supported on Carbon Materials for Cyclohexane Oxidation”

senior

Spain

Graphene / Carbon nanotubes

“The hidden influence of the flux of gas on the growth of graphene layers by low pressure chemical vapor deposition”

student

Poland

Graphene / Carbon nanotubes

“Core-shell structured CNT@CNT for the application of Supercapacitor”

senior

Korea

Nanofabrication tools & nanoscale integration

“Fabrication and Characterization of Nano wire grid polarizers film by magnetic soft mold”

senior

Romania

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Hybrid PbS QDs/silicon multispectral photodetector integrable with silicon ICs”

senior

Spain

NanoChemistry

“Functional ZrO2 nanoparticles as lubricant additives”

student

Böttger, Simon Sascha Hermann, Stefan E. Schulz

Caban-Huertas, Zahilia Jullieth Suárez-Guevara, Pedro Gómez-Romero

Calixto, Manuel Emilio Pérez-Romero

Carabineiro, S. A. C. L.M.D.R.S. Martins, M. Avalos-Borja, J.G. Buijnsters, A.J.L. Pombeiro, J.L. Figueiredo

Chaitoglou, Stefanos A. Musheghyan, V-M Freire, M.Reza Sanaee, E. Pascual, J-L Andújar and E. Bertran

Chen, Xuecheng RyszardJ.Kalenczuk, Ewa Mijowska

Choi, Doo-Sun Sunghwan Chang, Sang-Uk Jo, Myung Yung Jeong

Cristea, Dana Paula Obreja, Adrian Dinescu

Espina Casado, Jorge Humberto Rodiguez-Solla, Antolin Hernández Battez, Rosana Badía Laíño, Marta Elena Díaz García

Feng, Yuyi Kwang-Dae Kim, Sergej Andreev, Julian Reindl, Thomas Pfadler, James Dorman, Julian Kalb, Torsten Pietsch, Jonas Weickert, Lukas Schmidt-Mende

Germany

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Fabrication and Characterization of Free-Standing Silver Nanorod Arrays for Photovoltaic Devices”

Spain

Nanomagnetism and Spintronics

“Evolution of electronic and magnetic properties of iron oxide and cobalt ferrite nanocrystals probed by synchrotron-based X-Ray imaging and spectroscopy”

Germany

Nanostructured and nanoparticle based materials

“Ge1-xSnx alloys synthesized by ion-implantation: from epitaxial thin films to crystalline nanostructures”

Spain

Nanostructured and nanoparticle based materials

“Transport mechanism and high-field electroluminescence of silicon nanocrystals/SiO2 superlattices”

senior

Russia

Nanomaterials for Energy

“Usage of oxygen-modified CNT for electrode material of an air-hydrogen fuel cell”

senior

Denmark

Graphene / Carbon nanotubes

“Inelastic scattering and current-induced heating in graphene nanoconstrictions”

senior

Portugal

Nanobiotechnologies & Nanomedicine

“Biocompatible peptide-based hydrogels as nanocarriers for a new antitumoral drug”

Korea

Graphene / Carbon nanotubes

“Synthesis of Transparent Conducting Hybrid Film of Metalliuc SWCNT and Graphene”

senior

Japan

Nanostructured and nanoparticle based materials

“Damage and Wear Resistance of Al2O3-CNT Nanocomposites Fabricated by Spark Plasma Sintering”

senior

Spain

Graphene / Carbon nanotubes

“Entanglement in a spin-valley graphene system”

senior

Spain

Theory and modelling at the nanoscale

“Drift-Diffusion Simulation of MoS2 channel FETs”

student

Fraile Rodríguez, Arantxa Carlos Moya, Nicolás Pérez, Cinthia Piamonteze, Xavier Batlle and Amílcar Labarta

Gao, Kun S. Prucnal, C. Baehtz, R. Huebner, W. Skorupa, M. Helmand and Shengqiang Zhou

Garrido, Blas J. López-Vidrier, Y. Berencén, S. Hernández, O. Blázquez, S. Gutsch, D. Hiller,P. Löper, M. Schnabel, S. Janz, M. Zacharias

Glebova, Nadezda V. A.A. Nechitailov, A.O. Krasnova

Gunst, Tue Jing-Tao Lü, Per Hedegaard, Mads Brandbyg

student

senior

student

Hortelão, Ana C. L. Bruno F. C. Hermenegildo, Helena Vilaça, Goreti Pereira, Bing Xu, Maria-João R. P. Queiroz , José A. Martins, Paula M. T. Ferreira, Elisabete M. S. Castanheira

Huh, Wansoo Kwang-Hoon Lee

Jang, Byung-Koog K.S. Lee

Jódar, Esther Antonio Pérez-Garrido and Fernando Rojas

Jovell, Ferran Xavier Cartoixà

student

Karahaliloglu, Zeynep Eda Yalçın, Murat Demirbilek, Emir Baki Denkbaş

Turkey

Nanobiotechnologies & Nanomedicine

“Antibacterial silk fibroin e-gel scaffolds for tissue engineering applications”

student

Germany

NanoOptics / NanoPhotonics / Plasmonics

“Fully analytic spaser model: Understanding threshold limitations”

student

Korea

Nanostructured and nanoparticle based materials

“Self-Assembled Dendron-Cyclodextrin Nanotubes for Biosensory Platform”

senior

Russia

Graphene / Carbon nanotubes

“Mechanism of Low-voltage Field Emission from Carbon Nanotube Cathode”

student

Spain

Nanobiotechnologies & Nanomedicine

“Safety and internalization effectiveness of magnetic iron oxide nanoparticles”

student

United Kingdom

Graphene / Carbon nanotubes

“Electronic structure of stripped graphene nanoribbons delimited by sp3 defect lines: A density functional theory study”

student

China

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“High bright Ag-carbon dots-silica hybrid mesoporous nanosphere”

senior

Spain

Theory and modelling at the nanoscale

“Optical spectra and quasiparticle energies of molecules using a local basis”

senior

United Kingdom

Nanomaterials for Energy

“Temperature-controlled growth of single-crystal Pt nanowire arrays for high performance catalyst electrodes in polymer electrolyte fuel cells”

student

Spain

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Time-Dependent Density Functional Theory Calculationson Graphene Nanoflakes: Optical Properties and Electron Energy Loss Spectroscopy”

student

Kewes, Günter Rogelio Rodriguez-Oliveros, Kathrin Höfer, Alexander Kuhlicke, Kurt Busch and Oliver Benson

Kim, Chulhe Jeonghun Lee

Kosakovskii, German Z.Ya Kosakovskaya, E.V. Blagov, Yu.I. Latyshev, A.P. Orlov, A.M. Smolovich

Lazaro-Carrillo, Ana Macarena Calero, Lucía Gutiérrez, Gorka Salas, Yurena Luengo, Pilar Acedo, M. del Puerto Morales, Rodolfo Miranda, Angeles Villanueva

Lian, Jian Xiang Y. Olivier, D. Beljonne

Liu, Chunyan Zhiying Zhang, Yun Liu

Ljungberg, Mathias P. Peter Koval, Francesco Ferrari, Dietrich Foerster, Daniel Sanchez-Portal

Lu, Yaxiang Shangfeng Du, Robert Steinberger Wilckens

Marchesin, Federico P. Koval, D. Foerster, D. Sánchez-Portal

Markiewicz, Roksana Stefan Jurga

Poland

Nanostructured and nanoparticle based materials

“Ionic liquids and deep eutectic solvents in the preparation of nanostructures”

Spain

Graphene / Carbon nanotubes

“The effect of photon energy on hot-carrier mediated photoresponse in graphene”

student

Spain

NanoOptics / NanoPhotonics / Plasmonics

“Infrared Resonant Antenna Tips for Enhanced NearField Mapping of Molecular Absorption”

student

Mexico

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Structural and electronic properties of bimetallic AunAgm, (n+m=20, n:m=1:0, 3:1, 1:1, 0:1) clusters and their ions: a relativistic DFT study”

senior

France

Graphene / Carbon nanotubes

“Investigation of metal oxides deposition on electrical properties of CVD Graphene”

student

Iran

NanoChemistry

“Nanohybrid of Activated Carbon Nanotube-Porphyrin as a Recyclable Catalyst for Aqueous Oxidation of Hydrocarbons with n-Bu4NHSO5”

senior

Romania

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Zinc oxide quantum dots as a candidate for memory devices”

senior

Spain

Nanobiotechnologies & Nanomedicine

“Innovation Ecosystems and Market Challenges in Nanobiotechnology and Nanomedicine: A multi-KET analysis within Horizon 2020”

student

Korea

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Nonequilibrium Carrier Dynamics of Si1-x Gex nanowires measured by Optical Pump-THz Probe Spectroscopy”

Massicotte, Mathieu K.J. Tielrooij and F.H.L. Koppens

senior

Mastel, Stefan Florian Huth, Andrey Chuvilin, Martin Schnell, Iban Amenabar, Roman Krutokhvostov and Rainer Hillenbrand

Molina, Bertha Alonso E. Viladomat, Jorge R. Soto and Jorge J. Castro

Mzali, Sana O. Bezencenet, J-P Mazellier, B. Dlublak, M-B Martin, B.Servet, S. Xavier, A. Centeno, S. Bansropun, P.Seneor, P. Legagneux

Naeimi, Atena Jilla saffari

Obreja, Paula Dana Cristea, Cristian Kusko, Raluca Gavrila, Iuliana Mihalache, Mihai Daniala, Adrian Dinescu

Paez Aviles, Cristina Magdalena Esteve Juanola-Feliu and Josep Samitier

Park, Jaehun Woo-Jung Lee, Hyejin Choi, Seonghoon Jung, Mann-Ho Cho

senior

Patrone, Lionel Virginie Gadenne, Grégory Delafosse, Laure Fillaud, Bruno Jousselme, Volodymyr Malytskyi, Jean-Manuel Raimundo

France

Nanostructured and nanoparticle based materials

“Towards Self-Assembled Molecular Nanodielectrics on Ge and GaAs”

senior

Spain

Graphene / Carbon nanotubes

Remote Plasma Enhanced Chemical Vapor Deposition (rPE-CVD) of Graphene on Various Substrates

senior

Spain

NanoChemistry

“Adsorption of Silver Nanoparticles on the surface of Metal Organic Frameworks”

senior

Romania

Nanostructured and nanoparticle based materials

“Assessment of carbon nanotubes-epoxy composite electrode for in-field detection applications”

senior

Russia

Nanostructured and nanoparticle based materials

“Carbon nanomaterials as result of nanodiamonds annealing”

senior

Spain

Nanomaterials for Energy

“Giant Magnetoresistance with Temperaturedependent Crossover in FeNi3-graphene Nanocomposites”

senior

Spain

Other

“A comprehensive resistive memory characterization through the analysis of conductive filaments”

senior

Spain

Graphene / Carbon nanotubes

“Zitterbewegung in monolayer Silicene”

senior

Venezuela

Nanostructured and nanoparticle based materials

“Titanium Dioxide Nanofibers photosensitized with Porphyrin for Efficient Degradation of textile dyes in Water”

student

Spain

Nanostructured and nanoparticle based materials

“Synthesis of fullerene on the surface of carbon nanoparticle by arc discharge method”

student

Pellegrin, Eric M. González Cuxart, I. Šics, M. J. U. Foerster, L. Aballe Aramburu, V. Carlino, A. R. Goñi, E. Pach and G. Sauthier

Peña Méndez, Eladia María E.M., Rybaková, S., Conde-González, J.E., Havel, J.

Pop, Aniela Adriana Remes, Florica Manea

Popov, Vladimir A. Prima-Garcia, Helena G. Abellána, E. Coronadoa

Roldan, Juan Bautista M.A. Villena, F. Jiménez-Molinos, E. Romera, P. Cartujo-Cassinello

Romera, Elvira J. B. Roldan and F. de los Santos

Rosales, Maibelin Yadarola Ciro, Zoltan Tamara

Sanaee, M. Reza Enric Bertran

Sandoval, Stefania Nitesh Kumar, A. Sundaresan, C. N. R. Rao, Amparo Fuertes and Gerard Tobias

Spain

Graphene / Carbon nanotubes

“Enhanced Thermal Oxidation Stability of Reduced Graphene Oxide by Nitrogen Doping”

Spain

NanoOptics / NanoPhotonics / Plasmonics

“Polarization-Resolved Near-Field Mapping of Nanoscale (λ0/310) IR Transmission Line Modes”

Spain

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Facile Electrochemical Template Synthesis of CoPt Alloyed Mesoporous Nanorods from Microemulsions Using an Ionic Liquid”

student

Poland

Nanostructured and nanoparticle based materials

“SurfaceFunctionalization of Magnetic Nanoparticles For Biomedicine”

senior

United Kingdom

Theory and modelling at the nanoscale

“Computer simulations of nanosized biomaterials”

senior

France / Taiwan

Theory and modelling at the nanoscale

“On Channel Shape Variation of 10-nm-Gate Gate-AllAround Silicon Nanowire MOSFETs”

student

Spain

Low dimensional materials (nanowires, clusters, quantum dots, etc.)

“Electrochemical synthesis of CoPt nanoparticles over carbonaceous substrates for electrocatalysis”

senior

Germany

Graphene / Carbon nanotubes

“Graphene microelectrode arrays for cell stimulation”

student

Spain

Risks-toxicity-regulations

“Size dependence effects of Aluminium oxide nanoparticles on red blood cells”

Spain

Graphene / Carbon nanotubes

“Near-Field Mid-Infrared Photocurrent in Graphene”

Schnell, Martin P. Sarriugarte, A. Chuvilin, R. Hillenbrand

Serrà, Albert Elvira Gómez, Elisa Vallés

Szelag, Anna Emerson Coy, Blazej Scheibe, Stefan Jurga

Tilocca, Antonio

Tomar, Saurabh Pei-Jung Chao, Han-Tung Chang and Yiming Li

Vallés, Elisa Elvira Gómez, Sergi Grau, Juan M. Feliu, Manuel Montiel

Viana Casals, Damià Martin Lottner, Michael Sejer Wismer, Felix Rolf, Lucas Hess and Jose Antonio Garrido

Vinardell, Maria Pilar Sordé A, Mitjans M

student

senior

Woessner, Achim Mark B. Lundeberg, Pablo Alonso-González, Qiong Ma, Ivan Nikitskiy, Pablo Jarillo-Herrero, Rainer Hillenbrand and Frank H.L. Koppens

student

Xuriguera, Elena Spain

Nanostructured and nanoparticle based materials

“Pulsed laser depositon of biaxially textured SrTiO3 buffer layer on cube textured Cu-based substrate”

senior

Spain

Graphene / Carbon nanotubes

“Flexible reduced graphene oxide gas sensor deposited by electrospray”

senior

Czech Republic

Nanostructured and nanoparticle based materials

“Graphite/ZnO nanorods junction for ultraviolet photodetectors”

senior

Turkey

Nanostructured and nanoparticle based materials

“Synthesis of High Surface Area Titania Based Nanoparticles and the Effect of Surfactants”

senior

Cristea, Dana

Romania

“Research results on graphene processing technologies for nanoelectronics and photonics”

Gómez Morales, Jaime

Spain

“Bioinspired 2D apatite/graphene hybrid nanocomposites for biomedical applications”

Patterson, Michael D.

U.S.A.

“Graphene Biosensors — The Next Frontier In Medical Diagnostics?”

Porti, Marc

Spain

“Activities of the Reliability o Electron devices and circuits group (UAB)”

Vinardell, Maria Pilar

Spain

“Cytotoxicity of Nanomaterials in vitro”

J. A. Padilla, L. Rodríguez, A. Vannozzi, G. Celentano

Xuriguera, Elena O. Monereo, A. Varea, A. Cirera

Yatskiv, Roman Maria Verde, Jan Grym

Yurum, Alp Miad Yarali, Selmiye Alkan Gürsel

FLAG-ERA Session

Synthesis and characterization of WO3 for solar cell application Omar A. Al-Hartomy

Department of Physics, Faculty of Science, King Abdul Aziz University, Jeddah, P.O. Box, 80203, Jeddah 21589, Saudi Arabia.

Abstract The present study reports a convenient ion irradiated template method for the synthesis of WO3 nanowire arrays. The structural, morphological and optical properties of the nanowires heterojunctions are studied using absorption and transmittance spectra . The results indicate that WO3 nanowires having mean diameter 10 nm which are uniform. Earlier many experimental as well as theoretical studies are discussed for application semiconductor nanocopmosite for solar cells. To the best of our knowledge no efforts has been made to synthesize WO3 semiconductor inline with work reported earlier. The optical band gap energy of WO3 sample was found to be 2.6 eV. The dispersion in this value may originate in quantum confinement inside the nano crystalline material. The particle size is further confirmed by XRD while surface morphology is determined by SEM. The photovoltaic performances of the resulting WO3 nanowire arrays have also been accessed using electrochemical analyser. The power efficiency of this solar cell is found to be 7.59% [1-9]. Keywords: Nanowire arrays, quantum confinement, absorbance, transmittance, cyclic voltagrams and nuclear magnetic resonance.

References: [1] Fahoume, M., Maghfoul, O., Aggour, M., Hartiti, B., Chraibi F. and Nnaoui, A., Sol. En. Mat. Sol. Cell. 2006, v. 90, p. 1437 [2] Monreal, H.A., Chacon-Nava, J.G., Arce-Colunga, U., Matinez, P.G., Casillas C.A. and Martinez- Villafane, A., Mic. Nano Lett. 2009, v. 4, p. 187 [3] Allon I.H. and Peidong Y., Chem. Rev. 2010, v. 110, p. 527 [4] Chakravarti S.K. and Vetter, J., Rad. Meas. 1998, V. 29(2), p. 149 [5] Cornelius, T. W. , Apel, Y.U., Balanzat, E., Bouffard, S., Trautmann, C., Karim, S. and Neumann, R., Nucl. Instr. Meth. B, 2007, v. 265, p. 553 [6] Dai, H. Hafner, J.H., A.G. Rinzler, Colbert D. T. and Smally, R. E., Nature 1996, v. 384, p.147 [7] Han, W.Q., Fan, S.S., Li, Q.Q. and Hu, Y.D., Sci. 1997, v. 277, p. 1287 [8] Kondo Y. and Takayanagi, K., Sci. 2000, v. 289, p. 606 [9] Sima M., Enculescu, I., Visan, T., Spohr R. and Trautmann, C., Mol. Cryst. Liq. Cryst., 2004, v. 418(21), p. 749

Optical Properties of Metal Oxide Nanostructures With Different Exposed Facets Mohammad R. Alenezi College of Technological Studies, Public Authority for Applied Education and Training, P.O. Box 42325 Shuwaikh, Kuwait mr.alenezi@paaet.edu.kw Abstract Controlling the morphology of crystals in order to control its functional properties is essential to fabricate high performance devices for a variety of uses. nanostructures have gained a great deal of attention lately due to their great potential in many applications benefiting from their reduced 1-5 dimensionality and high surface to volume ratio. Nanostructures with different exposed facets are synthesized hydrothermally at low temperature (nanowires, nanodisks, and nanostars) as shown in figure 1(a)-(c), respectively. The morphology and structure of these nanostructures are characterized by means of SEM, STEM, XRD, and SAED. The optical properties of nanostructures showing different exposed facets are also characterized using XPS analysis. Based on XPS data (figure 1(d)-(f)), SEM (figure 1(a)-(c)), and SEAD (inset of figure 1(a)-(b)) analysis, nanostructures with polar exposed facets (nanodisks) have the largest number of chemosorbed oxygen on its surface. References

[1] Alenezi, M. R.; Henley, S. J.; Emerson, N. G.; Silva, S. R. P. Nanoscale, (6), Ă [2] Alenezi, M. R.; Alshammari, A. S.; Jayaw ardena, K. D. G. I.; Beliatis, M. J.; Henley, S. J.; Silva, S. R. P. J. Phys. Chem. C Ă [3] Alenezi, M. R.; Abdullah S. Alshammari, Peter D. Jarow ski, Talal H. Alzanki, Simon J. Henley, and S. R. P. Silva. Langmuir, 2014, 30, 3913Âą3921. [4] Beliatis, M. J.; K. K.; Gandhi, Lynn J. Rozanski, Rhys Rhodes, Liam McCafferty, Alenezi, M. R.; Alshammar i, A. S.; Mills, C. A.; Jayaw ardena, K. D. G. I.; Henley, S. J.; Silva, S. Ravi P. Adv. Mater. 2014, 26, 2078Âą2083. [5] Alenezi, M. R.; Alzanki, T. H.; Almeshal, A. M.; International Journal of Science and Research. 2014, 3, 588Âą591.

Figures

(b)

(a)

ZNWs

(e) (c)

(b) (d) ZNWs

ZNDs

(c)

(f)

OV OV

OC (15%) OC (3%)

Figure 1. SEM images of ZnO (a) nanowire (inset: SAED pattern), (b) nanodisk (inset: SAED pattern), and (c) nanostar; XPS spectra of ZnO (e) nanowires, (f) nanodisks, and (g) nanostars.

(15%)

EXTRACTION OF METALS FROM AQUEOUS SOLUTIONS USING Ti-BASED NANOSTRUCTURES: A REVIEW Alguacil F.J., Lopez F.A., Garcia-Diaz I. Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo, 8, 28040, Madrid, Spain fjalgua@cenim.csic.es Abstract Titanium-based nanostructures due to their special physicochemical properties are receiving a great deal of interest for the application in several fields. Among these applications, the Ti-based nanostructures are finding their value as “green adsorbents” or ion exchange for metals present in aqueous solutions arising from various environments. The present paper reviewed the applications of these amazing materials in the removal of metals from heavy. The precursor used to prepare various form of titanium-based nanostructure is TiO2. The first description of how titanate nanotubes were obtained by hydrothermal process in alkaline media dated back 1998. In the process, anatase powders were chemically treated with 5-10 M NaOH solutions 2 2 during 20 h at 110ºC, the as obtained nanotubes presented a specific surface as high as near 400 m /g [1]. This type of treatment was constantly repeated in all the literature consulted in this work. Different titanate-based nanostructures can be isolated by variation of the sodium hydroxide concentration and the reaction time, some of then are nanoparticles, nanosheets, nanotubes, nanowires and nanoribons. Titanate nanotubes were used for the removal of copper (II) from aqueous solutions [2]. The adsorption + capacity of the nanotubes depends of the amount of Na in the nanotube, since if this presence is not very low (i.e. higher than 7.2 % wt.), the nanotubes are good adsorbents of copper (II) with a maximum capacity of near 1.9 mmol/g at a pH value 5. Titanate fibers with NaxH2-xTi3O7·nH2O (i.e. x= 2) were investigated as adsorbents for copper (II) [3]. The results concluded that the nanofibers with the higher sodium content are the most effective adsorbents for copper (II) being this adsorption greater as the pH of the solution is increased, reaching a maximum of 99% at pH of 4, when the solution of 100 mg/L metal were tested. As (V) is mainly adsorbed at acidic pHs values, As (III) is best removed from aqueous solutions at pH around 7 using these nanoadsorbents [4]. The temperature in which nanotubes are formed influences the arsenic uptake as results in Table 1 shown, is far greater than that obtained by the use of titanium oxide powders. The maximum capacity of As (III) and (V) obtained by the Langmuir model is 0.8 mmol/g and 2.8 mmol/g respectively. It is described the adsorption of lead (II) using titanate nanotubes [5]. The high lead loadings onto de nanotubes, as much as near 1.0 mmol Pb(II)/g adsorbent, can be achieved at pH values of 5-6. The adsorption decrease with the decrease of the pH values. Three types of titanate adsorbents were investigated to remove Pb (II) from aqueous solutions, nanotubes, nanowires and amorphous nanoparticles [6]. In the three cases, the metal adsorption fitted to the Langmuir model. The adsorption order for the metal is found to be: nanotubes>nanoparticles>nanowires with capacities of near 0.7, 0.5 and 0.4 mmol/g for equilibrium lead concentration of near 1 g/L, respectively Various divalent cations were used to determine the adsorption properties of sodium titanate nanotubes [7]. The adsorption order, found at pH 3 and ionic strength of 0.1 is Pb>Cd>Cu>Zn>Ca>Sr>Ni. This adsorption capacity can be linker with the hard and soft acids and bases theory. The nanotubes showed higher affinity for softer acids, so the nanotubes investigated in this work can be considered soft bases. Ti nanoflowers has large specific surface area and their performance in the removal of heavy metals were thus investigated, the metals investigated were lead (II) and mixed aqueous solutions of cadmium (II), zinc (II) and nickel (II) [8]. Experimental results showed that removal order found for these nanocompounds is Cd (II)>Zn (II)>Ni (II) with maximum adsorption capacities of 0.7, 0.4 and 0.3

mmol/g, respectively, for a metal (each) equilibrium concentration around 0.17, 0.10 and 0.09 g/L. The performance of these adsorbents with respect to the metals removal is compared against those of titanate nanotubes or nanowires, for each metal, the adsorption capacity follows the next order: nanoflowers>nanotubes>nanowires. With respect to lead (II) adsorption using nanoflowers, adsorption equilibrium is reached within less than 10 min of contact of the aqueous solution and the adsorbent, this quick adsorption is related to the structural characteristics of titanate nanoflowers. The adsorption power of titanate nanotubes on multi-elemental solutions was investigated in systems containing Pb (II), Cu (II), Cr (III) and Cd (II) [9]. From adsorption experiments carried out at an aqueous pH value of 5, the adsorption order and maximum metal loading was: Pb (II) (2.6 mmol/g)>Cd (II) (2.1 mmol/g)>Cu (II) (1.9 mmol/g)>Cr (III) (1.4 mmol/g), whereas the corresponding metals equilibrium concentration are: 0.50, 0.10, 0.13 and 0.14 g/L, respectively. In the adsorption of Pb(II), Cd(II) and Cr (III) by titanate nanotubes [10], it was found that the pH of the aqueous solutions is the key factor for metal adsorption, whereas the presence of humic acid in this solution also influenced favorably the metal adsorption, due to the formation of metal-humic acid complexes, which evidently alter the adsorption capacity of the nanotubes. In the case of the pH, the metals adsorption is enhanced as the pH of the aqueous solution increases from 2 to 6, and follows the order lead (II)>cadmium (II)>chromium (III), however at the highest pH value, chromium is adsorbed preferably to cadmium. The presence of humic acid favored metal adsorption at concentration of the acid in the solution below 1 mg/L and above 5 mg/L, whereas between these two limiting values the metals adsorption decay. The various tested Ti-based nanostructures certainly presented good properties as adsorbents of metals from aqueous solutions of various sources; however their application in this environmental field is not fully investigated. Very little information is currently in our hands related with the performance of these nanostructures when used in a continuous operation. The future for these nanoadsorbents in this field seemed to be promising and worth to be investigated References [1] Kasuga, T., Hiramatsu M., Hoson A., Sekino T. and Niihara K., Langmuir, 14, (1998), 3160 [2] Liu S.S., Lee C.K., Chen H.C., Wang C.C. and Juang L.C., Chemical Engineering Journal, 147, (2009), 188. [3] Li N., Zhang L., Chen Y., Tian Y. and Wang H., Journal of Hazardous Materials, 189, (2011), 265. [4] Niu H.Y., Wang J.M., Shi Y.L., Cai Y.Q. and Wei F.S., Microporous and Mesoporous Materials, 122, (2009), 28. [5] Chen Y.C., Lo S.L and Kuo J., Colloids and Surfaces A: Physicochemical and Engineering Aspects, , 361, (2010), 126. [6] Huang J., Cao Y., Deng Z. and Tong H., Journal of Solid State Chemistry, 184, (2011), 712. [7] Du A.J., Sun D.D. and Leckie J.O., Journal of Hazardous Materials, 187, (2011), 96. [8] Huang J., Cao Y., Liu Z., Deng Z., Tang F. and Wang W., Chemical Engineering Journal, 180, (2012), 75. [9] Liu W., Wang T., Borthwick A.G.L., Wang Y., Yin X., Li X., and Ni J., Science of the Total Environment, 171, (2013), 456-457. [10] Wang T., Liu W., Xiong L., Xu N. and Ni J., Chemical Engineering Journal, 366, (2013), 215-216. Tables Table 1. As(III) and (V) adsorption using various titanate nanotubes. Temperature of formation As(III), mmol/g Ă&#x203A; & 0.08 Ă&#x203A; & 0.11

As(V), mmol/g 0.08 0.13

Time: 300 min. The adsorption using the pristine titanium oxide powder is 0.02 mmol/g and 0.03 mmol/g for arsenic (III) and (V), respectively.

New Generation of Nanomaterials for Green House Gases Adsorption Amanda Alonso, Rebeca Contreras, Ahmad Abo Markeb, Xavier Font, Antoni SĂĄnchez Chemical Engineering Department, Autonomous University of Barcelona, Spain

amanda.alonso@uab.cat Abstract The Green House Gases (GHG) capture and storage could play a significant role in reducing emissions in the atmosphere. Carbon dioxide (CO2) is the most important gas by volume and so it has been widely studied and captures the focus in most of the reports on global warming. [1]. However, there are other GHGs with lower volume emissions but which contribute 40% of the radiation from GHGs. Thus, Schulze et al. (2009) emphasize the importance in future emissions of methane (CH4) and nitrous oxide (NO2) in the GHG balance in Europe [2]. There are several technologies for CO2 capture including adsorption, absorption and through membranes, among others [3]. They include several adsorbents such as: active carbon [4] zeolites [5] and mesoporous silica [6]. The above technologies based on adsorption processes, are limited regarding retention capabilities of GHG per absorber mass. In this regard, there is widespread interest in the development of advanced absorbent materials with better characteristics than conventional materials and incorporating appropriate functionality for each specific pollutant. Nanotechnology can be the solution. Recently, there have been some studies that used nanomaterials for CO2 removal. For instance, the use of carbon nanotubes (CNTs) and nanotubes functionalized with amines by physical adsorption processes. The comparison of these materials with commercial adsorbents such as active carbon and zeolite suggests that these compounds are good candidates for CO2 absorption [7]. One of the other hand, some technologies used to capture CO2 at high concentrations is the combustion of solid carriers oxygen ("Chemical Looping Combustion,"CLC) which is an alternative to the conventional combustion with subsequent separation of CO2 (capture in post-combustion). In this technology, metal oxides are used as transporters oxygen as Fe2O3, NiO and Mn2O3 among others, on inert supports. However this technology has not yet carried out on a large scale, although the results are promising, mainly by low energy costs required in the process [8]. A very few results were found for the use of inorganic nanoparticles (NPs) for CO2 removal and even less for the removal of other GHGs such as NO2, CH4 and fluorinated compounds. While in the field of gas treatment research has not been widely studied, in the field of environmental engineering and water treatment processes it is seen more research. Thus, some work developed by our group and others for removal of heavy metals [9] or of nutrients [10] by using inorganic NPs show the potential of nanotechnology for contaminant removal applications. In this sense, it has been studied in this work the adsorption of CH4 on different type of NP and nanomaterials including: iron oxide (Fe3O4) NPs, titanium oxide (TiO2) NPs, ZrO2 NPs as well as Fe3O4 and MnFe2O4 NPs stabilized [11] in sulfonated polymers or zeolites among other porous supports of interest. The synthesis and characterization of various types of nanomaterials was studied in order to present an improvement in adsorption capacity compared to the materials currently in use. They have been used for removal CH4 in continuous experiment. The results obtained so far showed an increase in the adsorption kinetics for both Fe3O4 NPs and those stabilized in polymer in comparison with commercial Activated Carbon or Zeolites. References 1) S. Pacala, R. and Socolow R, Science 13, 968Í˛972 (2004).

2) E.D. Schulze, S. Luyssaert, P. Ciais, A. Freibauer and I. A. Janssens. Nature Geoscience 2, 842Ͳ850 (2009) 3) D. Aaron and C. Tsouris., Separation ScienceTechnology 40, 321–348 (2005). 4) R.V. Siriwardane, M.S. Shen, E.P. Fisher and J.A. Poston., Energy Fuels 15, 279–284 (2001). 5) J. Prezepiórski, M. Skrodzewicz and A.W. Morawski., Applied Surface Science 225, 235–242 (2004) 6) F. Zheng, D.N. Tran, B.J. Busche, G.E. Fryxell, R.S. Addleman, T.S. Zemanian and C.L. Aardahl, Industrial Engineering Chemistry Research 44 3099–3105 (2005). 7) S.K. Smart, A.I. Cassady, G.Q. Lu and D.J. Martin.Carbon 44, 1034–1047 (2006). 8) A.A. Olajire.Energy 35, 2610Ͳ2628 (2010). 9) S. Recillas, J. Colón, E. Casals, E. González, V. Puntes, A. Sánchez and X. Font., Journal of Hazardous Materials, 184, 425Ͳ431 (2010). 10) S. Choe, Y.Y. Chang, K.Y. Hwang and J. Khim. Chemosphere 41, 1307Ͳ1311 (2000). 11) A. Alonso, Development of polymeric nanocomposites with enhanced distribution of catalytically active or bactericide nanoparticles, Thesis 2012, Universitat Autònoma de Barcelona

Recent development of the DFT+NEGF code TranSIESTA, performance improvements and N -terminal Nick Papior Andersen, Mads Brandbyge The Technical University of Denmark, Ørsteds Plads, 2800 Kgs. Lyngby, Center for Nanostructured Graphene (CNG), DTU Nanotech Denmark nickpapior@gmail.com

DFT+NEGF methods are increasingly important tools for the interpretation and investigation of physical phenomena in experiments. In this work we present a re-implementation of the TranSIESTAcode [1] based on SIESTA [2]. The NEGF method relies on inverting the left hand side to obtain the Green’s function (here shown with orbital indices µ, ν)

1 X

= Gµν , (1) zS − H − Σi

µν

where H, S and Σi are respectively the Hamiltonian, overlap and self-energy matrices. The density matrix is directly related to the Green’s function in equilibrium through Dµν ∝ Gµν . The Hamiltonian will inherently contain many zero elements due to the linear combination of atomic orbital (LCAO) approach in SIESTA. By taking advantage of this we can improve the performance and reduce memory requirements of TranSIESTA. An entire re-write of the code have surmounted to drastic performance improvements and memory reductions. We have implemented three variants of solution methods for the code, 1) a block tri-diagonal inversion algorithm which scales linearly with constant block sizes [3, 4] (LAPACK/BLAS), 2) a sparse inversion algorithm based on the MUltifrontal Massively Parallel sparse direct Solver (MUMPS, [5, 6]) which selectively calculates inverse elements of a matrix, and 3) the direct method using LAPACK/BLAS routines [7]. The block tri-diagonal and MUMPS routines can thus drastically decrease memory requirement of the code by removing unneeded elements from the Hamiltonian and overlap on the left hand side of Equation (1). The density matrix is equivalently only defined in the LCAO space which allows to only calculate a subset of matrix elements of the Green’s function. This further reduces the memory requirement and the computational complexity. We here present data for our block tri-diagonal routine with an example of pristine graphene using a 2 hexagon wide electrode and device. The basic unit cell is made up of 24 atoms and we increased the length of the system by multiplying this unit cell going up to ≈ 350 atoms. Our calculations are performed on a 12 core XeonE5-2620@2GHz with 32GB of ram (≈ 2.67 GB per core) and with the exact same settings for v3.2 and our work. The timings are seen in Fig. 1 together with the speedup of both the equilibrium calculation and the non-equilibrium calculations. At around 300 atoms v3.2 exhausts the memory in non-equilibrium which does not allow us to extend the analysis of comparison. However this work allows extending the system to 2160 atoms and still a single non-equilibrium SCF iteration step takes only 2351 s. Note that this is nearly a fourth of the time spent in v3.2 for 300 atoms! Our implementation is generalised to handle N -terminal devices in TranSIESTA which will provide calculations of complex systems such as those schematised in Fig. 2. Furthermore the calculation of slabs (N = 1) within the method of NEGF will provide reduction in system sizes due to the removal of the mirror plane by imposing strict bulk, thus removing spurious non-bulk effects associated with the surface layers.

References [1]

M. Brandbyge et al. “Density-functional method for nonequilibrium electron transport”. In: Physical Review B 65.16 (Mar. 2002), pp. 1–17.

[2]

J. M. Soler et al. “The SIESTA method for ab initio order-N materials simulation”. In: Journal of Physics: Condensed Matter 14.11 (Mar. 2002), pp. 2745–2779.

[3]

E. M. Godfrin. “A method to compute the inverse of an n-block tridiagonal quasi-Hermitian matrix”. In: Journal of Physics: Condensed Matter 3.40 (Oct. 1991), pp. 7843–7848.

[4]

M. G. Reuter and J. C. Hill. “An efficient, block-by-block algorithm for inverting a block tridiagonal, nearly block Toeplitz matrix”. In: Computational Science & Discovery 5.1 (July 2012), p. 014009.

[5]

P. R. Amestoy et al. “A Fully Asynchronous Multifrontal Solver Using Distributed Dynamic Scheduling”. In: SIAM Journal on Matrix Analysis and Applications 23.1 (Jan. 2001), pp. 15–41.

[6]

P. R. Amestoy et al. “Hybrid scheduling for the parallel solution of linear systems”. In: Parallel Computing 32.2 (Feb. 2006), pp. 136–156.

[7]

E. Anderson et al. LAPACK Users’ Guide. Third. Society for Industrial and Applied Mathematics, 1999. Equilibrium V = 0

Non-equilibrium V = 0.5 V 30

30 8,000

TranSIESTA 3.2 This work 2,000

Memory exhaust

6,000

4,000

100

10 2,000

1,000

200

300

0 400

Speedup

Time per SCF iteration [s]

3,000

Speedup

100

200

300

0 400

Atoms in unit cell Figure 1: A direct comparison of a pristine graphene calculation showing speed-ups in excess of 20×. We could not go to higher number of atoms for v3.2 due to limited memory on the machine (2.67GB per core), yet this work could handle 2160 atoms with a timing of 518 s (Eq.), 2351 s (non-Eq.) per iteration.

Figure 2: N -terminal setups are now possible in the TranSIESTA-code (N ≥ 1).

Effect of electrochemical decoration of silver nanoparticles on arsenic detection performance Anamaria Baciu, Aniela Pop, Florica Manea Politehnica University of Timisoara, Romania anamaria.baciu@upt.ro; florica.manea@upt.ro Abstract Silver functionalized-synthetic zeolite-carbon nanotubes-epoxy composite (AgSZ-CNT) electrode was obtained by two-roll mill procedure and tested for arsenic (III) detection in water using anodic stripping voltammetry (ASV) technique. In order to improve the electroanalytical parameters for arsenic (III) detection, silver nanoparticles were electrodeposited under potentiostatic conditions on AgSZ-CNT electrode surface, resulting a new electrode named (Ag)AgSZ-CNT. Both electrodes were tested for arsenic (III) detection and better results were reached using (Ag)AgSZ-CNT electrode. AgSZ-CNT was obtained by two roll mill procedure using multi-wall carbon nanotubes (MWCNTs) with average diameter of 9.5 nm and average length of 1.5 Č?m, purchased from Nanocyl, Belgium. Syntetic A-type zeolite (SZ) was prepared using natural zeolite from Mirsid, Romania, with 68% wt. clinoptilolite as a silicon source and sodium aluminate as aluminium source, as we previous described [1]. The detailed description of carbon nanotubes based composite electrode preparation was also, previously reported by our group [2]. The electrodeposition of silver nanoparticles on electrode surface was achieved by maintaining the electrode potential at value of -0.4 V/SCE in 0.1 M AgNO3 solution for three seconds, which represents the optimum electrodeposition conditions. This optimum electrodeposition conditions was established in direct relation with the best useful signal for the detection of 1 mM arsenic (III). Electrochemical measurements were carried out using an Autolab PGSTAT 302N (Metrohm Autolab, The Netherlands) controlled with GPES 9.4 software and a threeelectrode cell, with a saturated calomel reference electrode (SCE), a platinum counter electrode and the composite working electrode. The electrode surfaces were characterized morphologically by scanning electron microscopy (SEM) and SEM images are presented in Figure 1a and b. These silver-based electrodes were tested for arsenic (III) detection taking into account the demand for the development of fast and sensitive detection method. Arsenic (As) is a common trace element present in water from natural and anthropogenic sources, which is characterized by high toxic properties and as consequence, it exhibits a very negative impact on the human health. Most electrochemical methods involve anodic stripping voltammetry (ASV), which suppose two steps: first corresponding to reduction of arsenic (III) at the electrode surface for a certain time followed by the second step of electrochemically stripping from the electrode surface resulting a faradic response that is direct proportionally with arsenic concentration. The processes corresponding to these steps can be schematically represented by: Step 1- Deposition: As3++3e-oAs0 Step 2- Anodic stripping: As0 oAs3+ +3eCarbon nanotubes-based electrodes have been reported for anodic stripping voltammetric detection method for various heavy metals determination [3]. Functionalized-zeolite-modified electrodes represent an alternative to the carbon-based electrodes that do no exhibit electrocatalytic effect towards target analyte or to improve its performance. [4]. In this context, to combine the properties of carbon nanotubes and silver effect towards arsenic detection, AgSZ-CNT and (Ag) AgSZ-CNT electrodes were prepared. Cyclic voltammetry (CV), differential-pulsed voltammetry (DPV) and square-wave voltammetry (SWV) techniques were used to elaborate the ASV-based detection schemes of arsenic (III) from aqueous solution. In Figure 2a and b are presented series of CVs recorded at both electrodes.The deposition potential of -0.4 V/SCE for the deposition time of 120 seconds represent the optimum operating conditions for the arsenic deposition step prior to the all anodic stripping voltammetric experiments. SWV technique operated at 0.2V modulation amplitude, 0.02 V step potential and 10 Hz frequency allowing the best sensitivity and the presence of the silver nanopaticles on the electroe sensitivity enhanced the electroanalytical performance in relation with the sensitivity and the detection potential value (Table 1).

Table 1. The comparative electroanalytical performance for arsenic (III) detection for both electrodes Electrode type Technique Potential value Sensitivity Correlation coefficient, R2 -2 V / SCE mA / mMcm AgSZ-CNT DPV 0.10 0.191 0.974 SWV 0.14 2.558 0.981 (Ag)AgSZ-CNT DPV 0.05 22.455 0.981 SWV 0.09 23.254 0.996 Acknowledgments This work was partially supported by the strategic grant POSDRU/159/1.5/S/137070 (2014) of the Ministry of National Education, Romania, co-financed by the European Social Fund â&#x20AC;&#x201C; Investing in People, within the Sectoral Operational Programme Human Resources Development 2007-2013,and partially by the PNII-PCCA-60/2012 (WATUSER) and PN-II-ID-PCE 165/2011 Grants. References [1] C. Orha, A. Pop, C. Lazau, I. Grozescu, V. Tiponut, F. Manea, Journal of Optoelectronics and Advanced Materials 13 (2011), 544. [2] A. Remes, A. Pop, F. Manea, A. Baciu, S. J. Picken, J. Schoonman, Sensor. 12 (2012) 7033. [3] J.H. Yoon, G. Muthuraman, J.E. Yang, Y.B. Shim, M.S. Won, Electroanalysis, 19, (2007), 1160. [4] A. Baciu, A. Remes, A. Pop, F. Manea, G. Burtica, The17th International Symposium on Analytical and Environmental Problems, Szeged, 19, September, (2011). 339. Figures

1.0

0.8

0.8 -2

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0.6

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-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4

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Fig. 2. CVs recorded composite electrode in 0.09 M Na2SO4+ 0.01 M H2SO4 supporting electrolyte (curve 1) and in the presence of 0.2- 1.2 mM As concentration range(curves 2- 11) with a preconditioning of electrode at -0.4 V/SCE at deposition time of 120 s, potential scan rate: 0.05 Vs-1, potential range: -0.5 to +0.4 V/SCE, at: a) AgSZ-CNT, b) (Ag)AgSZ-CNT electrodes

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Nanoparticulated ceria dispersed over silica: XPS study of the redox deactivation process Ginesa Blancoa, Ismael Cabezaa, Lorena Gonzáleza, José Mª Pintadoa, Mariana Rochab, Clara Pereirab, Cristina Freireb a Departamento de Ciencia de Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, Cádiz, Spain b REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Portugal ginesa.blanco@uca.es Abstract Cerium oxide is widely employed in many technological applications. Despite cerium is relatively abundant in the earth crust, its ores are quite scarce, and limited to few countries in the world. This fact, together with the more and more extended applications of ceria, its prices have increased in the past years. Finding ways to decrease ceria content, mantaining good properties is a main goal in many recent studies about ceria. One of the most important applications for ceria and ceria-based oxides, concerns their use as catalysts and catalytic supports [1]. It is well known that ceria redox properties can be modulated by changing its particle size. Dispersion of ceria on a proper support can be used to decrease ceria content of the catalysts keeping or even improving its redox properties. In this work, we have dispersed small ceria nanoparticles over porous silica nanoparticles. Redox behaviour of this material, as well as its stability when submitted to high temperature treatments has been studied. Porous silica nanoparticles (average diameter 40 nm) were used to prepare two different samples by chemical precipitation of cerium (III) nitrate using HMT [2]. Sample CS-1 was prepared by this method, with a Ce/Si molar ratio of 0.23. For sample CS-2 an anionic surfactant (SDBS, Sodium Dodecyl Benzene Sulfonate) was also added, and its Ce/Si molar ratio was set to 0.39. TPR-MS studies were performed in an experimental device coupled to a Thermostar GSD301T1, quadrupole mass spectrometer from Pfeiffer, using a 5% H2/Ar flow. Electron Microscopy studies were performed in a JEOL2010F TEM/STEM microscope. The electron microscopy sample grid was prepared by depositing the sample powder directly onto holey-carbon Cu grids. A self-supported wafer of the ceria-silica sample was successively subjected to a series of reducing and oxidizing treatments, and investigated by XPS on a Kratos Axis Ultra DLD instrument equipped with a catalytic cell allowing a clean transfer of the pretreated samples to the analytical chamber. Spectra were recorded with monochromatized AlKĮ radiation (1486.6 eV). Surface charging effects were compensated by using the Kratos coaxial neutralization system. The binding energy (BE) scale was calibrated with respect to the C 1s signal at 284.8 eV. Spectral processing was performed with CasaXPS software. The electron microscopy study of the ceria-silica samples (not shown) indicates that ceria is well dispersed on the porous silica as nanoparticles with an average size of about 1-1.5 nm, both on the external surface of the silica as well as inside the pore structure. The redox behaviour of the samples was studied by TPR. Fig. 1 shows the reduction profile for CS-1, CS-2 and a pure ceria sample. A first TPR performed on the CS-1 and CS-2 samples (thick lines), shows that for both samples the reducibility is significantly enhanced with respect to pure ceria. After this TPR experiments, the ceria-silica samples were reoxidized and then submitted to a new TPR experiment (thin lines in Fig.1). This second TPR shows a strong deactivation of the ceria-silica samples, as there is a strong reduction in the TPR are for CS-1, and a complete disappearance of the TPR signal for CS-2. XPS studies were performed on the samples, after being submitted to successive reduction and reoxidation treatments. After each treatment, surface Ce(III) content was measured. Due to the small size of ceria nanocrystals, XPS data is representative of the behaviour of all ceria contained in the samples. For sample CS-1, Fig. 2 shows Ce(III) evolution throughout the successive reduction at temperatures ranging from 350 to 900ºC. After each reduction %Ce(III) was measured by XPS, then the sample was reoxidized at 350ºC, and the %Ce(III) measured again. Fig. 2 shows how Ce reduction degree increases when increasing reduction temperature, reaching 100% reduction after reduction treatment at 700 and 900ºC. The amount of remaining Ce(III) after reoxidation treatment at 350ºC increases gradually after each reduction/reoxidation cycle, being as high as 86% after the redox cycle at 900ºC. A further reoxidation at 600ºC is only able to decrease remaining Ce(III) to 76%, but complete recovery of Ce(IV) could be reached after reoxidizing at 800ºC. In the case of CS-2 sample, a similar behaviour was observed, remaining all cerium as Ce(III) after reduction at 900ºC and reoxidation at 350ºC, in well agreement with the second TPR in Fig. 1. In conclusion, two ceria-silica samples, with highly dispersed ceria, were prepared. Both samples exhibit better reducibility than bulk ceria. However, thermal deactivation was observed, as a blockage of cerium

in the trivalent state. This deactivation proceeds gradually as reduction temperature is increased, and can be reverted by reoxidation at high temperature. Financial support from the Ministry of Economy and Competitiveness of Spain (Project CSD200900013), the Spanish-Portuguese Bilateral Cooperation through Projects PT2009-0126 (Spain) and REF E-72/10 (Portugal), and the Junta de AndalucĂa (Groups FQM-110 and FQM-334) is acknowledged. References >1@ A. Trovarelli (Ed.) Catalysis by Ceria and Related Materials. Imperial College Press (2002) [2]

X. Zhao, R. Long, Y. Chen, Z. Chen. Microelectron. Eng. 87 (2010) 1716

Figures

Figure 1. TPR-MS for the reduction under H2/Ar of the ceria-silica samples. The thick line corresponds to a first TPR experiment, and the thin line to the second TPR. The reduction profile for a ceria massive oxide is included for comparison.

Figure 2. Ce(III) percentage measured by XPS for sample CS-1 submitted to the oxidizing and reducing treatments indicated in the figure.

Generation of Diode-Like Structures with Maxwellian Series Resistance in Electrically Stressed HoTiOx Thin Films a

J. Blasco , H. CastĂĄn , H. GarcĂa , S. DueĂąas , J. SuĂąĂŠ , M. Kemell , K. Kukli , M. Ritala , M. LeskelĂ¤ , a E. Miranda a

Dep. dâ&#x20AC;&#x2122;Enginyeria ElectrĂ˛nica, Universitat AutĂ˛noma de Barcelona, Cerdanyola del Valles, Spain b Dep. de Electricidad y ElectrĂłnica, Universidad de Valladolid, Valladolid, Spain c Dep. of Chemistry, University of Helsinki, Helsinki, Finland julio.blasco@uab.cat

Abstract It is generally accepted that the dielectric breakdown (BD) of a thin oxide layer in a metal-insulatormetal structure is the consequence of a local accumulation of defects generated for example by the application of electrical stress. This accumulation of defects leads ultimately to the formation of a filamentary path spanning the oxide layer with a consequent leakage current increase. Depending on the magnitude of the localized current, the BD event is often referred to as a soft (SBD) or hard (HBD) breakdown. While the distinction between SBD and HBD does not follow strict criteria, SBD has been reported to be well-described by an exponential dependence with the applied bias whereas HBD has been mostly associated with ohmic-like behavior [1]. Interestingly, the formation of such current paths is closely related to the so-called resistive switching (RS) effect, which corresponds to the reversible formation and dissolution of filamentary conductive structures caused by the application of electrical stimulii. However, the nature of the electron transport along these filaments is still an opened question. It is worth mentioning that RS is the physical mechanism behind the operational principle of Resistive RAM devices, which are believed to revolutionize the memory market in a near future. In this work, we have focused the attention on the post-BD current-voltage (I-V) characteristics of holmium titanium oxide (HoTiOx)-based MIM capacitors [2]. The HoTiOx film was grown by ALD (18.7nm) on TiN layers deposited on p-type Si substrates. The structures were electrical stressed so as to generate post-BD currents of increasing magnitude and the resulting I-V curves were fitted (Fig. 1) using a diode-like transport model [1,3-6]: (1) I I 0 exp D V IR 1

^ >

@ `

where I0>0 represents the diode saturation current, D>0 a constant, and Rt0 a series resistance. _V_ is the absolute value of V. The solution of Eq.(1) is given by:

DR 1W ^DI 0 R exp>D V

I 0 R @` I 0

(2)

where W is the Lambert function. Expression (2) can explain both the linear (HBD) and exponential (SBD) behavior (Fig.2): large currents are associated with small D values. The correlation among the model parameters was investigated and a strong correlation between R and I0 was found. Assuming 2 that I0 is proportional to the area of the narrowest section of the filamentary path (ar ), it is possible to demonstrate that R is consistent with a Maxwellian resistance (Ra1/r with r the radius of the constriction) [7] (see Fig.3). References [1] Miranda E, SuĂąĂŠ J, Electron transport through broken down ultra-thin SiO2 layers in MOS devices, Mic Rel 44 (2004) 1-23 [2] Kukli D, Kemell M, Dimri M, Puukilainen E, Tamm A, Stern R, Ritala M, Leskela M, Holmium titanium oxide films grown by atomic layer deposition, Thin Solid Films 565 (2014) 261-266 [3] Borghetti J, Strukov D, Pickett D, Joshua Yang J, Stewart D, Stanley Williams R, Electrical transport and thermometry of electroformed titanium dioxide memristive switches, J Appl Phys 106 (2009) 124504 [4] Tran X, Zhu W, Liu W, Yeo Y, Nguyen B, Yu H, A self-rectifying AlOy bipolar RRAM with sub-50-uA set/reset current for cross-bar architecture, IEEE Electron Dev Lett 33 (2012) 1402-1404 [5] Ortiz-Conde A, Garcia-SĂĄnchez F, Muci J, Exact analytical solutions of forward non-ideal diode equation with series and shunt parasitic resistances. Solid-St Electron 44 (2000) 1861-1864 [6] Blasco J, Ghenzi N, SuĂąĂŠ J, Levy P, Miranda E, Modeling of the hysteretic I-V characteristics of TiO2-based resistive switches using the generalized diode equation, IEEE Electron Dev Lett 35 (2014) 390-392

[7] Timsit R S, Electrical Conduction Through Small Contact Spots, IEEE Transactions on Components and Packaging Technologies 29 (2006) 727-734 Figures Fig. 1 – Experimental (thick solid lines) and fitting (thin solid lines) results using the diode-like model for post-BD conduction in HoTiOx. Fig. 2 – I0 YV Į correlation for the diode-like model. -1/2 Fig. 3 – R vs 1/I0 correlation for the diode-like model.

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Tuning the properties of epitaxial magnetite films by using different single crystal supports: Fe3O4(111)/Pt(111) vs. Fe3O4(111)/Ru(0001) $JQLHV]ND %RÄ&#x17E;-Liedke1, =\JPXQW 0LĂĄRV]2, Natalia Michalak2, Robert Ranecki2, 0LNRĂĄDM /HZDQGRZVNL1,2, 6ĂĄDZRPLU 0LHOFDUHk3, 7DGHXV] /XFLÄ&#x201D;VNL2, Stefan Jurga1 NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61- 3R]QDÄ&#x201D; 3RODQG Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60- 3R]QDÄ&#x201D; Poland 3 Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61- 3R]QDÄ&#x201D; 3RODQG E-mail: agnbos@amu.edu.pl, lewandowski@amu.edu.pl 1

Abstract Magnetite (Fe3O4) is a ferrimagnet and a semiconductor. Low-dimensional magnetite forms, such as nanoparticles or nanometer-thick films, often preserve the properties which makes them promising IRU DSSOLFDWLRQ DV Âłbuilding blockVÂ´ of nanoelectronic and spintronic devices. Epitaxial magnetite films were grown on many single crystal supports, including Pt(111) [1] and Ru(0001) [2]. The Fe3O4 films grown in (111) direction are particularly interesting, as they exhibit ~85% spin polarization [3]. The structure and properties of epitaxial magnetite can be rendered by the structure and properties of the single crystal support on which the film grows. This can be caused by many different factors, among which lattice mismatch and the corresponding epitaxial strain are of particular importance. We prepared few-nanometers-thick epitaxial magnetite films on Pt(111) and Ru(0001) and compared their structure and properties. The results indicate significant differences in the structure and properties of magnetite films grown on these two metal single crystal supports with slightly different crystal structure (fcc vs. hcp) and surface lattice consWDQW c YV c IRU 3W DQG 5X respectively). Acknowledgments This work was financially supported by the Polish Ministry of Science and Higher Education (Iuventus Plus programme, 2012-2015, grant No. IP2011 030071 Âą Ru(0001) part) and by the National Science Centre of Poland (SONATA programme, 2013-2016, grant No. 2012/05/D/ST3/02855 Âą Pt(111) part). S.J. acknowledges the support of the National Centre for Research and Development (PBS programme, 2012-2015, grant No. PBS1/A9/13/2012). M.L. would like to thank the Foundation for Polish Science for the START scholarship. References [1] W. Weiss, M. Ritter, Phys Rev. B, 59 (1999) 5201. [2] G. Ketteler, W. Ranke, J. Phys. Chem. B ,107 (2003) 4320. > @ 0 )RQLQ <X 6 'HGNRY 8 5Â GLJHU * *Â QWKHURGW /HFW Notes Phys., 678 (2005) 289.

Towards waferlevel fabricated CNT sensors ± Process improvements by length separation of single-walled carbon nanotubes 1

1,2

Simon Böttger , Sascha Hermann , Stefan E. Schulz 1

Technische Universität Chemnitz, Center for Microtechnologies, Reichenhainer Str. 70, 09126, Chemnitz, Germany 2 Fraunhofer Institute for Electronic Nano Systems (ENAS), Technologie-Campus 3, 09126, Chemnitz, Germany simon.boettger@zfm.tu-chemnitz.de Abstract Single-wall carbon nanotubes (SWCNTs) show unique and outstanding mechanical properties like high young¶s modulus and tensile strain. Furthermore depending on the chirality of the SWCNTs they show piezoresistive gauge factors up to 2900 [1], which is one order of magnitude higher than common silicon strain sensors. Therefore CNTs are promising candidates for mechanical, especially piezoresistive sensing. The aim of our project is a waferlevel fabrication of mechanical strain sensors based on the piezoresistive effect of horizontally aligned SWCNTs. Therefore it is mandatory to reproducible deposit homogeneous assemblies of CNTs which can be realized with the dielectrophoretic deposition (DEP) as already shown by our group on waferlevel [2]. Furthermore a sufficient CNT length distribution is required in order to prevent chain formation in the transistor channel and to afford reliable electrical and mechanical contacting. Therefore the pre-selection of the CNT raw material according to length is a prerequisite for a successful waferlevel integration of CNTs into field effect transistors (FETs) which is the basic element in a piezoresistive transducer. This pre-selection is realized by size-exclusion chromatography (SEC) as already presented in literature [3]. Moreover we integrated length separated SWCNTs in FETs and investigated their performance The first step is the preparation of a homogeneous CNT dispersion by sonification and centrifugation of SWCNTs dispersed in a surfactant solution of sodium monohydrate deoxycholate (DOC) and deionized water. After that we perform the length separation with SEC by using a single column setup filled with a porous particle gel of a certain pore size. By applying a constant flow rate ĭ to the column, an interaction between dispersed SWCNTs and the gel particles leads to a different retention time depending on the length of the tubes separating them by length. Finally fractions of length separated CNT dispersions are collected and furthermore characterized with UV-Vis-NIR and Raman spectroscopy. Afterwards the CNTs were deposited by DEP on Pd electrode structures for length measurements of individual SWCNTs by atomic force microscopy (AFM) and scanning electron microscopy (SEM). From Raman and UV-Vis-NIR absorption spectra of length separated CNT fractions we extract some CNT-specific peak values. The aspect ratio (height/FWHM) of the RDPDQ *¶-peak and of the S11 transition peak from the absorbance spectra over the elution volume show a characteristic elution profile of the separation process itself (Fig. 1). Additionally the length separation was confirmed by AFM and SEM studies of CNTs assembled on pre-structured Pd electrodes (Fig. 2). As expected CNT length decreases with increasing elution volume. To quantify this results a statistical length analysis of over 200 CNTs from several fractions was performed and the length distribution for both original dispersions and length separated fractions were extracted (Fig. 3). The length distribution of the separated fractions was narrowed with respect to the original dispersions which give rise to homogeneous and well aligned CNT films. Moreover a systematic variation of different process parameters and their influence on the length distribution was done (e.g. flow rate and purity of raw material). Finally the CNTs were deposited into FET structures and the influence of separation on structural and electrical properties was investigated. References [1] Stampfer C., Jungen A., Linderman R., Obergfell D., Roth S., Hierold C., Nanoletters, 6(7) (2006) 1449. [2] Hermann S., Fiedler H., Haibo Y., Bonitz J., Loschek S., Schulz S.E., Gessner T., IEEE Proc. SSD, (2012). [3] Duesberg G.S., Burghard M., Muster J., Philipp G., Roth S., Chem. Commun., (1998) 435.

Figures

Figure 1: Characteristic elution profile of length separated carbon nanotube dispersions extracted from Absorbance and Raman spectra.

Figure 2: Assemblies of length separated carbon nanotubes deposited with dielectrophoretic deposition on Pd electrodes. Tube length decreases with increasing fraction number.

Figure 3: Length distribution of raw carbon nanotube material and length separated carbon nanotubes from different fractions.

Hybrid Graphene Nanocomposites for Use as Electrode in Energy Storage Devices 1

Zahilia Cabán-Huertas , Jullieth Suárez-Guevara , Pedro Gómez-Romero

Institut Català de Nanociència i Nanotecnologia, ICN2. Consejo Superior de Investigaciones Científicas (CSIC). Campus UAB, 08193 Bellaterra, Spain *pedro.gomez@cin2.es

Abstract Energy storage is increasingly recognized as a key technology to enable renewable electricity generation. Therefore, the search for the next generation of energy-storage materials and devices is 1 extremely important. The high energy density of rechargeable lithium batteries /,%¶V has transformed portable electronics over the past two decades. However, to meet the needs of new markets new generations of lithium batteries are required with increased energy and power density, improved safety, and lower cost. Supercapacitors 6&¶V are already used in a variety of applications. The power capability far exceeds that of lithium batteries but their energy density is low. If they are to make maximum impact, new generations are required with higher energy density and lower cost. Owing to its superior mechanical, thermal, and electrical properties, graphene is a perfect candidate to improve the performance of /,%¶V DQG 6&¶V. The design of hybrid materials based on graphene is an obvious path for the exploitation of multifunctional properties and the creation of synergies between the hybrid components. In principle the possible range of materials to be combined with graphene is huge and the choice should be based on the final properties sought for the composite. We will present an overview of our recent work dealing with the use of graphene for the synthesis of electrode materials to be used either in LIBs or SCs. In the first case electroactive but poorly conductive LiFePO4 is modified with graphene-like layers (Figure 1a). In the case of SCs, graphene not only provide a conducting substrate for the anchoring of electroactive polyoxomatalates (Figure 1b) but also contribute to energy storage leading to electrode materials with a dual storage mechanism (capacitive from graphene and 2 faradaic from the inorganic clusters). References (1) Choi, N.-S.; Chen, Z.; Freunberger, S. A.; Ji, X.; Sun, Y.-K.; Amine, K.; Yushin, G.; Nazar, L. F.; Cho, J.; Bruce, P. G. Angewandte Chemie International Edition 2012, 51, 9994. (2) Suarez-Guevara, J.; Ruiz, V.; Gomez-Romero, P. Physical Chemistry Chemical Physics 2014, 16, 20411. Figures

Figure 1 (a)LiFePO4 K\EULG FRPSRVLWH WR XVH DV FDWKRGH LQ /,%¶V E hybrid supercapacitor electrode by 2 a novel reduction of GO with simultaneous incorporation of polyoxometalate.

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

Gold Nanoparticles Supported on Carbon Materials for Cyclohexane Oxidation a

b,c

S.A.C. Carabineiro , L.M.D.R.S. Martins, , M. Avalos-Borja , J.G. Buijnsters , A.J.L. Pombeiro , J.L. a Figueiredo a LCM - Laboratory of Catalysis and Materials - Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal b Chemical Engineering Departament, ISEL, Rua Conselheiro EmĂdio Navarro, 1959-007 Lisboa, Portugal c Centro de QuĂmica Estrutural, IST, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal d Centro de Nanociencias y NanotecnologĂa, Universidad Nacional AutĂłnoma de MĂŠxico, A. Postal 2681, Ensenada, Baja California, 22800, Mexico (on leave at Instituto Potosino de InvestigaciĂłn CientĂfica y TecnolĂłgica (IPICyT), Division de Materiales Avanzados, San Luis Potosi, S.L.P., Mexico) e Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Leuven, Belgium scarabin@fe.up.pt Hydrocarbons, particularly alkanes, are interesting compounds as main constituents of natural oil and gas and their C-H bond(s) can be converted to C-OH or C=O functional groups leading to the production of more valuable products for fine chemical synthesis. However, activation of the former bonds in such stable compounds is difficult, which still prevents their generalised use in the direct synthesis of added value chemical products [1]. An example with high industrial significance concerns the oxidation of cyclohexane to cyclohexanol and cyclohexanone (Scheme 1) that are important reagents for the production of adipic acid and caprolactam, used for the manufacture of nylon. The industrial process uses a homogeneous cobalt species as catalyst and dioxygen as oxidant at a considerably high temperature (150 ÂşC). However, the oxidation products are formed in low yields (5-12%) to achieve a good selectivity (ca. 80-85 %) [1], and thus the need for more effective systems under milder reaction conditions has been recognised [1].

Scheme 1 Âą Oxidation of cyclohexane to cyclohexanol and cyclohexanone.

*ROG FDWDO\VWV DUH FXUUHQWO\ D ÂľÂľKRW WRSLFÂśÂś RI UHVHDUFK DV WKH\ show application in many reactions of industrial and environmental importance [2]. Several variables have been considered as important factors influencing the chemistry, structure and catalytic activity. Among them are the method of preparation, the nature of the support and, particularly, the gold nanoparticle size [2]. Gold (1 wt.%) was loaded on several types of carbon materials: activated carbon (AC), polymer based carbon xerogels (CX with smaller mesopore width and CXL with larger width), multi-walled carbon nanotubes (CNT), nanodiamonds in liquid (NDLIQ) and powder (NDPW), microdiamonds (MD), graphite (GR) and silicon carbide (SC) using two different methods (sol immobilization, COL, and double impregnation, DIM). The obtained Au/carbon materials were used as catalysts for the oxidation of cyclohexane to cyclohexanol and cyclohexanone, with aqueous H 2O2, under mild conditions. The most active catalyst was prepared by supporting gold nanoparticles on carbon nanotubes by the sol method, achieving an overall turnover number of ca. 171 and an overall yield of 3.6 % after 6 h reaction time (Figure 1). These values are comparable to the industrial process (that uses Co catalysts and high temperature), but were obtained at ambient temperature with considerable low loads of catalyst (Au catalyst to substrate molar -3 ratio always lower than 1 x 10 ), which is of relevance for establishing a greener catalytic process for cyclohexane oxidation. Moreover, a very high selectivity towards the formation of cyclohexanol and cyclohexanone was achieved, since no traces of by-products were detected. Catalyst recycling was tested up to six consecutive cycles for the most active catalytic system (gold deposited on carbon nanotubes by sol immobilisation), and it was found that the catalyst maintains almost the original level of activity after several reaction cycles (there was only a 6% drop in activity after the sixth cycle) with a rather high selectivity to cyclohexanol and cyclohexanone and with no catalyst leaching.

The differences in catalytic performance of the studied Au/carbon catalysts can be explained in terms of gold nanoparticle size (Figure 2), the lower sizes generally showed improved activity, as expected [1,2].

Figure 1 ± Dependence of the overall turnover number (moles of cyclohexanol + cyclohexanone per mole of Au nanoparticles loaded on the carbon material) of the products on the type of support and impregnation method (COL (Ŷ) and DIM (Ŷ)). Reaction conditions: CH3CN (3.0 mL), cyclohexane (5.0 mmol), n(Hpca)/n(catalyst) (50), room temperature, 6 h. Au/CNT-COL

50 nm

Au/CNT-DIM Au/AC-COL

20 nm

Figure 2 ±HAADF micrograph of Au/CNT-COL (left). HRTEM images of Au/CNT-DIM (middle), Au/AC-COL (right) Gold nanoparticles are seen as darker spots on HRTEM images and as bright spots on HAADF micrograph. Acknowledgments: This work was supported by Project PEst-C/EQB/LA0020/2013, financed by FEDER through COMPETE ± Programa Operacional Factores de Competitividade, and by FCT ± Fundação para a Ciência e a Tecnologia, and co-financed by QREN, ON2 and FEDER (Project NORTE-07-0124-FEDER-0000015). The authors are also grateful to FCT and FEDER for the financial support through projects PEst-C/EQB/LA0020/2011, PEstOE/QUI/UI0100/2011, PTDC/EQU-EQU/122025/2010, PTDC/QUI-QUI/102150/2008 and PTDC/QUIQUI/100682/2008 in context of COMPETE program and Investigador FCT program (SACC), as well as the Executive Research Agency of the European Union for funding under the Marie Curie IEF grant number 272448 (JGB). Dr. Nicolas Cayetano is acknowledged for help with TEM work, Gladis Labrada and Ana Iris Peña for SEM work, and LINAN for providing access to microscope facilities. The authors are also thankful to Dr. Carlos M. Sá (CEMUP) for assistance with XPS. References [1] S.A.C. Carabineiro, L.M.D.R.S. Martins, J.G. Buijnsters, M. Avalos-Borja, A.J.L. Pombeiro, J.L. Figueiredo, Applied Catalysis A: General, 467 (2013) 279±290. [2] S.A.C. Carabineiro, D.T. Thompson (2010), In: Gold: Science and Applications, Eds. C. Corti, R. Holliday, CRC Press, Taylor and Francis Group, New York, pp.89-122 (ISBN-978-1-4200-6523-7).

The hidden influence of the flux of gas on the growth of graphene layers by low pressure chemical vapor deposition S. Chaitoglou, A. Musheghyan, V-M Freire, M.Reza Sanaee, E. Pascual, J-/ $QG~MDU DQG E.Bertran *UXS )(0$1 'HSDUWDPHQW GH )tVLFD $SOLFDGD , Ă&#x2018;SWLFD ,1 8%, Universitat de Barcelona, 0DUWt L )UDQTXqV %DUFHORQD 6SDLQ

stefanoschaitoglou@ub.com Abstract The extraordinary properties of graphene make it one of the most interesting materials for future applications in electronics, optics and structural materials. Among the various synthetic methods, chemical vapor deposition (CVD) is the one that opens the possibility to obtain large areas of monolayer graphene without defects. To achieve this, it is important to find the appropriate conditions for each experimental system. In particular, for our CVD reactor working at low pressure, important factors appear to be the pretreatment of the copper substrate, considering both its cleaning and its annealing before the growing process and the flows of methane and hydrogen. Copper substrate is usually exposed to methane, hydrogen and argon gases and, WKH JURZWK LV WDNLQJ SODFH DW Â&#x192;& In this work, we have focused on the study of the methane and the hydrogen flows to control the production of mono and bilayer graphene. In particular, we observe that different hydrogen flows can result in the growth of smooth hexagonal graphene domains or random formed domains. This is a result of the etching effect that hydrogen performs on the growing graphene. It is important, therefore, to study the moderated presence of hydrogen, which allows to form flat hexagonal domains. Structural characterization was performed by Raman spectroscopy and morphological by scanning electron transmission microscope. The characteristic 2D Raman peak showed a ratio 2D/G > 1 owing to the formation of mono or bilayer graphene. The SEM exploration provided characteristic shape and size of the graphene domains as a result of the etching process that the different H 2 fluxes produce. Further investigation needs to be done in order to achieve the synthesis of graphene domains large enough to be use full for applications. References Terasawa, Tomo-R 6DLNL .RLFKLUR ÂłGrowth of graphene on Cu by plasma enhanced chemical vapor GHSRVLWLRQÂ´ CARBON, 50(3), 2012, 869-874 /L ;XHVRQJ 0DJQXVRQ &DUO : 9HQXJRSDO $UFKDQD HW iO Â´ Large-Area Graphene Single Crystals Grown by Low-Pressure Chemical Vapor Deposition of Methane on CopperÂ´ -2851$/ 2) 7+( AMERICAN CHEMICAL SOCIETY , 133 , 9 ,2011, 2816-2819 A.C.Ferrari et al, Raman Spectrum of Graphene and Graphene Layers, PRL 97, 2006,187401 S.M.Kim et al, ÂľÂś7KH HIIHFW RI FRSSHU SUH-FOHDQLQJ RQ JUDSKHQH V\QWKHVLVÂśÂś, Nanotechnology 24 (2013) 365602 (7pp) I. Vlassiouk et al, ÂľÂś*UDSKHQH 1XFOHDWLRQ Density on Copper: Fundamental Role of Background 3UHVVXUHÂśÂś,J. Phys. Chem.C 117,2013,18919 Zhang et al, ÂľÂś Hydrogen-induced effects on the CVD growth of high-quality graphene structuresÂśÂś Nanoscale,5, 2013,8363

Figures

Figure1RAMAN spectrum of a graphene layer

Figure 2. Typical hexagonal graphene domain of sample (14G14), grown under 60 Pa of methane, H2 and Ar PL[WXUH GXULQJ PLQ DW Â&#x17E;&

Figure 3 Randomly etched formed graphene domains, as a result of the H2 rich gas mixture and similar conditions shown in Figure 2. (sample 14G1101)

Figure 4. Reactor scheme

Figure 5 Plot of the oven temperature vs. time during the growth of graphene. The pressure and gas flow events during synthesis have been indicated in the graph.

Core-shell structured CNT@CNT for the application of Supercapacitor Xuecheng Chen, RyszardJ.Kalenczuk, Ewa Mijowska Institute of Chemical and Environment Engineering, West Pomeranian University of Technology, ul.Pulaskiego10, Szczecin, Poland xchen@zut.edu.pl Abstract [1,2] Here, we reported a facile method to synthesize core/shell structured CNT@CNT . They were fabricated by templating method to form mesoporous silica coated on CNT(CNT@m-SiO2) and then hydrothermal reaction to coat carbon on CNT@m-SiO2 template(CNT@m-SiO2@CNT). After removing the silica template, CNT@CNTs were obtained. Both of the core and shell were formed by graphitic layers analogous to multiwalled carbon nanotubes. The formation of this core/shell structure resulted in the enhancement of specific surface area. The electrochemical properties of the CNT@CNT s [3,4] composites as electrode materials for supercapacitors were investigated . References [1] H.Q Li, C.S Ha, Il. Kim, Nanoscale Res Lett, 4(2009)1384±1388. [2] M. Zhang, X. H. Zhang, X. W. He, L. X. Chen, Y. K. Zhang, Materials Letters, 64(2010)1383±1386. [3] X.C. Chen, K. Kiezek, K. Wenelska, et. all. Chem. Asian J. 8(2013) 2627±2633. [4] K. Wilgosz, X.C. Chen, K. Kierzek. Nanoscale Res Lett, 7(2012) 269.

Figures

250 nm

Figure 1. TEM images of CNT@m-SiO2(a), CNT@m-SiO2@CNT(b), CNT@CNT(c, d).

Fabrication and Characterization of nano wire grid polarizers film by magnetic soft mold 1

Doo-sun Choi ,Sunghwan Chang ,Sang-Uk Jo ,Myung Yung Jeong

Korea Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-Ro Yuseong-Gu Daejeon 305-343, Republic of Korea 2 Department of Cogno-Mechatronics Engineering, Pusan National University, Geumjeong-gu Busan 609-735, Republic of Korea schang@kimm.re.kr Abstract We propose the fabrication of a 70 nm half-pitch wire grid polarizer(Figs.1,2,4) with high performance using magnetic soft mold. The device is a form of aluminium gratings on a PET(Polyethylene phthalate) substrate whose size of 3cm × 3cm is compatible with a TFT_LCD(Tin Flat Transistor Liquid Crystal Display) panel. A magnetic soft mold with a pitch of 70 nm was fabricated using two-step replication method(Fig.3). As a result, we get a NWGP(nano wire grid polarizer) pattern which has 70nm line width, 150nm depth, 140nm pitch, on substrate. The maximum and minimum transmittances of the NWGP at 800 nm were 80% and 10%(Fig.5), respectively. This work demonstrates is a unique cost-effective solution for nanopatterning requirements in consumer electronics components. References [1] XW Lin, W Hu, ZJ Wu, XK Hu, G Zhu, Journal of the Society for Information Display, 19(2011), 441± 446. [2] Young Jae Shin, Carlos Pina-Hernandez, Yi-Kuei Wu, Jong G Ok and L Jay Guo, Nanotechnology 23(2012), 344018. [3] Ahn S H and Guo L, Advanced Materials. 20(2008), 2044-2049. [4] K Asano, S Yokoyama, A Kemmochi, T Yatagai, Applied Optics, 53(2014), 2942-2948. [5] Thomas Weber, Thomas Ksebier, Adriana Szeghalmi, Mato Knez, Ernst-Bernhard Kley, Andreas Tnnermann, Nanoscale Research Letters, 6(2011), 558. [6] Yeon Sik Jung, Ju Ho Lee, Jeong Yong Lee and C. A. Ross, Nano Letter, 10(2010), 3722ė3726.

Figures

Fig 1. Schematic of polarization recycling principle using metal wire grid polarizer film.

Fig 2. Design of metal wire grid polarizer film.

Fig 3. Schematic of magnetic soft mold fabrication process.

Fig 4. SEM image top view of (a) metal deposition NWGP structure and (b)cross sectional SEM image of metal deposition NWGP grating with a pitch 140 ŕ¸Ş and grating height of 202 ŕ¸Ş.

Fig 5. Transmittance curves of an Al NWGP on PET substrates

Hybrid PbS QDs/silicon multispectral photodetector integrable with silicon ICs Dana Cristea, Paula Obreja, Adrian Dinescu National Institute for R&D in Microtechnologies, IMT-Bucharest Erou Iancu Nicolae 126 A, 077190 , Voluntari- Bucharest, Romania Email: dana.cristea@imt.ro Abstract Colloidal quantum dots QDs have been considered in the last years as a candidate material for photodetectors due to their tunability of optical absorption spectra through quantum size effect. Another important advantage is solution processibility that facilitates integration with a large variety of substrates. Different types of QD-based photodetectors have been reported [1-3]. Most of these photodetectors have been fabricated on transparent indium tin oxide (ITO)-coated glass substrates. Also IR photodetectors based on PbS QDs, integrable with silicon IC circuits have been recently obtained [4]. In this paper we propose a new structure: a hybrid PbS/Si diode that can achieve higher responsivities over a broader spectral range-from UV to SWIR. The device (fig. 1) consists of a Au/n-Si Schottky diode with digitated electrode in parallel with a p-PbS/n-Si heterojunction. PbS QDs film was deposited (in selected areas defined in PMMA) on top of Cr/Au/Si Schottky diode by multilayer spin coating. Large PbS QDs, 5.2 nm diameter, ED-P20-TOL-1500 from Evident Technologies, with first excitonic absorption feature at 1450 nm have been choose to address both the visible and SWIR spectra. The long ligand, oleic acid (C18), was replaced with a shorter one (C3), 3mercaptopropionic acid (MPA) in order to minimize inter-particle spacing and to improve the mobilitylifetime products of PbS CQD films, leading to increases in both the diffusion lengths of charge carriers and the efficiencies of PbS CQD based photodiode [6]. Layer-by layer deposition method was used to obtain continuous films. The process steps are: - spin-casting of PbS QDs solution (10 mg/ml) at 1000rpm/30s; - spin-casting of 10% MPA solution in methanol for 15 s at 2500 rpm; - rinsing two times with methanol. The process was repeated 7 times and than the PMMA was removed to open the pads. Further improvement of film quality and of device performance was achieved by functionalization of the Si substrate with cysteamine. I-V characteristics in dark and under illumination were recorded with the semiconductor characterization system Keithley 4200 SCS/C, connected to a dark Faraday cage, and monochromatic sources (laser diodes) with emission wavelength 370 nm, 1070 nm, 1200 nm, 1450 nm and 1550 nm respectively. We focused on UV and NIR ranges, to study the effect of PbS layer. Based on photocurrent measurements we calculated the responsivities at 5V reverse voltage. Fig. 2 shows the responsivities at 370 nm, 1070 nm, 1200 nm, 1450 nm and 1550 nm for a reference device (Au/Si Schottky diode) and for two hybrid devices PbS QDs/Si, with and without substrate functionalization with cysteamine. One can see that the PbS/Si devices have higher responsivities in UV and NIR ranges than the reference Si-based photodiode and an extended wavelength range in IR. The improvement is due to photocarrier generation in PbS and their separation due to the built-in electric field at the PbS/Si heterojunction. Further improvement of responsivity in IR range can be achieved using a metal-semiconductor-metal (MSM) - like configuration, as one can see in fig. 3. In this case the voltage applied between two interdigitated electrodes and the PbS film acts as a photoconductor. References [1] G. Konstantatos and E. H. Sargent, Infr. Phys. Technol., 54 (2011) , pp. 278–282. [2] E. J. Klem, J. S. Lewis, and D. Temple, Proc. SPIE, vol. 7660, Apr. 2010, p. 76602E-1, [3] E.Heves , Y. Gurbuz, IEEE Sensors Journal 14 (2014) pp. 816-820. [4] G. Sarasqueta, K. R. Choudhury, J. Subbiah, and F. So, Adv. Funct. Mater., 21 (2011) pp. 167–171, [5] E. Heves, C. Ozturk, V. Ozguz, .Y. Gurbuz, IEEE Electron Dev. Lett. 34 (2013), pp.662-664 [6] K.S. Jeong,.J.Tang, H. Liu, J.Kim, A. W. Schaefer,K. Kemp, L. Levina, X.Wang, S.Hoogland, R.Debnath, L.Brzozowski, E. H. Sargent, J.B. Asbury , ACS Nano, 6 (2012), pp. 89–99. Acknowledgements: The work was supported by the Romanian Program Space Technology and Advanced Research –STAR contract No. 14/2012

Figures

Responsivity [A/W]

Fig. 1. Schematic diagram of the hybrid PbS QDs/n-Si photodetector.

Wavelength [nm] Fig. 2. Responsivities in UV and SWIR for the reference Si Schottky diode and two hybrid devices PbS QDs/Si

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tĂǀĞůĞŶŐƚŚ ΀Ŷŵ΁ Fig. 3 Responsivity of the hybrid PbS/Si device in MSM configuration compared with the configuration with PbS/Si heterojunction.

Functional ZrO2 nanoparticles as lubricant additives. Jorge Espina Casado, Humberto Rodiguez-Solla, Antolin Hernández Battez, Rosana Badía Laíño, Marta Elena Díaz García Department of Physical and Analytical, University of Oviedo, Av. Julián Clavería 8 33006, Oviedo, Spain medg@uniovi.es Abstract In the last decade considerable effort has been devoted to the development of organic-inorganic hybrid lubricants by introduction of different kind of nanoparticles within the base oil. When nanoparticles are added in small concentration a significantly improved performance of the base oil is observed: reduction of interfacial friction and improvement of the load-bearing capacity of the parts [1-4]. However, when using raw nanoparticles there are some withdraws that limit any benefit: due to their high surface energy nanoparticles tend to aggregate, some are difficult to disperse and tend to sediment. Some of disadvantages can be solved or minimized by surface functionalization of the nanoparticles. In fact, it has been demonstrated that surface grafting of nanoparticles using amphiphilic organic chains is an effective way to get stable dispersions and strengthen the tribological properties of the oil. In this work, we describe the functionalization of ZrO2 nanoparticles with three different long-chain hydrocarbons, octanoyl chloride, decanoyl chloride and palmitoyl chloride. The reaction (Figure 1) between nanoparticles and the different organic chlorides was run in dichloromethane under inert atmosphere (N2). Triethylamine reacted first with the organic chloride and formed an intermediate reactive which then reacted with the ZrO2 nanoparticle. After 24 hours reaction the yellow suspension formed was thoroughly cleaned with a mixture of solvents. The synthetized nanoparticles were characterized by FTIR spectroscopy and RMN. The nanoparticles were dispersed in a lubricant base oil using an ultrasonic probe. The stability of the corresponding suspensions was studied and results compared with those obtained using nonfunctionalized nanoparticles. The different factors affecting the sonication process were studied using a two level experimental design. Nanoparticles concentration, time and sonication cycle resulted to be significant. The stability was measured using a Turbiscan AGS equipment. The variation of the backscattering and transmission indicated the stability of the suspension. In Figure 2, we can observe that, after 24 h, the backscattering variations on the top and on the bottom of the measurement cell were lesser for decanoyl grafted ZrO2 nanoparticles than for the raw ones. These results are highly promising and work aimed to use these functional nanoparticles as lubricant additives for industrial applications is currently in progress. References [1] Da Jiao et al, Applied Surface Science 257, The tribology properties of alumina/silica composite nanoparticles as lubricant additives (2011) 5720-5725 [2] Zhang M et al, Tribol. Int 42, Performance and anti-wear mechanism of CaCO3 nanoparticles as a green additive in poly-alpha-olefin (2009) 1029-1039 [3] C. Shahar et al, Langmuir 26, Surface functionalization of WS2 Fullerene-like nanoparticle (2010) 4409-4414 [4] D. Kim and L.A. Archer, Langmuir 27, Nanoscale organic-inorganic hybrid lubricants (2011) 30833094

Figures

Figure 1: Reaction conditions between ZrO2 nanoparticles and decanoyl chloride.

Figure 2: Backscattering variation after 24 hours on the top and the bottom of the measure cell

Fabrication and Characterization of Free-Standing Silver Nanorod Arrays for Photovoltaic Devices

Yuyi Feng, Kwang-Dae Kim, Sergej Andreev, Julian Reindl, Thomas Pfadler, James Dorman, Julian Kalb, Torsten Pietsch, Jonas Weickert, Lukas Schmidt-Mende University of Konstanz, Dept. of Physics, Universit채tstr. 10, 78457 Konstanz, Germany yuyi.feng@uni-konstanz.de Free-standing metal nanorod or nanowire arrays have attracted much attention in sensing, plasmonics, high density data storage, photocatalysts, photovoltaic devices, to name but a few. [1-5] In photovoltaics nanorod arrays are of particular interest for hybrid solar cells, whose nearoptimum architecture is proposed to consist of arrays of nanostructures providing huge interfaces, efficient light harvesting and one-dimensional charge transport pathways.[6] The most conductive metal, silver, scaled down to nanoarrays is assumed to become one of the most favorable structures for hybrid solar cells. However, large scale fabrication of such nanostructures is necessary in order to make them viable for application in devices. Here, we present large-area free-standing silver nanorod arrays on silicon substrates by anodic aluminium oxide template (AAO) - assisted electrochemical deposition. SEM images are shown below. These nanorod arrays will be characterized by TEM, UV-Vis, C-AFM, raman spectroscopy and Haze to investigate and optimize the electronic and optical properties. It is assumed that their application in hybrid solar cells will enhance the charge transport and light harvesting. This should ultimately lead to higher efficiencies. References [1] Xia Y, Yang P, Sun Y, Wu Y, Mayers B, et al. 2003. Advanced materials 15:353-89 [2] Jones MR, Osberg KD, Macfarlane RJ, Langille MR, Mirkin CA. 2011. Chemical Reviews 111:3736-827 [3] Yin A, Li J, Jian W, Bennett A, Xu J. 2001. Applied Physics Letters 79:1039-41 [4] Wang Y, Wang Q, Zhan X, Wang F, Safdar M, He J. 2013. Nanoscale 5:8326-39 [5] Musselman KP, Mulholland GJ, Robinson AP, Schmidt-Mende L, MacManus-Driscoll JL. 2008. Advanced Materials 20:4470-5 [6] Weickert J, Dunbar RB, Hesse HC, Wiedemann W, Schmidt-Mende L. 2011. Advanced Materials 23:1810-28

Figures

Fig.1 SEM images of silver nanorods embedding in AAO template: (a) top view and (b) cross-section view

Fig.2 SEM images of free-standing silver nanorod arrays on silicon substrate after dissolving the AAO template: (a) top view and (b) angle view

Evolution of electronic and magnetic properties of iron oxide and cobalt ferrite nanocrystals probed by synchrotron-based X-ray imaging and spectroscopy Arantxa Fraile Rodríguez1, Carlos Moya1, Nicolás Pérez1, Cinthia Piamonteze2, Xavier Batlle1, and Amílcar Labarta 1

Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia, Universitat de

Barcelona, 08028 Barcelona, Spain 2

Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland arantxa.fraile@ub.edu

Abstract Iron oxide-based nanoparticles (NP) have outstanding magnetic properties and promising applications for spin-filter devices, biomedicine, and catalysis. In addition to finite-size effects, a key issue for research is how the intrinsic magnetic properties of the individual particles are modified by their own electronic structure, chemistry, surface termination and crystallinity. In particular, the high-spin polarization predicted for Fe3O4 is limited experimentally by structural defects, cation and oxygen vacancies. For spinel ferrites such as CoFe2O4, the likely size-dependent cation distribution of the tetrahedral and octahedral sites in the close-packed oxygen structure may strongly affect the magnetic properties of the NP. By combining x-ray absorption spectra (XAS) with photoemission electron microscopy (PEEM), we analyze the electronic structure and chemical bonding of individual, pseudo-spherical Fe3-xO4 and CoFe2O4 NP in the size range of about 8 to 24 nm, synthesized by thermal decomposition of organometallic precursors [1] and deposited onto either grids or hydrophobic substrates. Both Fe3-xO4 and CoFe2O4 NP display high crystalline quality and macroscopic bulk-like magnetic properties down to about 5 nm [2,3]. The unique spectral features of the individual particles, such as resonance heights, chemical shifts, oxidation states of the Fe atoms and density of states for the core-hole state, as well as their XMCD asymmetry profiles, are correlated to variations in either the stoichiometry or the lattice geometry of their Fe and Co ions. A quantitative analysis of absorption spectra from single, covalentlybonded Fe3O4 NP of 15 and 24 nm deposited on bare and C-coated Si substrates, respectively, can be obtained from fitting the spectral characteristics (line-shapes and relative height of peaks L3A/L2, L3A/L3B) to a weighted sum of reference bulk spectra of different iron-oxide species. Interestingly, our data show that even in the case of the highest crystal quality particles, the variation of some synthesis parameters may significantly alter the cationic distribution and the uniformity of magnetic phases [4]. Furthermore, spatially integrated XAS and x-ray magnetic circular dichroism (XMCD) spectra, and element-specific hysteresis loops on mono-disperse assemblies of the above nanoparticles, have been performed at high magnetic fields (up to 6T) and variable temperature (2K-300K). By employing both the total-electron-yield and the total-fluorescence-yield modes, we are sensitive to both the surface and inner core regions of the nanoparticles. We will show first results on the evaluation of the cationic distribution, the magnetic contribution of the different magnetic ions, and on the mutual orientation of spins in the Fe and Co sublattices.

All the foregoing indicates the key role of surface chemistry on the physical properties of ferrimagnetic NP and, in turn, on the design of novel NP with optimized magnetic properties. This work was supported by Spanish MINECO (MAT2012-33037), Catalan DURSI (2009SGR856 and 2014SGR220), and European Union FEDER funds (Una manera de hacer Europa). A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme.

References [1] P. Guardia, N. Pérez, A. Labarta, and X. Batlle, Langmuir 26, 5843 (2010) [2] N. Pérez, F. Bartolomé, L. M. García, J. Bartolomé, M. P. Morales, C. J. Serna, A. Labarta, X. Batlle, Appl. Phys. Lett. 94, 093108 (2009) [3] X. Batlle et al, J. Appl. Phys. 109, 07B524 (2011) [4] X. Batlle, A. Labarta, and A. Fraile Rodríguez, McGraw-Hill Yearbook of Science & Technology, (2014) DOI: 10.1036/1097-8542.YB140220

Ge1-xSnx alloys synthesized by ion-implantation: from epitaxial thin films to crystalline nanostructures Kun Gao, S. Prucnal, C. Baehtz, R. Huebner, W. Skorupa, M. Helm, and Shengqiang Zhou Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Ion Beam Physics and Materials Research, P.O. Box 510119, 01314 Dresden, Germany k.gao@hzdr.de Abstract Group IV semiconductor alloys have drawn substantial attention for their potential applications in optoelectronic devices capable of integration with the existing silicon-based IC circuitry. Monocrystalline Ge1-xSnx alloys are promising for electronic and optical applications in virtue of their high carrier mobility and possibility of direct bandgap transition [1,2]. In this contribution we present the monocrystalline Ge1-xSnx thin film and nanostructure synthesized by ion implantation, by which the low solubility of Sn in Ge can be overcome. Sn was implanted into commercial Ge wafers at room temperature. After implantation, cross-sectional transmission electron microscopy (TEM) image reveals a 70 nm thick Sn-doped porous structure on 80 nm thick Sn-doped amorphous Ge layer. The implantation induced amorphized layer has been recrystallized after ultrashort thermal process. By nanosecond pulsed laser melting (PLM), high quality monocrystalline Ge1-xSnx thin films were obtained through a bottom-up liquid phase epitaxial process. On the other hand, solid phase recrystallization induced by millisecond flash lamp annealing (FLA) results in crystalline Ge1-xSnx porous nanostructures. Depending on the FLA condition, the structure can be polycrystalline or monocrystalline. Field emission scanning electron microscopy was applied to measure the surface morphology. High resolution transmission electron microscopy and Rutherford backscattering and channeling analysis confirmed the monocrystalline structure of the Ge1-xSnx layer. The crystallinity and the lattice expansion due to Sn doping were determined by X-ray diffraction and micro-Raman spectroscopy. Our investigation provides an efficient, IC-compatible technique to prepare high quality monocrystalline Ge1xSnx alloys. References [1] J. Kouvetakis et al., Ann. Rev. Mater. Res., (2006) 36, 497. [2] J. Mathews, et al., Appl. Phys. Lett., (2010) 97, 221912.

Figures

Fig. 1 (Left) <001> Random and channeled RBS spectra of as-implanted Ge1-xSnx with 0.5% Sn, and PLM treated Ge1-xSnx samples with Sn concentrations ranging from 0.5% to 1.5%. The inset shows the magnification of the random and channelling Sn signals from PLM treated samples with 1.0% Sn. (Right) Imaginary parts (Ä°2) of the complex dielectric function of PLM treated Ge1-xSnx alloys with different Sn concentrations determined by ellipsometry. The peaks E1 and E1 Çť1 marked in the figure correspond to transitions between the top two valence band and the lowest conduction band along the <111> direction

in the Brillouin zone. The clear redshifts of the E1 and E1 Çť1 with respect to increasing Sn concentration provides a direct evidence of the bandgap shrinkage as a consequence of the Sn-doping.

Fig. 2 SEM topography of Sn-implanted Ge. (left) as-implanted, (middle) after FLA, and (right) after PLM.

Fig. 3 Cross-sectional bright-field TEM micrograph and high-resolution TEM image (inset) of Snimplanted Ge. (left) as-implanted, (middle) after FLA, and (right) after PLM.

Transport mechanism and high-field electroluminescence of silicon nanocrystals/SiO2 superlattices B. Garrido,1 J. López-Vidrier,1 Y. Berencén,1 S. Hernández,1 O. Blázquez,1 S. Gutsch,2 D. Hiller,2 P. 3 3 3 2 Löper, M. Schnabel, S. Janz, M. Zacharias 1

MIND±IN2UB, Electronics Department, University of Barcelona, Martí i Franquès 1, E±08028 Barcelona, Spain 2 IMTEK, Faculty of Engineering, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, D79110 Freiburg, Germany 3 Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, D-79110 Freiburg, Germany bgarrido@el.ub.edu Abstract The size-dependent electronic and optical properties of silicon nanocrystals (Si-NCs) embedded in SiO2 matrix have been extensively studied during the last years, as they are fundamental to exploit 1,2 this system for light-emission or photovoltaic applications. Besides, to guarantee a good control of the NC size, the superlattice (SL) approach has demonstrated to be an excellent method for obtaining Si3 NCs with controlled size. Although the transport within these nanostructured and ordered systems have been studied in the recent past,4 some aspects of their electro-optical properties and its correlation with the charge transport mechanisms have not been fully studied. In the present work, SiOxN0.23/SiO2 SLs have been deposited on p-type c-Si substrate by means of plasma-enhanced chemical-vapor deposition (PECVD). Different structural parameters were varied from sample to sample, namely, the thickness of the SiOxN0.23 (tSRON) and oxide barrier (tSiO2) layers, and the Si excess within the Si-rich ones. A post-deposition annealing treatment was carried out at 1150 °C for 1 h in N2 ambient, to precipitate and crystallize the Si excess in the form of NCs. To investigate the electrical and electro-optical properties of the Si NC superlattices, a MOS device structure was fabricated by sputtering ITO on top and Al on the bottom (see Fig. 1). Further details on the sample and device fabrication can be found elsewhere.5,6 From an electrical point of view (see Fig. 2), a notorious increase in conductivity of the SL systems is found when tSRON and the Si excess increase, and tSiO2 decreases. In addition, the dependence of the electrical properties on voltage and temperature confirmed Poole-Frenkel (PF) as the main transport mechanism in our SL system. An electroluminescence (EL) study was carried out on the devices, showing a clear emission peak attributed to radiative recombination of electron-hole pairs within the NCs (see Fig. 3). On one hand, a blue-shifted emission is observed in devices containing thinner tSRON (i.e. with smaller NCs) and lower Si excess, attributed to the quantum confinement effect. On the other hand, the EL peak position remains unchanged at thinner tSiO2, indicating that the nanostructure morphology is held constant. Finally, the correlation between all our experimental observations support an EL excitation mechanism consisting of electron impact ionization on the Si NCs, which can be correlated to the PF transport through NCs (see Fig. 3). References [1] N. Lalic, J. Linnros, J. Appl. Phys., 80 (1996) 5971. [2] G. Conibeer, M. Green, R. Corkish, Y. Cho, E.-C. Cho, C.-W. Jiang, T. Fangsuwannarak, E. Pink, Y. Huang, T. Puzzer, T. Trupke, B. Richards, A. Shalav, K.-L. Lin, Thin Solid Films, 511 (2006) 654. [3] M. Zacharias, J. Heitmann, R. Scholz, U. Kahler, M. Schmidt, J. Bläsing, Appl. Phys. Lett., 80 (1999) 661. [4] S. Gutsch, J. Laube, A.M. Hartel, D. Hiller, N. Zakharov, P. Werner, M. Zacharias, J. Appl. Phys., 113 (2013) 133703. [5] A.M. Hartel, D. Hiller, S. Gutsch, P. Löper, S. Estradé, F. Peiró, B. Garrido, M. Zacharias, Thin Solid Films, 520 (2011) 121. [6] J. López-Vidrier, Y. Berencén, S. Hernández, O. Blázquez, S. Gutsch, J. Laube, D. Hiller, P. Löper, M. Schnabel, S. Janz, M. Zacharias, and B. Garrido, J. Appl. Phys., 114 (2013) 163701.

Figures

-4

-2

)

-2

)

Fig. 1. (Left) Cross-section scheme of the PECVD-deposited SiOxN0.23/SiO2 superlattiices for the present study. The sketch indicates the parameters that were varied, namely, the Si-rich oxynitride and oxide barrier layer thicknesses, tSRON and tSiO2, respectively, and the Si excess (x in SiOxN0.23). (Right) Device structure where the superlattices were embedded.

(a)

-1

(b)

SRON

-1

10 -3

Current Density (A·cm

t SiO2

[Si] -8

= 1 nm

exc

= 17 at.%

Current Density (A·cm

10 -6

SRON

t SRON

= 2.5 nm = 3.5 nm = 4.5 nm

-10

-5

SRON

= 3.5 nm

[Si]

= 17 at.%

exc

SiO2

-7

t t

SiO2

= 1 nm = 2 nm = 3 nm

t -5

SRON

SiO2

= 3.5 nm

= 1 nm

[Si]

= 27 at.%

[Si]

= 17 at.%

[Si]

= 12 at.%

exc

-7

exc

-9

-3

-1

Electric Field (MV·cm )

Fig. 2. Current density versus electric field characteristics of SiOxN0.23/SiO2 superlattices consisting of different Si-rich oxynitride layer thickness (left), different barrier thickness (middle) and different Si excess within the Si-rich layer (right).

t SRON

t EL

SRON

SiO2

= 3.5 nm

= 4.5 nm

= 17 at.%

exc

SRON

EL Intensity (arb. units) 0

= 1 nm

[Si]

(arb. units)

EL intensity, I

SRON

= 2.5 nm

|Voltage, V| (V)

t SRON

= 2.5 nm = 3.5 nm = 4.5 nm

14 1.2

1.4

1.6

1.8

2.0

2.2

Photon Energy (eV)

Fig. 3. (Left) Electroluminescence integrated intensity as a function of the applied voltage, showing an EL onset that depends on the Si-rich oxynitride layer thickness. (Middle) EL spectra corresponding to samples with different Si-rich oxynitride layer thickness, i.e. different NC sizes. (Right) Schematic energy band diagram of the studied superlattice under the presence of an external electric field, which shows the electron transport process and the EL mechanism. The changes in the band structure induced by the QD size reduction appear in red. Numbers indicate the different processes that take place: (1) electron injection through the ITO electrode; (2) trap-to-trap electron hopping; (3) thermallyactivated electron jump towards the extended conduction band states; (4) high kinetic energy electrons that take part in the impact ionization process; (5) promotion of the bound electrons within the QD valence band states to the QD conduction band (electron-hole pair generation); (6) radiative recombination of the electron-hole pair, yielding a photon (EL emission). Energies are not to scale. Image taken from Ref. [6].

Usage of oxygen-modified CNT for electrode material of an air-hydrogen fuel cell N.V. Glebova, A.A. Nechitailov, A.O. Krasnova Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 28 Politechnicheskaya St., Saint-Petersburg, Russia aan.shuv@mail.ioffe.ru Abstract The problem of efficiency of fuel cells is important recently with the introduction of this type of energy sources in a road transport. The efficiency problem of energy conversion of fuel cell consists of three main parts: the electrochemical activity of the electrode material in reactions creating potential, efficiency of mass transport and efficiency of charges transport. In order to increase the electrochemical activity and intensification of mass transport of cathode material of the hydrogen-oxygen fuel cell with proton conducting membrane by the authors was developed a material containing a short, pre- oxygen modified CNTs and platinum on carbon black (Pt/C). Having attached oxygen-containing groups of the atoms of the CNT provides Red-Ox activity of material with a high degree of reversibility. As a result, CNTs are an additional depolarizer, lowering the activation energy of the process of electrochemical reduction of molecular oxygen. However, the presence of short CNTs allows to obtain a equal by structure composite with larger porosity that improve mass transport. 1. Material (CNT and Pt/C) Electrode material was prepared by mechanically mixing and by ultrasonic homogenization of Pt/C and CNT. As Pt/C type was used commercial product E-TEK. The materials were characterized by scanning and transmission electron microscopy, EDAX, adsorption-structural analysis and helium pycnometry, FTIR-spectroscopy. Electrochemical behavior examined on a disk glassy carbon electrode in a 0.5 M sulfuric acid. CNTs produced by arc discharge between graphite electrodes in liquid hydrocarbon [1]. Unlike traditional arc technologies of CNT growth in the gas phase, the use of a liquid hydrocarbon phase substantially reduces the temperature of the CNT growth and increases the yield of CNT (close to 100%). Upon receipt of the CNT used technical graphite with low content of catalyst (iron impurities 0.03-0.2 wt.%). CNTs were subjected to plasma-chemical modification in high-frequency plasma discharge in argon. Then activated CNTs were prepared by nitrogen and oxygen treatment. When modifying CNT in frequency plasma closed hemispherical ends are primarily opened, defects in the surface structure are introduced; morphology, porous structure, surface active properties of CNTs are changed. Fig. 1 shows the spherical open ends, defects of side surfaces. For purification of metal impurities and partial oxidation with addition of oxygen-containing groups of atoms CNT treated with a solution of nitric acid (1:1) at a temperature of ~ 100C for 5 minutes, followed by repeated washing with water and drying. This treatment resulted in a decrease by approximately one order of content of metal impurities. 2. Electrochemical characteristics Red-Ox activity was ensured by a quinone-hydroquinone equilibrium. The presence of quinone groups were fixed according to the cyclic voltammograms and the characteristic absorption bands on the IR spectra. The presence of oxygen was also recorded by EDAX. Fig. 2 shows the cyclic voltammograms of CNT. Red-Ox process is characterized by high reversibility. Electroreduction kinetics of molecular oxygen was investigated on a rotating disk electrode using known relationships Koutecky Âą Levich. The results of measurement of densities of the kinetic currents by the rotating disk electrode showed a significant increase of kinetic current density of reduction of molecular oxygen in the case of introduction of the Red-Ox CNT additivies (Table). Measurements of components loads and thickness of active layers of samples with different contents of CNTs showed the porosity of the active layer linearly dependent on the content of the CNT. Degradation of the material under electrochemical influence was investigated. The mechanism of the influence of oxygen modified CNTs on the kinetics of oxygen electroreduction on platinum was proposed. It lies in the inclusion of the quinoneÂąhydroquinone Red-Ox equilibrium of the oxygen reduction. Table - Density kinetic currents at different electrode materials Material Specific current density, mA/cm2 (true surface Pt) at 450 mV E-TEK 0.23 E-TEK+CNT, 1:1 0.37

The CNTs electrically bonded to platinum CNT reduce (due to the hydroquinone groups) the oxygen adsorbed on it. This is reflected in the experimentally observed decrease in the oxygen coverage of platinum. The mechanism may be represented by the following sequence of equations:

References [1] G.Z.Paskalov; S.A.Krapivina; A.K.Filippov, US Patent 5,344.462. Sep. 6. 1994 Figures Fig. 1. TEM image of Plasmas CNTs: a) initial; b) after plasma modification (arrow shows open end)

a) Fig. 2 - Cyclic voltammograms of CNT

R-OH - e

i, mA

0,1

R=O

E =500 mV

0,0

R=O + e -0,1

-200

R-OH

200 400 600 800 1000

( P9 É¨ÉŹÉ§ $J $J&O

Acknowledgments This study was financially supported by the Russian Foundation for Basic Research (project no. 1408 31343 mol_a) and the Grant of the President of the Russian Federation - SS347.2014.2

Inelastic scattering and current-induced heating in graphene nanoconstrictions Tue Gunst, Jing-Tao Lü, Per Hedegaard, Mads Brandbyge Technical University of Denmark, DTU Nanotech, Kgs. Lyngby, Denmark tue.gunst@nanotech.dtu.dk Abstract The interplay between electronic current and phonon dynamics is an important and intriguing problem in nanoelectronics. For instance, this interaction is observed as contact disruption in graphene nanoconstrictions (GNCs), where the current-density can locally be very high, and is used for currentannealing of graphene edges [1]. Additionally, the structural response to the high bias can be studied by in situ transmission electron microscopy, making GNCs a good test bed for current-induced phenomena [2]. We have studied phonon dynamics in a GNC (Fig.1A) in the presence of electronic current using nonequilibrium Green’s functions (NEGF) and a semi-classical Langevin equation in combination with density functional theory (DFT) calculations [3]. We will argue that current-induced forces, different from Joule heating, will severely heat up such nanostructures. We find that the electronic transmission spectrum has several peaks with a width that is less than or comparable to typical optical vibrational frequencies of 0.2 eV (Fig.1B). We tune the Fermi-level, EF, to such a resonance (marked by a square) and find that the local current path runs through the center of the device (Fig.1C). The change in current paths when changing the energy illustrates the strong dependence on the electronic energy. Consequently, the interaction between current and local vibrations also depends strongly on energy. Therefore, we find that the probability of emitting a phonon can exceed that of absorbing one due to the strong variation in symmetry of the scattering states at EF ƫZ. This manifests itself in a negative vibrational damping and density of states (Fig.2A) and a corresponding nonlinear heating (Fig.2B). The effect is robust towards including the damping from the surrounding vibrations (Fig.2B full line) and it may limit the stability and capacity of GNCs to carry high currents. We also examine the inelastic scattering effects in the electronic current. The IV-characteristics can provide a spectroscopic fingerprint of localized vibrations in the system. We have recently developed a method that can include the rapid variation in the electronic spectrum with energy in inelastic tunneling spectroscopy (IETS) modelling [4]. Tuning the energy away from a resonance, the model gives results consistent with the wideband lowest order expansion (wbLOE) widely used in DFT modelling (Fig.3B). At resonance the spectrum changes quite remarkably with the novel extended LOE (exLOE) giving rise to several dip-peak features not present in the wbLOE model. Including the energy variation on the vibrational energy scale is important in electronic conductance and local heating modelling. This is especially true for graphene nanostructures where local vibrational frequencies approach 0.2 eV.

References [1] Qi et al. Nano Lett., 2014, 14 (8), pp 4238–4244. [2] F. Börrnert, A. Barreiro, D. Wolf, M. I. Katsnelson, B. Büchner,L. M. K. Vandersypen, M. H. Rümmeli, Nano Lett. 12, 4455 (2012). [3] T. Gunst, J.-T. Lü, P. Hedegaard, M. Brandbyge, Phys. Rev. B Rapid Comm. 88, 0161401 (2013). [4] J.-T. Lü, R. B. Christensen, G. Foti, T. Frederiksen, T. Gunst, M. Brandbyge, Phys. Rev. B Rapid Comm. 89, 081405 (2014).

Figure 1:

Figure 2:

Figure 3

Biocompatible peptide-based hydrogels as nanocarriers for a new antitumoral drug 1

Ana C. L. Hortelão , Bruno F. C. Hermenegildo , Helena Vilaça , Goreti Pereira , Bing Xu , 2 2 2 1 Maria-João R. P. Queiroz , José A. Martins , Paula M. T. Ferreira , Elisabete M. S. Castanheira 1

Centro de Física (CFUM), Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal Centro de Química (CQ/UM), Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal 3 Department of Chemistry, Brandeis University, Waltham, MA, 02454 USA alchortelao@gmail.com

The biocompatibility of peptide-based hydrogels make them ideal for biomedical applications such as drug delivery, biosensing, tissue engineering and wound healing [1-3]. However, the enzymatic hydrolysis of these materials can be regarded as a serious disadvantage. One way to increase the biostability of this type of hydrogels consists in using non-proteinogenic amino acids. In this work, several new hydrogelators were developed, containing a Naproxen or a Naphthalene group (Table 1), and their critical aggregation concentrations were determined by fluorescence. The influence of pH in the aggregation of these molecules was also investigated. TEM images revealed that these hydrogels contain entangled nanofibers with width ranging from 9 nm to 18 nm (Figure 1). The ability of these hydrogels to act as nanocarriers for an antitumoral drug was investigated. For that purpose, FRET (Förster Resonance Energy Transfer) assays were performed between the several hydrogels (acting as energy donors) and the new antitumoral fluorescent thieno[3,2-b]pyridine derivative 1 [4] (acting as energy acceptor). Donor-acceptor distances between 2.5nm and 3.5nm were determined. N

N S

N H

NH2 S

CO2CH3

Antitumoral thieno[3,2-b]pyridine derivative 1

The interaction between the new hydrogels and models of biological membranes was also confirmed by FRET. Lipid vesicles composed of egg lecithin/cholesterol 7:3 were used as membrane models, containing both the antitumoral compound 1 (as energy donor) and the lipid probe Nile Red (as energy acceptor). In this system, efficient energy transfer is observed. Upon interaction with the several hydrogelators, FRET vanishes, indicating a strong increase of the donor-acceptor distance. As the antitumoral compound tested here is especially active against human melanoma cell lines (GI50= =3.5 µM) [4], the results obtained here confirm the ability of these hydrogels to act as drug nanocarriers, being promising to the development of formulations for topical application. Acknowledgements: Foundation for the Science and Technology (FCT, Portugal), FEDER and QREN for financial support to the Research Centers, CFUM [Strategic Project PEst-C/FIS/UI0607/2013 (FCOMP-01-0124-FEDER-037291)] and CQ/UM [Strategic Project PEst-C/QUI/UI0686/2013 (FCOMP01-0124-FEDER-037302)]. FCT is also acknowledged for the PhD grant of H. Vilaça (SFRH/BD/7265/2010). References [1] F. Zhao, M. L. Ma, B. Xu, Chem. Soc. Rev., 38 (2009) 883. [2] X. Zhao, F. Pan, H. Xu, M. Yaseen, H. Shan, C. A. E. Hauser, S. Zhang, J. R. Lu, Chem. Soc. Rev., 39 (2010) 3840. [3] Y. Zhang, Y, Kuang, Y. A. Gao, B. Xu, Langmuir, 27 (2011) 529. [4] M.-J. R. P. Queiroz, R. C. Calhelha, L. Vale-Silva, E. Pinto, M. S.-J. Nascimento, Eur. J. Med. Chem., 45 (2010) 5732.

Table 1. Structure of the several hydrogelators Hydrogelator

Structure

Hydrogelator

Npx-Phe-ǻ3KH-OH

1-Naph-Phe-ǻ3KH-OH

Npx-Phe-ǻ$EX-OH

2-Naph-Phe-ǻ3KH-OH

Npx-Trp-ǻ3KH-OH

Npx: Naproxen Phe: Phenylalanine Abu: Aminobutyric acid Trp: Tryptophan Naph: Naphthalene

Structure

Figure 1. TEM images of Npx-Phe-ǻ3KH-OH (A) and Npx-Phe-ǻ$EX-OH (B).

Figure 2. Normalized emission spectra of Naproxen hydrogels in the presence of compound 1, exciting the hydrogels (Oexc=290 nm) and exciting only compound 1 (Oexc=360nm).

Synthesis of Transparent Conducting Hybrid Film of Metalliuc SWCNT and Graphene Wansoo Huh, Kwang-Hoon Lee Soongsil University, Department of Chemical Engineering, Dongjakku Sangdodong 511 Seoul, KOREA wshuh@ssu.ac.kr Abstract Organic electronic devices are receiving growing interest because of their potential to emplo y lightweight, low-cost materials in a flexible architecture. These devices contain organic semiconductor materials that can be uniquely tuned to enable properties and performance which can be competitive with entrenched inorganic electronics, while facilitating other exciting niche applications. Organic electronic devices such as organic photovoltaics and organic light emitting diodes require the use of a transparent electrode to allow photons to enter or exit the devices efficiently and to simultaneously allow the extraction or injection of charge carriers. Typically, indium tin oxide (ITO) is utilized as the electrode due to its excellent transparency throughout the visible spectrum, its relatively low sheet resistance, and its work function, which is compatible with the injection and collection of charge carriers in organic semiconductors. However, ITO may ultimately hinder the full market integration of organic electronics due to its increasing cost, lack of mechanical flexibility, chemical instability, and sustainability pertaining to the environment and material utilization. Therefore, alternatives for ITO in organic electronics are being pursued. Transparent electrodes comprised of carbon nanomaterials are an appealing choice as a surrogate for ITO in organic electronics because of the extraordinary electrical and mechanical properties these structures possess, and the demonstrated potential of state of the carbon nanomaterial films. As such, the research presented in this dissertation has been conducted to advance the goal of manufacturing SW CNT/graphene hybrid networks with transparent electrode properties that meet or exceed those of ITO. In order to fully realize the potential of SW CNT networks as a transparent electrode, monodisperse networks that leverage the electronic homogeneity of the film were investigated and discussed. Metallic SW CNT films were found to have superior optoelectronic properties in comparison to similarly processed SW CNT films. Electrical sheet resistance evaluation, and optical spectroscopy combined with a theoretical understanding of metallic and semiconducting SW CNT were employed to clearly describe the impact of structure on these films.

In this dissertation, SW CNT films were characterized with regard to the collective and individual properties of the SW CNTs that comprise the network. The insight gained from evaluation of intrinsic SW CNT properties was effectively leveraged to expand the present understanding of SW CNT networks to facilitate future SW CNT-based electrode development. References [1] Saito R., Fujita M., Dresselhaus G., and Dresselhaus M. S., Electronic structure of chiral graphene tubules, Appl. Phys. Lett., 2204-2206 (1992). 60 2. Iijima S., Helical microtubules of graphitic carbon, Nature, 56-58 (1991), 354 3. Iijima S., and Ichihashi T., Single-shell carbon nanotubes of 1-nm diameter, Nature, 603-605 (1993), 363

Figure: TEM image a) single layer of graphene, b) few layer of graphene.

Damage and Wear Resistance of Al2O3-CNT Nanocomposites Fabricated by Spark Plasma Sintering B.K. Jang*,1 and K.S. Lee2 1

High Temperature Materials Unit, National Institute for Materials Science (NIMS) 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan 2 School of Mechanical Engineering, Kookmin University, 861-1, Chongnung-dong, Songbuk-gu, Seoul, 136-702, Korea * JANG.Byungkoog@nims.go.jp

Abstract In this study, we prepare Al2O3-CNT (carbon nanotube) composites with different contents of CNT, 1~20vol% into the Al2O3 ceramics, for the purpose of improving damage and wear resistance. Al2O3CNT composites are obtained by spark plasma sintering in conditions of 1400~1600qC in vacuum and 30MPa~80MPa. Hardness evaluated by Vickers indentation shows that the hardness of Al2O3-CNT composites can be enhanced when the CNT addition is less than 5vol%. Toughness evaluated by Vickers indentation indicates that the toughness of the composites is comparable with that of an Al2O3 monolith. Hertzian indentations using a spherical indenter indicate the hard and elastic behavior of the composites by the addition of CNT. The wear rate and friction coefficients of the composites evaluated by the ball-on-disk method show that the composites represent low friction and reduced wear loss under constant contact load. The results indicate that the damage and wear resistance of Al2O3 ceramics can be enhanced by the addition of carbon nanotubes in optimum conditions.

1. Introduction CNT have attracted great interest because of their unique structural, electronic, physical, and thermal properties, such as high electrical conductivity, thermal conductivity, and elastic modulus[1,2]. It has been reported that CNT are 100 times stronger and 6 times lighter than steel. The electrical conductivity of CNT is better than that of copper (Cu), and the thermal conductivity of CNT is better than that of diamond. Therefore, CNT are added to metal, polymer, or ceramics to improve mechanical and thermal resistance or electrical conduction. Among these, CNT addition into engineering ceramics is expected to offer good damage and wear resistance, exhibited by the lower friction and damage absorption characteristics of carbon material. The goal of the present study is to improve the damage and wear resistance of alumina ceramics by the addition of CNT, considering only the content of CNT in the composites. The load-displacement curves were influenced by the CNT content in the composites. The hardness and toughness of Al2O3CNT nanocomposites were also affected by CNT contents, which, in turn, influenced the wear characteristics of the composites. 2. Experimental procedures Commercial starting powders of multi-walled CNT and Al2O3 (AKP-50, Sumitomo Co.) were used for fabricating the composites. The additions of CNT in the Al2O3 matrix are 1, 3, 5, 10, and 20vol%. Mixed powders were prepared by ball milling using high-purity Al2O3 balls with a 5mm diameter in a polyethylene pot with an isopropyl alcohol solution for 24h. The assembly of the graphite mold and mixed powders was set into the spark plasma sintering (SPS) apparatus (Syntex, Inc., Japan). The sintering temperature was 1400~1600oC in a vacuum of 10-2 Pa. Sintering was conducted for 20min at each sintering temperature under pressure of 30MPa, 60MPa, or 80MPa. After sintering, the samples were cooled to room temperature. Hertzian indentations were carried out to induce contact damages on the polished Al2O3-CNT composites using a universal testing machine (Instron 5567, UK). The top surfaces of each sample were contacted with a WC (tungsten carbide) spherical indenter with a radius (r) of 3.18mm, and the load was increased to P = 3000N and then unloaded to P = 0N. Vickers indentations using a sharp indenter were also carried out to evaluate hardness and toughness of the Al2O3-CNT composites using a microhardness tester (HM-114, Akashi, Japan). The surfaces of the composites were polished, and the indenter was driven and held for 5sec under P = 9.8N then unloaded.

3. Results and discussion Fig.1 shows typical micrographs of pristine CNT powders. Fig. 2 shows the representative mechanical behaviors of load-displacement curves for Al2O3-CNT composites containing different CNT contents under indentation loading by Hertzian indentation, using a WC ball with r = 3.18mm at maximum load P = 3000N. The composite was sintered at 1400oC under 60MPa. Indentation loadings cause fractures only in local areas and make it possible to predict the macroscopic mechanical properties.The loaddisplacement curve shows continuous curves during loading and unloading. It is noteworthy that the displacement after unloading is finished is smaller and that the slopes of the tangential curve increase as the CNT content increases in the composites. It is crack deflection and bridging to dominate the toughening in the composites as shown in Fig. 3. The fractured surfaces examined by SEM show many fractions of morphologies of CNT with high aspect ratio in the figure. Presumably, the crack propagates along the interface of the CNT, and crack bridging across the strong CNT occurs in the composites [3]. In addition, the pull out of CNT was observed in the Al2O3 matrix. Fig. 4 shows the comparison of average friction coefficients. The friction coefficients increase as the CNT content increases to 5vol%, then the coefficient is down to half one of 5vol% added one at 10vol% CNT content. The friction coefficient of 20vol% CNT-added composites is still lower than that of the Al2O3 sample. For all material cases, the composites containing 5vol% and 10vol% of CNT content sintered at 1500oC yielded lower friction [4].

Fig.1. Micrographs of CNT.

Fig.2. Plot of indentation load-displacement curves during Hertzian indentation.

1 Âľm

Fig.3. SEM showing fractured surface of Al2O3-2vol% CNT composites.

Fig.4. Friction coefficient changes of Al2O3-CNT composites as a function of CNT content in a wear test.

4. Summary The hardness and toughness were improved from or comparable with those of Al2O3 ceramics when the CNT additions are less than 10vol% in the composites. The hardness could be particularly enhanced by addition of 5vol% CNT in the composites. The wear resistance of Al2O3 can be improved by the addition of CNT when the CNT content is optimized. The wear loss decreased due to CNT addition up to 10vol%. The Al2O3-10vol% CNT composites sintered at 1500oC showed the lowest friction coefficient in this study. References [1] M. F. Yu, O. Lourie, M. J. Dyer, K. Moloni, T. F. Kelly and R. S. Ruoff, Science, 287 (2000) 637. [2] M. M. J. Treacy, T. W. Ebbesen and J. M. Gibson, Nature, 381 (1996) 678. [3] A. K. Kothari, S. Hu, Z. Xia, E. Konca and B. W. Sheldon, Acta Materialia, 60 (2012) 3333. [4] K.S. Lee, B.K.Jang and Y.Sakka J. Ceram.Soc.Jpn., 121 (2013) 867.

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Drift-Diffusion Simulation of MoS2 channel FETs Ferran Jovell, Xavier CartoixĂ 'HSDUWDPHQW GÂś(QJLQ\HULD (OHFWUzQLFD 8QLYHUVLWDW $XWzQRPD GH %DUFHORQD %HOODWHUUD 6SDLQ Ferran.Jovell@uab.cat Abstract Planar materials, such as graphene [1,2], have recently raised a great deal of interest due to the exceptional electronic properties, in particular a high electron mobility [3], which render them very attractive as the channel material for a field effect transistor (FET). On the other hand, graphene has a semimetallic character, with the bands crossing at the Fermi point, which causes a residual nonnegligible conductivity even in the off state. Thus, great efforts have been made in order to open a gap in graphene and render it a semiconductor. These include adding an extra dimension of confinement, obtaining graphene nanoribbons (GNRs) [4], electrostatic patterning [5], chemical decoration [6], etc., but that has been at a cost to the electronic transport properties [7]. A different approach is to choose a different planar material with a semiconductor character from the onset in order to fabricate an FET channel, such as Radisavljevic et al. have recently made [7] using MoS2, with an experimental direct gap of 1.8 eV [8]. The first experimental devices [7] have channels long enough that they are expected to operate in the drift-diffusion regime. From this point of view, drift-diffusion simulation of a 2D-FET can provide insight on technological parameters, such as the trap density inside the oxide, the quality of the interfaces, the presence of interface charges, the onset of short channel effects, etc. We have carried out these simulations, obtaining good agreement with the measurements of Radisavljevic et al. [7]. From these simulations we obtain that the electron affinity in MoS2 is about 5.25 eV (ca. 1 eV higher than the experimental value in [9]). Also, in order to reproduce the highly negative 12 -2 threshold voltage, a channel/HfO2 interface charge of +8Ă&#x2014;10 qe/cm must be included, pointing to a highly defective interface. We acknowledge financial support by the Spanish Ministerio de EconomĂa y Competitividad under Project No. TEC2012-31330. Also, the research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreement No. 604391 Graphene Flagship.

References [1] A. K. Geim and K. S. Novoselov. Nature Materials 6 (2007) 183. [2] K. S. Novoselov et al., Science 306 (2004) 666. [3] K. I. Bolotkin et al., Solid State Commun. 146 (2008) 351. [4] L. Brey and H. A. Fertig, Phys. Rev. B (2006) 73:235411 [5] Jeroen B. Oostinga, Hubert B. Heersche, Xinglan Liu, Alberto F. Morpurgo & Lieven M. K. Vandersypen, Nature Materials (2007) 7:151 Âą 157 [6] Xiaochen Dong, Yumeng Shi, Yang Zhao, Dongmeng Chen, Jun Ye, Yugui Yao, Fang Gao, Zhenhua Ni, Ting Yu, Zexiang Shen, Yinxi Huang, Peng Chen, and Lain-Jong Li, Phys. Rev. Lett. (2009) 102:135501 [7] B. Radisavljevic at al., Nature Nanotechnology 6 (2011) 147. [8] K. F. Mak et al., Phys. Rev. Lett. 105 (2010) 136805. [9] Min Sup Choi et al., Nature Comm. 4 (2013) 1624.

Figures

Fig. 1: The simulated MoS2FET transistor diagram. The channel is so narrow that cannot be appreciated in the diagram.

Fig. 2: Experimental [7] and simulated Ids vs. Vg curves, showing good agreement.

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Fully analytic spaser model: Understanding threshold limitations 1

1,2

Günter Kewes , Rogelio Rodriguez-Oliveros , Kathrin Höfer , Alexander Kuhlicke , Kurt Busch, and 1 Oliver Benson 1 Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany 2 Max-Born Institut, Max-Born-Straße 2A, 12489 Berlin, Germany gkewes@physik.hu-berlin.de We present a completely analytic model to describe spherical core-shell surface plasmon lasers (spasers). Our model drops the widely used quasistatic semi-quantum mechanical description in favour of fully vectorial Mie theory. This allows for precise incorporation of realistic gain relaxation rates that have been massively underestimated so far. Only this enables understanding of limiting dynamics that hinder efficient spaser devices up to now. Our model clearly demonstrates the dramatic beneficial impact of emitter-free spacing layers between gain and metal on the spaser threshold.

Self-Assembled Dendron-Cyclodextrin Nanotubes for Biosensory Platform Chulhee Kim, Jeonghun Lee Polymer Science and Engineering, Inha University, Incheon, Korea chk@inha.ac.kr

Abstract Nanotubes have been a subject of great interests due to their innovative properties and potential applications in a variety of areas of nanoscience. In particular, for organic nanotubes, the precise functionalization and interconnection of the building blocks provided a vision that they could exhibit not only unprecedented architectures but also valuable functions for applications such as electronics and biomedicine. Even though various self-assembling building blocks for nanotubes have been developed, a molecular recognition motif has not been employed for controlling the self-organization of building blocks into organic nanotubes. Recently, we have reported that the cyclodextrin (CD)-covered dendron nanotubes (Den-CD-NTs) were obtained by a hierarchical self-assembly process derived from a host-guest complexation between the amide dendrons with the focal pyrene moiety and cyclodextrins.[1,2] The smaller rim of CD is exposed to the surface of the nanotube upon inclusion of the focal pyrene groups into the cavity of CD. We reasoned that this type of hierarchical self-assembly approach would provide a facile methodology for the construction of diverse nanotube architectures via the host-guest interaction between the dendron and the C-6 modified CDs. The tunability in the surface functionalization would enable us to construct the hybrid of the nanotubes with metal nanoparticles. Furthermore, we also reasoned that the fluorescence characteristics of the nanotube in response to the change of the surface environment for the application of the nanotube as a biosensory vehicle. In the primary building block, amide dendron, the focal pyrene group was introduced not only as the guest moiety for a CD host but also as a fluorescent probe. Dendron selforganizes into vesicles in aqueous solution. Upon addition of CDs into the vesicular solution, the CDpyrene complexation occurs through the inclusion of the hydrophobic focal pyrene unit into the cavity of CD. This supramolecular recognition transforms the self-assembled structures from the vesicle to the CD-covered nanotubes. The fluorescent nature of Den-CD-NTs with the tunable surface functionality described in this work provides an opportunity for utilizing the nanotubes as a biosensing platform when the surface functional groups of the nanotubes are designed to interact specifically with the analytes. The sensitive emission property of the pyrene unit in the cavity of CDs of the nanotube toward the change in local environment would allow such binding of the biomolecules on the nanotube to trigger the change in the fluorescence emission of the nanotubes. For that purpose, we prepared the biotin-covered nanotubes (Den-biotin-CD-NT and Den-biotin-C4-CD-NT) as a biosensing platform for utilizing the specific binding of biotin with receptor proteins such as streptavidin and avidin. When streptavidin-AuNP conjugate (SA-AuNP) was added to the Den-biotinC4-CD-NT solution, the fluorescence was quenched due to proximity of the pyrene moiety to the AuNP of SA-AuNP which binds to the biotin unit on the tube surface. These fluorescence characteristics of Den-CD-NTs along with well-defined surface architecture suggest that Den-CD-NTs can be utilized as a biosensor. The functional tunability of Den-CD-NTs demonstrated the substantial advantages of our supramolecular approach for development of unique nanotubes as a sensory vehicle.

References [1] J. Lee, C. R. Lohani, K.-H. Lee, C. Kim, New J. Chem., 2013, 37 (11), 3598.

[2] J. Lee, S. Park, C. R. Lohani, K.-H. Lee, C. Kim, Chem. Eur. J., 2012, 18 (24), 7351. [3] C. Park, J. Lee, C. Kim , Chem. Commun., 2011, 47 (44), 12042. [4] C. Park, M. S. Im, S. Lee, J. Lim, C. Kim, Angew. Chem.Int. Ed. 2008, 47 (51), 9922. [5] C. Park, I. H. Lee, S. Lee, Y. Song, M. Rhue, C. Kim, Proc. Natl. Acad. Sci. U. S. A., 2006, 103, 1199.

Mechanism of Low-voltage Field Emission from Carbon Nanotube Cathode G.G. Kosakovskii1 , Z.Ya Kosakovskaya1, E.V. Blagov2, Yu.I. Latyshev1, A.P. Orlov1, A.M. Smolovich1. 1 .RWHOÂśQLNRY ,QVWLWXWH RI 5DGLR (QJLQHHULQJ DQG (OHFWURQLFV RI 5$6 0RNKRYD\D 1, 2Institute

Moscow, Russia of Nanotechnology Microelectronics of the RAS, Nagatinskaya 16, Moscow, Russia German_kos@mail.ru

Already first study of a field emission from carbon nanotube (CNT) were shown the abnormally high density of emission current (up to 2-3 orders) at a low magnitude of electric field intensity [1]. It is known the similar deviation from Fowler-Nordgeim function (FN) have also the flat cathodes, which were coated by films with the low-dimensional structures such as Ge-Si, In-Sn-O and diamond-like films [2, 3]. The object of our work was study the peculiarities of low-voltage field emission (LVFE) from CNT emitter at condition of the dimensional quantization of charge. For measuring of the current-voltage characteristics the model of nanodiode was assembled in SEM Carl Zeiss 40 (Fig.1 a). As emitters were used the direct nanotubes with diameter of 14 nm and length of 1.4 microns which was synthesized by arc method. The study of the nanotube field emission were conducted in two modes: (i) into electrostatic field by scan of current-voltage characteristics with a voltage step 30 mV; (ii) into microwave field by the scan of frequency. The following results were obtained at the study of field emission of nanodiode with CNT emitter. Measured value of the emission current is always more the value current calculating by FowlerNordheim equation. On F-N plot of CVC curve, we can see the resonance peaks (fig.1b) and the voltage threshold for start emission (Uthr) (fig.1c). Emergence of a resonance peaks on the CVC curve near the Van Hove singularities indicates the existence of conduction channels which caused by the size quantization in the nanotube emitter. At U < Uthr the conductivity of electric circuit of CNT emitter decreases with increasing voltage. At U < Uthr the conductivity decreases with increasing voltage. When U > Uthr observed the field electron emission which is always accompanied by IR emission. Resonance peaks on CVC curve correspond to the conduction channels, which always have the negative sections differential conductivity (Fig.2). Study of the charge density distribution along the nanotube axis revealed the appearance of the superlattice into electron gas near the voltage threshold. It was established that the superlattice period decreases with increasing voltage between the anode and the cathode. (Fig.3a -b). The interaction between the electronic systems of individual non-contacting nanotubes was found which could be explained by the collectivization of their electronic states. By summarizing results, we may make following conclusion. The resonance peaks of I-V characteristic indicate the quantum nature of the of the charge transport in circuit nanotube emitter. Superlattice of electronic gas and the dependence of its period from applied voltage, and the interaction of the electronic subsystems of individual CNTs (Fig. 3), the negative differential conductance indicate on the collective nature of the charge transport near the Van Hove singularities. There are the potential barriers on both ends of the nanotube emitter, which cause the localization of charge carriers into nanotube (Fig. 4). Ballistic the nanotube conductivity of nanotubes and the potential barriers at both ends thereof are the cause of size quantization electron along the nanotube length nanotube emitter. It is for this reason, increasing the applied voltage (V < V thr) causes a decrease of CNTs conductivity and the simultaneous increases of charge density (Fig. 1). When the Fermi level approaching to the Van Hove point the charge density is growing rapidly and the conditions for the condensation of the Fermi electron gas to a Luttinger liquid are appearing. As a result of the Friedel oscillations on the potential barriers are emerged the standing wave of charge density of a localized electrons which formed superlattice along nanotube. At the same time the energy of the potential barriers at both ends of the nanotube have redistributed by the Friedel oscillations. Potential barrier height drops dramatically and the process of collective tunneling of electrons through potential barrier to vacuum collective electron tunneling process through potential barrier to vacuum begins at low voltage. Note that in the emitter circuit together with a DC emission current flows AC current whose frequency depends on the voltage applied. References [1] Chernozatonskii L.A., Gulayev Yu.V., Kosakovskaya Z.Ya et al., Chem.Phys.Lett., 233, (1995) 63 > @ 6HRN :RR /HH 6HXQJ 6 /HHÄ (XL-Hyeok Yang. Nanoscale Res Lett, 4, (2009) 1218

[3] Chang Hwa Lee, Seok Woo Lee, Seung S. Lee. Nanoscale Res Lett., 5, (2010) 1128 Figures

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Safety and internalization effectiveness of magnetic iron oxide nanoparticles 1,2

1,2

2,3

Ana Lazaro-Carrillo , Macarena Calero , Lucía Gutiérrez , Gorka Salas , Yurena Luengo , Pilar 1 3 2,4 1,2 Acedo , M. del Puerto Morales , Rodolfo Miranda , Angeles Villanueva 1

Departamento de Biología, Universidad Autónoma Madrid, Darwin 2, Madrid, Spain IMDEA-Nanociencia, Ciudad Universitaria de Cantoblanco, Faraday 9, Madrid, Spain 3 ICMM-CSIC, Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid, Spain 4 Departamento de Física de la Materia Condensada, Universidad Autónoma Madrid, Francisco Tomás y Valiente 7, Cantoblanco, Madrid, Spain ana.lazaro@uam.es 2

Recent advances in nanoscience and nanotechnology have led to the development of nanomaterials for medical applications. Magnetic nanoparticles (MNPs) are attracting widespread attention because of their applications in biomedicine, in particular with the diagnostic and therapeutic purposes. However, a critical issue in nanomaterials is the clear understanding of their potential toxicity. Physical and chemical characteristics of nanoparticles (such as size, chemical composition, crystalline structure and surface properties) are proposed to determine critically their toxic potential as well as their specific accumulation in tumor cells. In this sense, quantitative study of nanoparticle uptake at the cellular level is critical for nanomedicine applications as first step to evaluate their biocompatibility before in vivo analysis. Hence, any new magnetic nanoparticle (MNPs) formulation with potential biomedical applications should be accompanied by a detailed study that ensures both its entry effectiveness and safety. In this sense, several specific parameters and experimental protocols for assessing nanomaterial toxicity have been developed. In this study we present a deep analysis on biocompatibility and intracellular accumulation of iron oxide nanoparticles with three different coatings: aminodextran (AD), 3-aminopropyl-triethoxysilane (APS), and dimercaptosuccinic acid (DMSA), which result in different particle charge, in HeLa (human cervical adenocarcinoma) cells. This cell line is commonly used for cytotoxicity evaluation in different research fields, including nanomaterials, and therefore it provides a good basis for comparison. Iron oxide nanoparticles were used because of its low toxicity and the existence of natural routes for its degradation. MNPs were obtained by different synthetic routes, including coprecipitation and decomposition in organic media. Uniform nanoparticles in size and shape were observed by transmission electron microscopy. Colloidal characterization was performed by dynamic light scattering (DLS) showing hydrodynamic size below 150 nm (which assure good properties) and a Z-potential ranging from highly positive for APS coated MNPs to moderate positive and highly negative for AD and DMSA coated particles respectively (Figure 1). Uptake of MNPs as well as their accumulation inside HeLa cells after prolonged incubation (up to 72 h), were assessed by light and scanning electron microscopy methods and quantification of intracellular iron content by ferrozine assay, thus allowing to correlate the overall cell visualization and their subcellular location with the precise amount of MNPs inside cells. These nanoparticles show excellent properties for possible in vivo biomedical applications such as cell tracking by magnetic resonance imaging (MRI) and cancer treatment by hyperthermia or drug delivery: (i) they enter into cells with effectiveness (higher in APS coated MNPs than in DMSA or AD MNPs) (see Figures 2 and 3 ) and are localized in endosomes; (ii) they can be detected inside cells by optical microscopy, (iii) they are retained for relatively long periods of time, and (iv) they do not induce any cytotoxicity, which was assessed by cell morphology observation, study of cytoskeleton and adhesion proteins, analysis of cell cycle, presence of intracellular ROS (reactive oxygen species), MTT(methyl thiazol tetrazolium bromide) assay and Trypan blue exclusion test [1]. * This work was partially supported by grants from EU-FP7 (no 262943) and Spanish Ministry of Economy and Competitiveness (CTQ2010-20870C03-03 and MAT2011-23641) and Madrid regional government CM (S009/MAT-1726).

References [1] M. Calero, L. Gutiérrez, G. Salas, Y. Luengo, A. Lázaro, P. Acedo, MP. Morales, R. Miranda, A. Villanueva. Nanomedicine (2014) 10, 733-43.

Figures

DMSA

APS

Figure 1. (A) TEM images of AD, DMSA and APS-coated magnetic nanoparticles. (B) Surface charge variation as a function of pH for MNPs. (C) Hydrodynamic size for magnetic nanoparticles.

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b DMSA

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Figure 3. (A) Cell cycle of control and cells incubated with MNPs. (B) Qualitative characterization of ROS generation by DCFH-DA assay. (C) SEM pictures of HeLa cells. (a) Control cell. (b-d) Cells incubated for 3 h with 0.1 mg ml -1 AD, DMSA and APS, respectively. Scale bar = 10 µm. (D) No significant differences on cell survival, in comparison with controls, were observed 24 h after incubation with MNPs by MTT or Trypan blue assay.

Electronic structure of stripped graphene nanoribbons delimited by sp3 defect lines: A density functional theory study J. X. Lian, Y. Olivier, D. Beljonne Laboratory for Chemistry of Novel Materials, University of Mons, 20 place du parc, Mons, Belgium E-mail: jian.lian@umons.ac.be Abstract Graphene has been touted as the miracle material because of both its exceptional mechanical and electronic properties. However, owing to its semimetallic properties (absence of a band gap) its applications in electronic remain limited. Graphene nanoribbons (GNRs) appears as a particularly interesting alternative. Indeed, the electronic structure of GNRs can be tuned from a metallic to a 1-4 To provide semiconductor behavior through a tailored quantum confinement and edge effects. semiconducting properties to graphene with sufficiently large gaps, sub-5nm GNRs are required in order 1-3 to reach graphene-based FETs with proper on/off ratio at room temperature. 2 3 The formation of covalent bonds transforms the sp carbons of graphene to sp , opening a band gap 5 and generating semiconducting regions. This approach has been successfully applied for other carbon 6,7 nanostructures such as fullerenes and carbon nanotubes. In this work, we perform Density Functional Theory (DFT) calculations of the geometric and electronic structures of stripped graphene delineated by chemical defects. We show that the bonding of hydrogen atoms on specific carbon atoms along the armchair direction effectively breaks the ʌ-delocalization and opens a band gap. The density and the positions of such defects at the surface of graphene have been varied while simultaneously probing the influence on the electronic structure of the resulting periodical disruption in ʌ-conjugation. References [1] Raza, H., & Kan, E. C., Phys. Rev. B 77, 245434 (2008). [2] Son, Y. W., Cohen, M. L., & Louie, S. G., Phys. Rev. Lett. 97, 216803 (2006). [3] Han, M. Y., Ozyilmaz, B., Zhang, Y. & Kim, P., Phys. Rev. Lett. 98, 206805 (2007). [4] Li, X. L., Wang, X. R., Zhang, L., Lee, S. & Dai, H. J. Science 319, 1229±1232 (2008). [5] M. Quintana, et al., Phys. Stat. Sol. B 247, 2645 (2010) [6] M. Maggini, G. Scorrano, M. Prato, J. Am. Chem. Soc. 115, 9798 (1993) [7] P. Singh, M. Prato, et al., Chem. Soc. Rev. 38, 2214 (2009)

Acknowledgements This work is done in the frame of the project UPGRADE, which acknowledges the financial support of the Future and Emerging Technologies (FET) programme within the Seventh Framework Programme for Research of the European Commission, under FET-Open grant number: 309056

High bright Ag-carbon dots-silica hybrid mesoporous nanosphere Chunyan Liu, Zhiying Zhangˈ Yun Liu Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China cyliu@mail.ipc.ac.cn

Abstract Ag-enhanced fluorescent carbon dots-silica hybrid mesoporous spheres (Ag-CDSiMs) with a large surface area (>300m2/g) have been prepared through a facile method with silane-functionalized carbon dots (Si-CDs) [1, 2]. Comparing with fluorescent dyes, II-VI and III-V semiconductor quantum dots, carbon-related quantum dots (CQDs) have exhibited well chemical and photo-stability, non-toxicity and non-blinking nature [3-5]. Herein, we used environmentally-friendly silane functionalized CDs as luminescent species to fabricate metal enhanced luminescent mesoporous silica. It is worth noting that through the asinvented one- step method, the formation of metal NPs and mesoporous structured silica, and the immobilization of luminescent CQDs is finished simultaneously. For the decoration of silver Nanoparticles, the fluorescent intensity of CDs hybrid mesoporous silica enhanced nearly 3.5-times. With the help of the covalent link of CDs and mesoporous silica host, the fluorescent species was effectively anchored into mesoporous nanosphere, even in an organic solvent or very acidic medium. This work provides a new strategy and thinking for the fabrication of super bright mesoporous silica, as well as the interaction of metal and luminescent species.

References [1]. Wang F., Xie Z., Zhang H., Liu Chun-yan; Zhang Y., Adv. Funct. Mater., 21 ˄2011˅1027-1031. [2]. Wang Fu, Xie Zheng, Liu Yun, Yang Wen-dong, Liu Chun-yan, Nanoscale, 6˄2014˅3818-3823. [3]. Zhang Z., Zhang J., Chen N., Qu L., Energy Environ. Sci., 5 ˄2012˅8869–8890. [4]. Sun Y. P., Zhou B., Lin Y., Wang W., Fernando K. A. S., Pathak P., J. Am. Chem. Soc. 128 ˄ 2006˅ 7756-7757. [5]. Tian L., Ghosh D., Chen W., Pradhan S., Chang X., Chen S., Chem. Mater. 21˄2009˅2803-2809.

Optical spectra and quasiparticle energies of molecules using a local basis Mathias P. Ljungberg, Peter Koval, Francesco Ferrari, Dietrich Foerster, Daniel Sanchez-Portal DIPC, San Sebastian, Spain mathias.ljungberg@gmail.com Abstract The Bethe-Salpeter equation (BSE) is the state of the art for computing optical spectra for solids and molecular clusters. Here we present an implementation of BSE for clusters that scales asymptotically like O(N^3) with the number of atoms, achieved by exploiting the locality of the problem in the local basis set representation and by using the Haydock recursion method to compute the spectrum. Using a pseudhermitian Lanczos algorithm we can go beyond the Tamm-Dancoff approximation within our iterative scheme. As a starting point for the BSE we compute quasiparticle energies with our low-scaling GW implementation [1], retaining the frequency dependence of all quantities and thus avoiding the plasmon-pole model or similar schemes. The initial wave functions are taken from a preceding SIESTA calculation. We discuss the influence of self-consistency on the quasiparticle energies [2] and its effect on the BSE spectra. We also investigate the satellite peaks that are present in the GW density of states. Computed GW/BSE spectra are shown for some organic molecules of medium size that are relevant for photovoltaic applications.

References [1] D. Foerster et al. J. Chem. Phys. 135 (2011) 074105 [2] P. Koval et al. Phys. Rev. B 89 (2014) 155417 Figures Optical spectrum for benzene BSE@G0W0 (ev self-consistent) experimental arb. units

arb. units

BSE@G0W0(ev oneshot) experimental

9 10 11 12 13 14 15 16 17 18

t (eV)

t (eV) TDDFT experimental arb. units

BSE@qsGW (self-consistent, modeA) experimental arb. units

9 10 11 12 13 14 15 16 17 18

9 10 11 12 13 14 15 16 17 18 t (eV)

Temperature-controlled growth of single-crystal Pt nanowire arrays for high performance catalyst electrodes in polymer electrolyte fuel cells Yaxiang Lu, Shangfeng Du, Robert Steinberger-Wilckens School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK yxl210@bham.ac.uk Abstract In the past decades, studies have been intensively conducted for the development of high performance electrocatalysts with novel nanostructures. Previous results have established that the electrocatalytic activity and durability of electrocatalysts not only depended on the ratio of surface area to volume, but also arrangements of atoms, the surface structures and their morphologies. For example, the high surface energy of extremely small nanoparticles often induces severe aggregation and Ostwald ripening, which are considered as two of the main contributors to the fast drop of power output and significant degradation of cycling life. Compared with zero-dimensional (0D) nanoparticles, one-dimensional (1D) Pt nanostructures such as nanowires, benefiting from the inherent structural characteristics like anisotropy and preferential exposure of highly active crystal facets, exhibit enhanced catalytic activity and durability [1]. For example, Lee et al. [2] synthesized single-crystal Pt nanowires (PtNWs) on Pt and W gauzes, which showed excellent catalytic activities towards oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). Liang et al. [3] prepared a free-standing Pt nanowire membrane and demonstrated that the 1D nanostructure displayed remarkably higher catalytic stability than Pt/C and Pt black. In the synthesis of nanostructures, reaction temperature has been regarded as an important controlled factor. Controlling temperature is a good tool to tune the phase formation kinetics and the driving force for mass transfer, thus changing the morphology and property of the product. Unfortunately, up to today, most studies related to Pt nanowires only focused on a fixed temperature, because it has been usually agreed that a relative low reaction temperature is necessary to slow down the reduction rate of Pt ions, favouring the growth of {111} planes and therefore leading to the formation of single-crystal Pt nanowires. For instance, at room temperature, Sun et al. [4] synthesized single-crystal Pt nanowires on carbon black via the reduction of H2PtCl6 by HCOOH. At 110 掳C, Xia et al. [5] grew Pt nanowires by reducing H2PtCl6 with ethylene glycol in the presence of polyvinyl pyrrolidone (PVP). However, in the synthesis of nanostructures, the growth temperature also plays a key role on their behavior, e.g. distribution and aggregation of nanostructures. In practical applications, the behavior of Pt nanowires is as important as the Pt nanowires themselves. For example, when Pt nanowires are used as electrocatalysts in fuel cells, they should possess an optimal distribution in the catalyst layer to achieve a low charge and mass transfer resistance, a suitable length to enable self-support, and an ultra-thin size to obtain a high electrochemical surface area. This highlights the importance of a finely tuned synthesis temperature for simultaneously controlling the behavior and structure of Pt nanowires for practical applications. To further understand the influence mechanism of the growth temperature on the behavior and structure of Pt nanowires, in this work, we study Pt nanowire (Pt NW) growth at various temperatures at 5, 15, 25, o 35, 40 and 50 C. Hexachloroplatinic acid hexahydrate (H2PtCl6路6H2O) is used as Pt precursor with 2 formic acid as the reducing agent and a large-area 16 cm carbon paper (Sigracet 35 BC GDL) as support. The as-prepared carbon paper pieces with in-situ grown Pt nanowires are directly tested as gas diffusion electrodes (GDEs) at the cathode side in H 2/air polymer electrolyte fuel cells (PEFCs). The morphology and distribution of Pt nanowires in GDEs are analyzed with a field emission scanning electron microscope (FE-SEM). The experiment results indicate that the growth temperature plays a key role in this process. At the low temperature, the main structures obtained are huge PtNW aggregates at the corner area of the GDE piece (Fig. 1a), but very sparse at the center area (Fig. 1b), resulting in a low catalyst utilization and poor catalytic performance. An increased temperature leads to an improved distribution of Pt NWs on o the support surface, e.g. at 25 C, more Pt nanowires are grown in the center area (Fig. 1c). However, too high the reaction temperature results in the formation of nanoparticles in solution. When the o temperature reaches 50 C, it can be seen that a lot of small nanoparticles are formed and pile up on the o surface (Fig. 1d). An optimal temperature is achieved at 40 C, where uniform Pt nanowire arrays grow RQ WKH VXSSRUW VXUIDFH, covering evenly the whole area. They have a length of 10-20 nm and a diameter 1

of 4 nm in average. The fuel cell testing results further confirm WKH EHVW FDWDO\WLF SHUIRUPDQFH of the o -2 GDE grown at 40 C (Fig. 2). A maximum power density of 0.82 W cm was obtained at 0.6 V, higher than the state-of-the-art commercial TKK Pt/C catalyst. Considering the power performance in practical fuel cells and the PtNW behaviour on the support surface, a possible mechanism for the influence of temperature on PtNW growth is suggested. Our improved understanding here from PtNW GDEs could provide useful reference for research on novel nanostructures in fuel cells and other catalytical applications. References [1] S. Du, Int. J. Low-Carbon Technol., 7 (2012) 44-54. [2] E.P. Lee, Z.M. Peng, D.M. Cate, H. Yang, C.T. Campbell, Y.N. Xia, J. Am. Chem. Soc., 129 (2007) 10634-10635. [3] H.W. Liang, X.A. Cao, F. Zhou, C.H. Cui, W.J. Zhang, S.H. Yu, Adv. Mater., 23 (2011) 1467-1471. [4] S.H. Sun, F. Jaouen, J.P. Dodelet, Adv. Mater., 20 (2008) 3900-3904. [5] J.Y. Chen, T. Herricks, M. Geissler, Y.N. Xia, J. Am. Chem. Soc., 126 (2004) 10854-10855. Figures

Fig. 1. SEM images of PtNW GDEs grown at (a-b) 5, (c) 25, (d) 50 and (e) 40 C. a) shows the corner, 2 b-e) show the center area of a 16 cm PtNW GDE.

Fig. 2. Polarization and power density curves of PtNW GDEs grown at different temperatures and the o -1 one with TKK Pt/C catalyst. The polarization curves are recorded at 70 C at a scan rate of 1 mV s . H2 o and air gases are humidified at 75 C with the stoichiometry of 1.3/2.4, respectively. The backpressure is 2 bars at both sides.

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Ionic liquids and deep eutectic solvents in the preparation of nanostructures Roksana Markiewicz, Stefan Jurga NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 60614 Poznan, Poland roksana.markiewicz@amu.edu.pl

Abstract Nanostructures due to their small size, in comparison with their bulk counterparts, possess unique properties including magnetic, electrochemical and photonic properties. Therefore, such nanomaterials found a wide variety of application in different fields such as catalysis, electronic and spintronics, life and material sciences. Controlling the morphology and structure of nanomaterials is of considerable interest, since it leads to materials with chosen physicochemical properties and functions. Various methods of preparation of thereof were described, and the use of ionic liquids and deep eutectic solvents is particularly interesting. Ionic liquids (ILs) are salts composed of an organic cation and organic or inorganic anion, which have attracted much attention as media for the preparation of metal, metal oxides and organic nanostructures, due to their unique properties like negligible vapor pressure, wide liquid range, electrochemical and thermal stability and very good dissolving ability. The low surface tension of many ILs leads to high nucleation rates and small size of prepared structures, and as highly structured fluids, have a strong effect on the morphology od particles formed, therefore they are often called shape directing solvents [1]. With the great number of combinations of the anion-cation possible, it is possible to design an ionic liquid with task specifity. ILs form solvation layers around the nanomaterials thereby excluding the need for addition of any external stabilizing and capping agents [2] To overcome the difficulties that ILs may bring (high price, toxicity, availability), a new generation of solvents called Deep Eutectic Solvents (DES), have been described. Formation of such DES can be obtained by simply mixing together two cheap and safe components capable of forming an eutectic mixture. DES may be used as a replacement of the traditional surfactants and growth promoter of various nanoparticles. They also play a role of stabilizer of metal and metal oxides nanoparticles.[3] The aim of this work is to present the ionic liquids and deep eutectic solvents as a media for nanostructures preparation. This work was supported by the European Grant No. POKL.04.01.01-00-049/13. References [1] J. Dupont, Accounts of Chemical Research, 44(11) (2011) 1223-1231. [2] A. B. Patil, B. M. Bhanage, Physical Chemistry Chemical Physics 16(7) (2014) 3027-3035. [3] Q. Zhang, K. De OliYHLUD 9LJLHU 6 5R\HU ) -pU{PH &KHPLFDO 6RFLHW\ 5HYLHZV 41(21) (2012) 7108-7146.

The effect of photon energy on hot-carrier mediated photoresponse in graphene M. Massicotte, K.J. Tielrooij and F.H.L. Koppens ICFO - Institut de CiĂŠncies FotonĂques, Mediterranean Technology Park, Castelldefels (Barcelona) 08860, Spain mathieu.massicotte@icfo.es Graphene is a promising material for optoelectronic applications requiring efficient and fast light-tocurrent conversion. Over the last years, its intrinsic photoresponse has been the subject of intensive studies, which generally suggest that the photo-thermoelectric effect can play an important role in the generation of photoresponse [1]. This mechanism relies on the heating of carriers near a junction between regions with different Seebeck coefficients. These hot carriers are generated directly after electron-hole pair excitation by photons and subsequent energy relaxation through carrier-carrier scattering [2]. Here, we address the role of the photon energy on the photo-response driven by hot carriers. We perform the first comprehensive study of the role of the photon energy on the photoresponse for various graphene photodetectors. In order to unravel the effect of photon energy on the graphene photo-thermoelectric photoresponse, we use a photodetector fabricated on a transparent substrate such that interference effects [3] are inhibited. We find that the power-normalized photocurrent as a function of wavelength is constant, which corresponds to a quantum efficiency that scales linearly with photon energy. Thus a photon with higher energy generates a larger photocurrent, in agreement with efficient carrier heating in graphene [2]. References [1] Gabor N. M., et al. Science, 334, 6056 (2011) [2] Tielrooij K. J., et al. Nature Physics, 2564 (2013) [3] Blake P., et al. Applied Physics Letters, 91(2007)

Infrared Resonant Antenna Tips for Enhanced Near-Field Mapping of Molecular Absorption Florian Huth1,2, Andrey Chuvilin1,3, Martin Schnell1, Iban Amenabar1, Roman Krutokhvostov1, Stefan Mastel1 and Rainer Hillenbrand1,3 1

CIC nanoGUNE Consolider, 20018 Donostia-San Sebastian, Spain 2 Neaspec GmbH, 82152 Martinsried, Germany 3 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain s.mastel@nanogune.eu

We report the development of infrared-resonant antenna probes for tip-enhanced optical microscopy [1]. We employ focused-ion-beam (FIB) machining to fabricate high aspect ratio gold cones, which replace the standard tip of a commercial Si based AFM cantilever (Fig. 1a). Calculations show large field enhancements at the tip apex due to geometrical antenna resonances in the cones, which can be precisely tuned throughout a broad spectral range from visible to THz frequencies by adjusting the cone length. Spectroscopic analysis of these probes by FTIR and nano-FTIR [2] corroborates their functionality as resonant antennas and verifies the broad tunability (Fig. 1b). By employing the novel probes in a scattering-type near-field microscope and imaging a single tobacco mosaic virus (TMV), we experimentally demonstrate high performance mid-infrared nano-imaging of molecular absorption (Fig. 1c). Our probes offer excellent perspectives for unprecedented optical nano-imaging and nanospectroscopy, pushing the detection and resolution limits in many applications, including nanoscale infrared mapping of organic, molecular, and biological materials, nano-composites, or nano-devices [34]. Furthermore, due to their well-defined geometry the antenna probes will significantly ease the qualitative description of the tip-sample near-field interaction, which will be essential for quantitative measurements of the local sample properties such as dielectric function and molecular absorption. References

[1] F. Huth et al., Nano Lett. 13, 1065 (2013) [2] F. Huth et al., Nature Materials 10, 352 (2011) [3] J. Stiegler et al., Nature Comm. 3, 1131 (2012) [4] A. Huber et al., Nature Nanotech. 4, 153 (2009) (b) s2

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Structural and electronic properties of bimetallic AunAgm, (n + m = 20, n:m = 1:0, 3:1, 1:1, 0:1) clusters and their ions: a relativistic DFT study

Bertha Molina , Alonso E. Viladomat , Jorge R. Soto , and Jorge J. Castro

Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Apdo. Postal 70-646, 04510, México, D.F., México. 2 Departamento de Física, CINVESTAV del IPN, Apdo. Postal 14-740, 07000, México, D.F., México. Abstract In recent years, the study of the Au-Ag bimetallic nanoparticles has attracted considerable attention due to the possibility of tuning their optical and electronic properties as a function of the gold and silver proportions. In general, from a theoretical point of view, the search for the lowest energy bimetallic structures presents a challenging problem due to the large number of skeletal geometric structures and homotopic distributions to be considered. Furthermore, the analysis of the Au-Ag system introduces the additional component of the relativistic effects, present in the gold atom, that have to be considered. In this work, using the relativistic approach ZORA-DFT, we report the local minima in the potential energy surface of bimetallic Au nAgm, (n + m = 20) clusters and their ions in selected proportions (n:m=1:0, 3:1, 1:1, 0:1) in the gas-phase. We also discussed their respective electronic properties and possible aggregation or segregation structural motifs. The authors acknowledge to the GENERAL COORDINATION OF INFORMATION AND COMMUNICATIONS TECHNOLOGIES (CGSTIC) at CINVESTAV for providing HPC resources on the Hybrid Cluster Supercomputer "Xiuhcoatl" and the DIRECCIÓN GENERAL DE CÓMPUTO Y DE TECNOLOGÍAS DE LA INFORMACIÓN (DGTIC-UNAM, SC14-1-I-50 project). B. Molina acknowledges support by PAPIIT-DGAPA, UNAM IN119811.

Investigation of metal oxides deposition on electrical properties of CVD Graphene S. Mzali1, O. Bezencenet1*, J-P Mazellier1, B. Dlublak2, M-B Martin2, B. Servet1, S. Xavier1, A. Centeno3, S. Bansropun1, P. Seneor2, P. Legagneux1 1

Thales Research and Technology, 91767 Palaiseau, France Unité Mixte de Physique CNRS/Thales, 91767 Palaiseau, France, and University of Paris-Sud, 91405 Orsay, France 3 Graphenea SA, 20018 Donostia-San Sebastián, Spain 2

*odile.bezencenet@thalesgroup.com Abstract During the last decade, graphene has gained increasing attention and research interest due to its outstanding properties that make it an excellent candidate for advanced applications in future electronics and photonics [1]. In particular, the potential of graphene for optoelectronic applications is currently being explored extensively because of its high carrier mobility and absorption from the far infrared to the ultraviolet [2]. Nevertheless the fabrication of graphene-based devices is still challenging: the impact of the fabrication process on device performance is now well accepted, but is yet to be fully detailed. Here we report on the evaluation of growth of metal oxides (Al2O3 and HfO2) on electrical properties of graphene-based structures. Complementary techniques have been used to characterize graphene before and after metal oxide growth: MicroRaman spectroscopy to characterize the graphene quality and doping, Atomic Force Microscopy to determine the uniformity of the dielectric grown on CVD graphene. For this study; we address more specifically the influence of the metal oxide layer deposited as a protecting layer and/or as a passivation layer. The following samples have been fabricated: - with/without a protecting metal oxide layer, deposited by evaporation after graphene transfer. - with/ without a passivation layer, deposited by evaporation or atomic layer deposition[3,4] at the end of the process Comparisons of the electrical properties carried out on each sample highlight the benefits of a protective layer as well as a passivation layer. Metal oxide layers deposited by atomic layer deposition have shown interesting results in term of stable and reproducible Dirac point close to 0V (Figure 1). This work was funded through the European projects Grafol and Flagship.

References [1] Novoselov K. S, et al. Nature 2012, 490, 192í [2] Bonaccorso F., et al. Nature Photon. 4, 611–622 (2010). [3] Dlubak B., et al. J. Appl. Phys. Lett. 100, 173113 (2012) [4] Weatherup R.S., et al.Nano Lett, 13, 4624-4631 (2013) Figures

Figure 1. Transfer of a passivated graphene field effect transistor measured under ambient conditions after 4 weeks storage and subsequent annealing.

Nanohybrid of Activated Carbon Nanotube-Porphyrin as a Recyclable Catalyst for Aqueous Oxidation of Hydrocarbons with n-Bu4NHSO5 ! A. !!"#$%& %#’ Jilla saffarib #($)#*+&

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Abstract Nano-sized functional hybrid materials have become a highly innovative research ﬁeld. The ability to tailor the organic part combined with the properties of the nanosized inorganic matrixes is of great interest for potential applications in electronics, optics and catalysis. In particular, an association of a metal complex with a catalytically active inorganic support could provide a catalyst having improved catalytic properties due to the combination of two di!erent catalytic sites in one material [1]. Carbon nanotubes (CNTs), as a new type of carbon material among the solid supports, are cylindrically shaped and have appropriate pore-size distributions favoring maximum metallic dispersion [2]. Their morphology and special and steady structural characteristics are quite suitable for their use as hybrid catalysts, consisting of a metal complex anchored on a solid support, which could be regarded as a novel system able to combine the advantages and to overcome the drawbacks of homogeneous and heterogeneous catalysis [3]. Especially, their surface properties can be modified through various treatments to satisfy special needs. They can represent a new class of advanced materials for catalytic applications because of specific metal support interactions given by their graphitic structure, which can improve the catalytic selectivity/activity as well as their specific surface area. CNTs exhibit extraordinary chemical, electrical, thermal and mechanical strength characteristics, allowing for several potential applications in biological materials catalysts. The development of clean oxidation processes is an important topic in current chemistry and industry. A new challenge is to make innovative, “clean” methods by using non-toxic solvents in particularly aqueous media. In this regard, the use of water as a reaction solvent has attracted great attention in the recent past and has become an active area of research in green chemistry. !

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! ! ! References [1] S. Iijima, T. Ichihashi, Nature 1993, 363, 603 – 605; b) S. Iijima, Nature 1991, 354, 56 – 58. [2] D. S. Bethune, C. H. Kiang, M. S. de Vries, G. Gorman, R. Savoy, J. Vazquez, R. Beyers, Nature1993, 363, 605 – 607. [3] a) R. H. Baughman, A. A. Zakhidov, W. A. de Heer, Science 2002, 297, 787 – 792;

Zinc oxide quantum dots as a candidate for memory devices Paula Obreja, Dana Cristea, Cristian Kusko, Raluca Gavrila, Iuliana Mihalache, Mihai Daniala, Adrian Dinescu National Research and Development Institute for Microtechnologies, 126A (32B) Erou Iancu Nicolae Street, R-077190, Voluntari, Ilfov, P.O. BOX 38-160, 023573 Bucharest, ROMANIA paula.obreja@imt.ro Abstract In the last ten years, zinc oxide quantum dots (ZnO QDs) have attracted considerable attention due to their wide applications such as ultraviolet light-emitting diodes, blue luminescent devices, UV lasers and bio-sensing devices. ZnO QDs were synthesized by several methods, such as RF magnetron sputtering, ion implantation, vapor phase transport process, metal-organic chemical-vapor deposition, spray pyrolysis and by wet chemical methods. These dots are the particle size smaller than 8 nm (typically 3-6 nm). The wet chemical methods are simple and less expensive, but the obtained ZnO QDs need to be stabilized to keep them dispersed in solution or capped with polymers, amines, organic thiols or oleic acids to limit the growth. This causes some drawbacks when ZnO QDs processed into thin films for applications in electronic devices. In this paper ZnO QDs have been synthesized by direct precipitation of zinc acetate dihydrate solution in methanol with potassium hydroxide in methanol, added drop by drop under constant and continuously magnetic stirring, at room temperature [1, 2]. At the beginning 1% aluminum chloride was added in the solution to enhance n-type conduction; propyltrimethoxysilane was added to the solution at the end to maintain dispersion, to prevent the aggregation of ZnO QDs and their further growth. ZnO QDs were separated from solution by centrifuging and removing of the supernatant, washed three times with methanol, re-dispersed in ethanol at different concentrations and used for the investigation of ZnO QDs characteristics. Also, the solutions were used for spin coating of the thin film on different substrates (quartz, SiO2/Si and SiO2/Si substrates with pre-patterned Cr/Au electrodes for electrical characterization). ZnO QDs size was evaluated using atomic force and scanning electron microscopy. The morphology, structure and optical properties were investigated by X-ray diffraction, photoluminescence and UV-Vis spectra. The as synthesized ZnO QDs thin film showed a hexagonal wurtzite structure, having a size of 4-6 nm, in good agreement with the estimations from AFM and SEM images (Fig.1). The photoluminescence of the as-prepared ZnO QDs measured at the room-temperature exhibit an ultraviolet emission at 380 nm and a broad emission in the range of 420â&#x20AC;&#x201C;700 nm (Fig.2). In the absorption spectra determined on the thin layer spin-coated on quartz substrate the absorption in UV and its decrease at ~330 nm could be observed (Fig.3). Negative differential resistance was observed in a two terminal device in which the current can decrease with increasing voltage [3]. Current-voltage characteristics of ZnO QDs thin film spin coated on pre-patterned Cr/Au electrodes showed bipolar hysteretic response and two distinctive regions of negative differential resistance, recommending this material for memory devices development (Fig.4). Acknowledgements: This work was supported by the Romanian Program STAR contract no. 14/2012 and IMT-Bucharest Program Convert - project PN09290211. References [1] M.K. Patra, M. Manoth, V.K. Singh, G. Siddaramana Gowd, V.S. Choudhry, S.R. Vadera, N. Kumar, Journal of Luminescence 129 [2009] 320â&#x20AC;&#x201C;324; [2] A. H. Moharram, S. A. Mansour, M. A. Hussein, and M. Rashad, Journal of Nanomaterials, Volume 2014, Article ID 716210, http://dx.doi.org/10.1155/2014/716210; [3] Ya Yang, Junjie Qi, Wen Guo, Zi Qin, and Yue Zhang, Applied Physics Letters 96 [2010] 093107.

Figures

Fig.1 SEM and AFM image of ZnO QDs thin film prepared from a diluted solution

Fig.2 ZnO QDs photoluminescence for diluted solution and for a thin film

Fig.3 ZnO QDs absorption in a thin film

Fig.4 Current-voltage characteristics of ZnO QDs spin coated on pre-patterned Cr/Au electrodes

Innovation Ecosystems and Market Challenges in Nanobiotechnology and Nanomedicine: A multi-KET analysis within Horizon 2020 1

Cristina Paez-Aviles , Esteve Juanola-Feliu , Josep Samitier

1,2,3

Department of Electronics, Bioelectronics and Nanobioengineering Research Group (SIC-BIO), University of Barcelona, Martí i Franquès 1, Planta 2, Barcelona, Spain. cpaezeviles@el.ub.edu IBEC-Institute for Bioengineering of Catalonia, Nanosystems Engineering for Biomedical Applications Research Group, Baldiri Reixac 10-12, Barcelona, Spain 3 CIBER-BBN-Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, María de Luna 11, Edificio CEEI, Zaragoza, Spain 2

Abstract Horizon 2020 is the new European Commission’s initiative: the biggest financial program for Research and Innovation which goes “From fundamental research to market innovation” involving the entire innovation chain. With over 74 billion euros budget, H2020 searches turning scientific breakthroughs into innovative products and services [1]. Novelties of the framework include a risk management strategy through a Technology Readiness Level (TRL) seeking a major approximation to the market (Fig. 1). The program is composed by three pillars: Scientific Excellence, Society Challenges and Industrial Leadership. This last one aims to support SMEs in the industrial development and application of Key Enable Technologies (KETs), considered crucial accelerators for innovation and competitiveness [2]. Six KETs have been selected as the most strategically relevant: Nanotechnology, Biotechnology Industry, Advanced Materials, Micro & Nano Electronics and Advanced Manufacturing Systems. One of the most promising is Nanotechnology due to its economic and social growth potential [3]–[5]. Individually, each KET has a huge potential, however, their cross-fertilization is particularly important since their combination offer even greater possibilities to foster innovation and create new markets. The concept of cross-cutting KETs refers to the integration of different key enabling technologies in a way that creates value beyond the sum of individual technologies. The relevance of this combining process relies on the creation of new unique product properties and technology features, which could not have been possible to obtain with a single technology [6]. In the healthcare domain, nanobiotechnology and nanomedicine application areas of multiKETs in a short (2017) and medium term (2020), are principally based on more efficient and less invasive drugs and therapies, devices and systems for targeted diagnostics and personalized medicine, and smart systems and robots for healthcare services. In this context, the authors want to focus on the innovative performance and commercialization perspectives for healthcare applications and the challenges to reduce the gap between academic research and commercialization through a multi-KET case-study approach. Here is exposed a nano-enabled biomedical device composed with five of the six KETs, designed to be implanted under the human skin (Fig. 2). This is an innovative implantable device for in-vivo glucose monitoring of diabetic patients; an initial approach for the development of applications based on nanobiosensors for glucose threshold measurement. The global market volume in KETs is 646 billion € and substantial growth expected is approximately an 8% of EU GDP by 2015. About one third of the budget assigned to KETs will be address to support innovative projects integrating different KETs. By this year, it was expected that 16% of goods in healthcare and life sciences will incorporate emerging technologies [7]. Nanomedicine is considered a long-term play in the global market [8]; in fact, is anticipated to grow around 25% by year. Three major projecting areas in the healthcare field are nanodiagnostics, nanopharmaceutics and regenerative medicine. The expected market size related to radical innovation-based nanomedicines will be 1.000 M€ in 2020 and 3.000 M€ in 2025 [9]. In this context H2020 will spend 9.7% of the total budget in Health, Demographic Change and Wellbeing; specifically, the program will invest 3.851 M€ in Nanotechnology and 516 M€ in Biotechnology Industry [10]. Finally, an analysis of the state-of-the-art of nanomedicine and their innovation ecosystem within a 5-helix model approach is also analyzed to identify strengths and to improve weaknesses facing new scientific, market and societal challenges.

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15th edition of Trends in Nanotechnology International Conference TNT2014

References [1] Authors, Journal, Issue (Year) page. [1] E. Commission, “Preparing for our future: Developing a common strategy for key enabling technologies in the EU,” 2009. [2] ECSIP consortium, “Study on the international market distortion in the area of KETs: A case analysis,” no. May, 2013. [3] F. T. Rothaermel and M. Thursby, Res. Policy, 36 (2007) 832–849. [4] European Commission, Successful European Nanotechnology Research: Outstanding science and technology to match the needs of future society. 2011. [5] T. Flynn and C. Wei, Nanomedicine, 1 (2005) 47–51. [6] European Commission, 2013. [Online]. Available: http://ec.europa.eu/enterprise/sectors/ict/key_technologies/ro-ckets/index_en.htm. [Accessed: 19-May2014]. [7] Morrow Jr, R. Bawa, and C. Wei, Med. Clin. North Am., 91 (2007) 805–843. [8] K. Miyazaki and N. Islam, Technovation, 30 (2010) 229–237. [9] European Commission, “Roadmaps in Nanomedicine towards 2020,” 2009. [10] European Commission, “SME opportunities in Horizon 2020,” 2013.

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15th edition of Trends in Nanotechnology International Conference TNT2014

Nonequilibrium Carrier Dynamics of Si1-xGex nanowires measured by Optical Pump-THz Probe Spectroscopy 1,*

2,3

2,*

Jaehun Park Woo-Jung Lee , Hyejin Choi , Seonghoon Jung , Mann-Ho Cho 1

Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 790-784, Korea (ROK) 2 Department of physics and applied physics, Yonsei University, Seoul 120-749, Korea (ROK) 3 Electronics and Telecommunications Research Institute, 218 Gajeongno, Yuseong-gu, Daejeon 305700, Korea (ROK) jaehunpa@postech.ac.kr Abstract (Arial 10) Optical pump THz probe spectroscopy (OPTP)[1,2] is a powerful tool to study the nonequilibrium carrier dynamics of 1D/2D materials such as nanowires, phase transition materials, graphene, etc. occurring on ultrafast time scales. The basic understanding of carrier dynamics in nanostructures on ultrashort timescale[3-5] is getting important for the design of optoelectronic devices. In case of 1D NWs, the surface effect can no longer be ignored due to its large surface to volume ratio. Si1-xGex nanowires (NWs) were synthesized via a vapor-liquid-solid procedure using Au as a catalyst. The noneqilibrium carrier dynamics of Si1-xGex NWs as a function of Ge content was measured by optical pump-THz probe spectroscopy. From the meDVXUHG ǻ7 70 signal of Si1-xGex NWs, two carrier relaxation times of Ĳ1 (fast) and Ĳ2 (slow) were obtained and the optical properties of NWs at each Ge content were investigated. Factors which affect the carrier life time were discussed in this paper. We found that OPTP spectroscopy has a great potential to study the equilibrium/nonequilibrium dynamics as well as optical properties of 1D/2D materials. References [1] M. C. Beard, G. M. Turner, and C. A. Schmuttenmaer, Phys. Rev. B, 62 (2000) 15764 [2] P. Parkinson, J. Lloyd-Hughes, Q. Gao, H. H. Tan, C. Jagadish, M. B. Johnson, L. M. Herz, Nano Lett. 7 (2007) 2162 [3] J. H. Strait, P. A. George, M. Levendorf, M. Blood-Forsythe, F. Rana, J. Park, Nano Lett. 9 (2009) 2967 [4] R.P. Prasankumar, S. Choi, S. A. Trugman, S. T. Picraux, A. J. Taylor, Nano Lett. 8 (2008) 1619 [5] M. A. Seo, S. A. Dayeh, P. C. Upadhya, J. A. Martinez, B. S. Swartzentruber, S. T. Picraux, A. J. Tayor, R. P. Prasankumar, Appl. Phys. Lett. 100 (2012) 071104

Figures Figure 1. Schematic diagram of Optical pump-THz probe spectroscopy.

Figure 2. The measured 퓨7 7 RI WKH 6L1-xGex NWs as a function of Ge content.

Towards Self-Assembled Molecular Nanodielectrics on Ge and GaAs Lionel Patrone (1), Virginie Gadenne (1), Grégory Delafosse (1), Laure Fillaud (2), Bruno Jousselme (2), Volodymyr Malytskyi (1,3), Jean-Manuel Raimundo (3) (1) IM2NP, CNRS UMR 7334 Aix-Marseille Université, ISEN-Toulon, Maison des Technologies, Pl. G. Pompidou F-83000 Toulon, France (2) Laboratory of Innovation in Surface Chemistry and Nanosciences (LICSEN), DSM/IRAMIS/NIMBE CEA Saclay, F-91191 Gif-sur-Yvette Cedex, France (3) Aix-Marseille Université, CINaM UMR CNRS 7325, case 913, 13288 Marseille cedex 09, France contacting e-mail: virginie.gadenne@isen.fr, lionel.patrone@im2np.fr Abstract In the field of microelectronics, due to their high intrinsic mobility, germanium (Ge) and III-V semiconductors appear as promising alternative channel materials to replace silicon in the next generation of high mobility and high frequency transistors. However, contrary to silicon dioxide, those material oxides are neither stable nor of good quality. Preparing proper interfacial layer allowing to passivate and insulate Ge and III-V is one of the challenges still needed to be addressed. A promising way consists in using self-assembled molecular monolayers (SAMs) with a high dielectric constant, since it leads to uniform and nanostructurally well-defined robust thin film over large areas. It has been developed on silicon [1] but still remains to be applied on Ge and III-V. Therefore, the aim of this work is to design new SAMs grafted on Ge and GaAs exhibiting the best properties of insulation and passivation. Since thiol molecules have been shown to form SAMs on Ge [2] and GaAs [3], we use alkyl/ fluorinated/ and conjugated -thiol molecules. Specially synthesized conjugated molecules bear thiophene units either with a bithiophene-based push-pull polarizable molecule or a terthiophene-based model compound since push-pull monolayers are able to form a highly polarizable insulating film with dielectric constant (k = 7-8) significantly higher than that of silicon dioxide (k = 3.9) [1]. Obtained SAMs are first evaluated regarding their structure and organization. Moreover, since the interface has a direct influence on the electrical characteristics, it is essential to limit surface roughness to obtain a better interfacial layer with low defects. For this reason, as confirmed by scanning probe microscopy we have successfully developed a grafting process without acid treatment, contrary to most of Ge functionalization methods exploited in the literature, either in one-go [2], or within two steps, i.e., oxide removal followed by SAM grafting. The passivation ability of the various SAMs is first assessed by following by XPS the oxidation of Ge or GaAs surface functionalized by dodecanethiol and perfluorodecanethiol SAMs. Second, the electronic properties and insulation characteristics of the various SAMs (conjugated and alkyl or fluorinated with and without inserted conjugated molecules) are investigated by current-voltage and capacitance-voltage measurements, either at the nanoscale using scanning tunneling microscopy or at the microscale using eutectic GaIn electrical contacts, and analyzed notably by transition voltage spectroscopy [4]. We believe these results will help paving the way to developing new alternative high k dielectrics for the future generation of transistors. Support from ANR-11-BS10-012 (SAGe III-V project) and “Solutions Communicantes Sécurisées” (SCS) competitive cluster is acknowledged. References 1. Facchetti, M.H. Yoon, T.J. Marks, Adv. Mater. 17 (2005) 1705. 2. J.N. Hohman, M. Kim, H. R. Bednar, J.A. Lawrence, P.D. McClanahan, P.S. Weiss, Chem. Sci. 2 (2011) 1334 3. C.W. Sheen, J.X. Shi, J. Martensson, A.N. Parikh, D.L. Allara, J.Am. Chem. Soc. 114 (1992) 1514 4. I. Bâldea, Phys.Rev.B,85 (2012) 035442; J.M. Beebe et al., ACS Nano, 2 (2008) 827

Remote Plasma Enhanced – Chemical Vapor Deposition (rPE-CVD) of Graphene on Various Substrates 1

M. González Cuxart, I. Šics, M. J. U. Foerster, L. Aballe Aramburu, V. Carlino, 3, 4 4, 5 4, 5 1 A. R. Goñi, E. Pach, G. Sauthier, and E. Pellegrin 1 CELLS-ALBA, Carretera BP 1413, Km. 3.3, E-08290 Cerdanyola del Vallès (Barcelona), Spain 2 Ibss Group Inc.,1559B Sloat Blvd., Suite 270, San Francisco, CA 94132, USA 3 ICMAB,Campus de la UAB, E-08193 Bellaterra (Barcelona), Spain 4 ICREA, Passeig Lluís Companys 23, E-08010 Barcelona, Spain 5 ICN2 Campus de la UAB, Edifici ICN2, E-08193 Bellaterra (Barcelona), Spain mgonzalez@cells.es, epellegrin@cells.es, Abstract The electrical and mechanical properties of graphene, in particular ballistic electron transport properties, have opened up exciting possibilities for this material as a replacement for silicon. Graphene has a simple structure, consisting of a hexagonal arrangement of carbon atoms in a monoatomic layer (with a lattice parameter agr = 2,46 Å), and is mechanically and chemically stable. Mechanical exfoliation of highly oriented pyrolytic graphite (HOPG) has been the most common method of producing single layers of this material. However, the lateral dimensions of monolayer samples are typically limited to the micro-scale. Since large area graphene films on insulating substrates are required for practical applications, several techniques have been explored such as chemical vapor deposition (CVD) on transition metals, graphitization of SiC wafers under high vacuum, and reduction of oxidized graphite films. Recently, several authors [1-3] have reported new deposition methods using RF plasma as a way to decouple the dissociation process of the precursor gas from the graphene growth process onto the substrate via Plasma Enhanced Chemical Vapor Deposition (PE-CVD). It makes the method more tunable as it allows for an independent control of the reaction parameters and the growth parameters, which should lead to a better control of the size and shape of the nanostructures. Moreover, converting the precursor gas into a plasma state involves, by definition, a higher amount of active carbon radicals in the reaction process and thus enhances the deposition rate. By means of using a highly reactive deposition technique such as a hydrocarbon plasma, one can decrease the exposure time and/or decrease the substrate temperature. This latter feature opens the deposition process towards a wider variety of substrates with lower melting points. Last but not least, a remote plasma is – by definition generated at a distance from the substrate, thus minimizing preferential perpendicular growth directions that the electrical fields may induce in a traditional plasma setup. CELLS-ALBA together with ibss Group, Inc. has adapted the GV10x downstream inductively coupled RF plasma source typically used for cleaning hydrocarbon contaminated from SEM chambers to also remove carbon deposits on optical precision surfaces. For these applications the feedstock gas of the plasma consists of a chemically active agent such as oxygen or hydrogen converting carbon into CO2, CO, or hydrocarbons gas via a corresponding oxidation or reduction process, respectively. Our goal in this work has been to “reverse” the working principle of the GV10x, in order to convert it into a thin film deposition tool instead of a cleaning tool. This has been achieved by simply exchanging the feedstock gases, moving from oxygen or hydrogen to hydrocarbon gases that work as carbon sources which therefore become the precursors for the graphene deposition process. Carbon and CHx ions as well as radicals bond with the thermally activated substrate surfaces via H-bond breaking and H2 molecule formation, thereby eventually selfarranging in honeycomb graphite lattice geometry. In order to accomplish the purpose of reversing the working principle of the GV10x from a

top-down cleaning tool to a bottom-up deposition tool, several routes for depositing graphene on different substrates (e.g., Ni foil, HOPG) have been explored. After that, the resulting samples were characterized following a systematic approach in order to verify that indeed graphene was deposited, and, if so, its thickness, shape, etc. First of all, Raman spectroscopy gives an idea of the kind of carbon allotrope and crystalline quality. Scanning Electron Microscopy (SEM) gives a direct picture of the sample with a nanometric resolution, and finally X-Ray Photoemission Spectroscopy (XPS) gives a detailed chemical analysis of the surface that allows calculating atomic concentrations and graphene film thicknesses in terms of deposited monolayers. The main point of this characterization procedure has been to cross-check results and to obtain a more complete picture of the characteristics of our graphene samples.[4]

References [1] Y. B. Zhang, Y. W. Tan, H. L. Stormer, and P. Kim. Nature (London) 438, (2005), 201. [2] T. Otha, A. Bostwick, T. Seyller, and K. Horn, Science 313, (2006), 951. [3] Gopichand Nandamuri, Sergei Roumimov, and Raj Solanki. App. Phys. Lett. 96, (2010), 154101. [4] M. González Cuxart and E. Pellegrin, rPECVD of graphene on various substrates, thesis corresponding to the Master in “Nanotechnology and Materials Science”, Universitat Autònoma de Barcelona and ALBA-CELLS, (2014).

Figures

Figure 1: Conceptual layout of the RF plasma deposition chamber.

Figure 2: SEM image of one of our graphene samples.

Figure 3: Raman spectra corresponding to some of our graphene samples.

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empena@ull.edu.es ƵƌŝŶŐ ůĂƐƚ ĚĞĐĂĚĞ ĞŶŐŝŶĞĞƌĞĚ ŶĂŶŽƉĂƌƚŝĐůĞƐ ĂƌĞ ŝŶĐƌĞĂƐŝŶŐůǇ ĐŽŶƚĂŵŝŶĂƚŝŶŐ ǁĂƚĞƌƐ ĂŶĚ ŶĂƚƵƌĂů ĞĐŽƐǇƐƚĞŵƐ ĂŶĚ ƚŚĞŝƌ ƉŽƐƐŝďůĞ ƚŽǆŝĐŝƚǇ ƚŽ ŽƌŐĂŶŝƐŵƐ ŝƐ ƵŶĚĞƌ ĐĂƌĞĨƵů ƐƚƵĚǇ͘ dŚƵƐ͕ ŵĞĂŶƐ ŽĨ ĞĨĨŝĐŝĞŶƚ ƌĞŵŽǀĂů ŽĨ ƚŚĞƐĞ ƐƵďƐƚĂŶĐĞƐ Ğ͘Ő͘ ĨƌŽŵ ǁĂƚĞƌƐ ĂƌĞ ŚŝŐŚůǇ ŶĞĞĚĞĚ͘ ZĞĐĞŶƚůǇ͕ ŵĞƚĂů ŽƌŐĂŶŝĐ ĨƌĂŵĞǁŽƌŬƐ ;DK&ƐͿ ĂƌĞ ĐŽŶƐŝĚĞƌĞĚ ĂƐ ƉŽƚĞŶƚŝĂů ŵĂƚĞƌŝĂů ĨŽƌ ƚŚĞ ƐĞƉĂƌĂƚŝŽŶͬƌĞŵŽǀŝŶŐ ŽĨ ĚŝĨĨĞƌĞŶƚ ĐŽŶƚĂŵŝŶĂŶƚƐ ĨƌŽŵ ǁĂƚĞƌƐ͘ DK&Ɛ ŚĂǀĞ ƐŚŽǁŶ ƉŽƚĞŶƚŝĂů ĂƉƉůŝĐĂƚŝŽŶƐ ǁŝƚŚ ŐŽŽĚ ĂĐŚŝĞǀĞŵĞŶƚ ŝŶ ĐŽŵƉĂƌŝƐŽŶ ƚŽ ƚŚĞ ƚƌĂĚŝƚŝŽŶĂů ƉŽƌŽƵƐ ŵĂƚĞƌŝĂůƐ ƐƵĐŚ ĂƐ ǌĞŽůŝƚĞƐ ΀ϭ͕Ϯ΁͘ ŵŽŶŐ ĞŶŐŝŶĞĞƌĞĚ ŶĂŶŽƉĂƌƚŝĐůĞƐ͕ ƐŝůǀĞƌ ŶĂŶŽƉĂƌƚŝĐůĞƐ ; ŐEWͿ ĂƌĞ ƉůĂǇŝŶŐ ŵŽƌĞ ŝŵƉŽƌƚĂŶƚ ƌŽůĞ ĂƐ ĐŽŶƚĂŵŝŶĂŶƚ ŝŶ ĂƋƵĞŽƵƐ ĞŶǀŝƌŽŶŵĞŶƚ ΀ϯ΁͘ dŚĞ Ăŝŵ ŽĨ ƚŚŝƐ ǁŽƌŬ ŝƐ ƚŽ ƐƚƵĚǇ ƚŚĞ ŝŶƚĞƌĂĐƚŝŽŶ ŽĨ ƐŝůǀĞƌ ŶĂŶŽƉĂƌƚŝĐůĞƐ ǁŝƚŚ ƐĞůĞĐƚĞĚ DK&Ɛ͘ ^ŝůǀĞƌ ŶĂŶŽƉĂƌƚŝĐůĞƐ ǁĞƌĞ ƐǇŶƚŚĞƐŝǌĞĚ ƵƐŝŶŐ ĚŝĨĨĞƌĞŶƚ ƌĞĚƵĐŝŶŐ ĂŐĞŶƚƐ͘ ŽƉƉĞƌ ďĂƐĞĚ DK& ŶĂŵĞĚ ĂƐŽůŝƚĞZ ϯϬϬ ;^ŝŐŵĂ ůĚƌŝĐŚͿ ǁŝƚŚ ƚŚĞ ĨŽƌŵƵůĂ Ƶϯ ;ďƚĐͿϮ ;ǁŚĞƌĞ ďƚĐ ŝƐ ϭ͕ϯ͕ϱͲ ďĞŶǌĞŶĞƚƌŝĐĂƌďŽǆǇůĂƚĞͿ ǁĂƐ ƐƚƵĚŝĞĚ ĂƐ ƉŽƐƐŝďůĞ ƐŽƌďĞŶƚ ŵĂƚĞƌŝĂů ĨŽƌ ƚŚĞ ŶĂŶŽƉĂƌƚŝĐůĞƐ͘ ŝĨĨĞƌĞŶƚ ĞǆƉĞƌŝŵĞŶƚĂů ĐŽŶĚŝƚŝŽŶƐ ĂŶĚ ƐŽƌƉƚŝŽŶ ŝƐŽƚŚĞƌŵƐ ǁĞƌĞ ƐƚƵĚŝĞĚ͘ dŚĞ ĂĚƐŽƌƉƚŝŽŶ ŝƐŽƚŚĞƌŵ ŽĨ ŐEW ŽŶ ĂƐŽůŝƚĞ ƐƵƌĨĂĐĞ ǁĂƐ ĨŽƵŶĚ ŶŽŶůŝŶĞĂƌ͘ tŚĞŶ ĐŝƚƌĂƚĞ ĐĂƉƉĞĚ ŐEW ǁĞƌĞ ƵƐĞĚ ŝŶ ƚŚĞ ŝŶƚĞƌĂĐƚŝŽŶ ǁŝƚŚ ĂƐŽůŝƚĞ͕ ƚŚĞ ĨŽƌŵĂƚŝŽŶ ŽĨ ĚŝƐƉĞƌƐĞĚ ŐEW ŽŶ ƚŚĞ ƐƵƌĨĂĐĞ DK&Ɛ ƐƵƉƉŽƌƚ ǁĂƐ ĐŽŶĨŝƌŵĞĚ ďǇ ƚŚĞ ^ D ĂŶĂůǇƐŝƐ ;&ŝŐƵƌĞ ϭͿ ǁŚŝůĞ ƚŚĞ ŝŶĐŽƌƉŽƌĂƚŝŽŶ ŽĨ ŐEW ǁŝƚŚŝŶ ƚŚĞ ƉŽƌĞƐ ŽĨ DK&Ɛ ǁĂƐ ŶŽƚ ĐŽŶĨŝƌŵĞĚ͘ dŚĞ ĂŶĂůǇƐŝƐ ŽĨ ƚŚĞ ĞĨĨĞĐƚ ŽĨ ŽƌŐĂŶŝĐ ůŝŐĂŶĚ ŐƌŽƵƉ ;ďƚĐͿ͕ ƚŚĞ ƉŽƌĞ ƐƚƌƵĐƚƵƌĞ ĂŶĚ ĨƌĂŵĞǁŽƌŬ ĐŚĂƌŐĞ ŽŶ ƚŚĞ ŝŶƚĞƌĂĐƚŝŽŶ ŽĨ ŐEW ĂŶĚ ĂƐŽůŝƚĞ ƐƵƌĨĂĐĞ ǁĂƐ ƐƚƵĚŝĞĚ͘ dŚĞ ƌĞƐƵůƚƐ ĂĐŚŝĞǀĞĚ ĂŶĚ ŵĞƚŚŽĚŽůŽŐǇ ĚĞǀĞůŽƉĞĚ ŽƉĞŶ ƚŚĞ ƉŽƐƐŝďŝůŝƚǇ ĨŽƌ ĨƵƚƵƌĞ ƐƚƵĚŝĞƐ ŽĨ ƚŚĞ ƵƐĞ ŽĨ ĚŝĨĨĞƌĞŶƚ DK&Ɛ ĨŽƌ ƌĞŵŽǀŝŶŐ ŐͲ ŶĂŶŽƉĂƌƚŝĐůĞƐ ĨƌŽŵ ǁĂƚĞƌƐ͘ ĐŬŶŽǁůĞĚŐĞŵĞŶƚƐ

hŶŝǀĞƌƐŝƚǇ ŽĨ >Ă >ĂŐƵŶĂ Ͳ /ŶƚĞƌŶĂƚŝŽŶĂů ǆĐĞůůĞŶĐĞ ĂŵƉƵƐ ; /Ϳ ĂŶĚ 'ƌĂŶƚ D dϮϬϭϯͲ ϰϯϭϬϭZ ;DŝŶŝƐƚĞƌǇ ŽĨ ĐŽŶŽŵǇ ĂŶĚ ŽŵƉĞƚŝƚŝǀŝƚǇ͕ ^ƉĂŝŶͿ ĂƌĞ ĂĐŬŶŽǁůĞĚŐĞĚ͘ ^͘ ZǇďĂŬŽǀĄ ƚŚĂŶŬƐ ƚŽ ƌĂƐŵƵƐ WƌŽŐƌĂŵ͘ ZĞĨĞƌĞŶĐĞƐ ΀ϭ΁ YŝͲ>ŽŶŐ ŚƵ͕ :ƵŶ >ŝ ĂŶĚ YŝĂŶŐ yƵ͘ :͘ ŵ͘ ŚĞŵ͘ ^ŽĐ͘ ϭϯϱ ;ϮϬϭϯͿ ϭϬϮϭϬ͘ ΀Ϯ΁ ZŽŶĂůĚ :͘ d͘ ,ŽƵŬ͕ ĞŶũĂŵŝŶ t͘ :ĂĐŽďƐ͕ &ĂƌŝĚ ů 'ĂďĂůǇ͕ EŽĞů E͘ ŚĂŶŐ͕ ͘ ůĞĐ dĂůŝŶ͕ ĞŶŶŝƐ ͘ 'ƌĂŚĂŵ͕ ^ƚĞƉŚĞŶ ͘ ,ŽƵƐĞ͕ /ĂŶ D͘ ZŽďĞƌƚƐŽŶ͕ ĂŶĚ DĂƌŬ ͘ ůůĞŶĚŽƌĨ͘ EĂŶŽ >Ğƚƚ͘ ϵ ;ϮϬϬϵͿ ϯϰϭϯ͘ ΀ϯ΁ WĂŶǇĂůĂ E͘Z͕͘ WĞŹĂͲDĠŶĚĞǌ ͘D͕͘ WĞŹĂͲDĠŶĚĞǌ ͘D͘ :͘ ƉƉů͘ ŝŽŵĞĚ͘ ϲ ;ϮϬϬϴͿ ϭϭϳ͘ &ŝŐƵƌĞ ϭ Ϳ ^ D ŝŵĂŐĞ ŽĨ ƚŚĞ ƐĂŵƉůĞ ĐŽŶƚĂŝŶŝŶŐ ĂĚƐŽƌďĞĚ ŐEW ŽŶ DK& ƐƵƌĨĂĐĞ͘ Ϳ y ŝŵĂŐĞ ĚĞŵŽŶƐƚƌĂƚŝŶŐ ƌĂŶĚŽŵ ĚŝƐƉĞƌƐŝŽŶ ŽĨ ŐEW ŽŶ ƚŚĞ ƐƵƌĨĂĐĞ ŽĨ ƚŚĞ ďĂƐŽůŝƚĞ ĐƌǇƐƚĂůƐ͘

Assessment of carbon nanotubes-epoxy composite electrode for in-field detection applications Adriana Remes, Aniela Pop, Florica Manea Politehnica University of Timisoara, Romania aniela.pop@upt.ro; florica.manea@upt.ro Abstract Carbon nantubes-epoxy (CNT) composite electrode consisted of 20%, wt. CNT was electrochemically characterized envisaging its application for the in-field detection. CNT electrode was prepared by two-roll mill procedure and detailed description of preparation and morphostructural characterization was reported by our group [1]. The main peculiarity of an electrode for in-field detection application is to be able to respond without deliberately adding the supporting electrolyte that is required for conventional macroelectrode and as consequence, limits this kind of application. It is well-known that carbon based composite electrode can be regarded either ordered (array) or randomized micro/nanoelectrode ensembles [2]. Two characteristics are followed to characterize the ordered or randomized micro/nanoelectrode ensembles, i.e., the dependence of diffusion flux towards on the experimental timescale and the direct detection of the target analyte without supporting electrolyte adding. In the preparation of carbon-based composites with microelectrode array behaviour, certain important requirements should be met. The main requirement is that the gaps between individual conductive carbon microzones should be much larger than its radius, when spherical diffusion dominates mass transport. The closely spaced carbon microzones array will behave similar to a macroelectrode (linear diffusion controlled mass transport) because of the diffusion layer overlap [3]. Another requirement is subjected to the insulating matrix to prevent current leakage, which resulted in the distortion of the cyclic voltammetry [4]. Microelectrode arrays exhibit the advantages of single microeletrodes, e.g., reduced ohmic drop and charging current, the lower detection limit and better sensitivity. Based on the above-presented aspects, the electrochemical behavior of the CNT composite electrode was characterized by ferri/ferrocyanide classical method, and it was found that linear diffusion controlled the mass transport that is characteristics to the macroelectrode behaviour, with a substantial hysteresis. However, the ability to deliver the current responses in the absence of any supporting electrolyte, which is an attractive feature for practical in-field detection application, was tested using salicylic acid (SA) as target analyte. Two reasons subjected to SA selection as target analyte were taken into account, the first referred to direct analysis of pharmaceutical compounds in surface water as emerging pollutants envisaging indirect aspirin detection and the second issue referred to the certification of the micro/nanoelectrode array behavior of CNT composite electrode by SA detection in surface/tap water, without supporting electrolyte. Cyclic voltammetry was used for the electrochemical characterization of CNT composite electrode and differential-pulsed voltammetry (DPV) and square-wave voltammetry (SWV) for the detection experiments. The comparative responses obtained at CNT composite electrode using DPV technique in the absence/presence of 0.1 M Na2SO4 supporting electrolyte are presented in Figure 1 a and b, and it can be noticed that similar results were achieved. All electroanalytical parameters determined for SA detection under three variants of aqueous media (0.1 M Na2SO4 supporting electrolyte, surface water and tap water) are similar for each electrochemical technique. Based on these above-presented results, it can be concluded that MWCNT-EP composite electrode manifested the microelectrode array behavior in relation with the direct detection of SA in tap water, without supporting electrolyte. Moreover, the results of the SA detection direct in surface water, also without the supporting electrolyte adding show for this electrode a real potential for in-field detection application. .

Table 1. The comparative electroanalytical performance for SA detection using CNT electrode Aqueous media

Peak potential

0.1 M Na2SO4 supporting electrolyte

+0.52V

Bega River

+0.52V

+0.46V

+0.56V

Tap Water

+0.65V +0.52V

Technique Used/operation conditions DPV Sp=0.01V Ma=0.1V SWV Sp=0.005V Ma=0.05V F=50 Hz DPV Sp=0.01V Ma=0.1V SWV Sp=0.005V Ma=0.05 V F=50 Hz DPV Sp=0.01V Ma=0.1V

Concentration range (mM)

Correlation coefficient (R2) 0.994

LOD (mM)

LQ (mM)

0.2-1.2

Sensitivity (mA /mM1 ) 0.017

0.002

0.04

RSD [**] (%) 1.315

0.2-1.2

0.060

0.986

0.005

0.016

0.250

0.2-1.2

0.026

0.991

0.005

0.019

0.980

0.2-1.2

0.073

0.999

0.004

0.013

0.186

0.06-0.2

0.018

0.993

0.008

0.028

2.702

0.2-1.2

0.029

0.999

0.010

0.034

3.030

Acknowledgments This work has been supported by Romanian National Authority for Scientific Research, CNCSUEFISCDI within PNII-165/2011 and PNII-60/2012 grants. References [1] A. Remes, A. Pop, F. Manea, A. Baciu, S.J. Picken, J. Schoonman, Sensors , 12(6) (2012) 7033. [2] I. Corb, F. Manea, C. Radovan, A. Pop, G. Burtica, P. Malchev, S. Picken, J. Schoonman, Sensors, 7(11) (2007) 2626. [3] K. Stulik, C. Amatore, K. Holub, V. Marecek, W. Kutner, Pure Appl. Chem. 72 (2000) 1483. [4] B. Ballarin, M.M. Cordero-Rando, E. Blanco, J.L. Hidalgo-Hidalgo De Cisneros, R. Seeber, D. Tonelli, Collect. Czech. Chem. Commun. 68 (2003) 1420. Figures

a) b) Fig. 1. DPV recorded at CNT composite electrode in the presence of various SA concentrations in: a) 0.1 M Na2SO4 supporting electrolyte and b) tap water

Carbon nanomaterials as result of nanodiamonds annealing Vladimir A. Popov National University of Science and Technology ³MISIS´, Leninsky prospect, 4, Moscow, 119049, Russia popov58@inbox.ru Abstract Primary detonation nanodiamond (ND) particles have mainly of a close-to-spherical shape; however, particles of irregular shape (triangles, rods etc.) were also observed. The size of the nanodiamond particles is 2-20 nm with the size distribution maximum corresponding to 4±6 nm (about 90% of all particles). Primary ND particles were combined into agglomerates with size up to millimeters (Fig.1a). HRTEM showed that basic part of primary nanodiamond particles are single crystals, but essential portion of particles has different defects of crystalline structure: twins with {111} twinning plane, highangle boundaries between fragments of nanoparticle etc. Some defects can exist only in nanosized objects. For example, configuration as five-pointed star from twins leads to change of crystal parameters from the tabular values for bulk crystals (Fig.1b). ND annealing in vacuum or non-oxidized conditions leads to transformation into onion-like carbon nanoparticles [1]. Particles with defects of crystalline structure undergo transformation into carbon onions during annealing in vacuum at lower temperature than particles without structural defects. Investigation showed that basic part of nanodiamonds have diamond structure during annealing up to 950-1000 oC. Small part of nanodiamonds with size around 2 nm can transform into carbon onions at temperature 800 oC. After annealing of nanodiamond agglomerates at 1000-1300 oC, mixture of nanodiamonds and carbon onions is formed (Fig.1c). In temperature interval 1300-1500 oC, there is mixture of nanodiamonds with carbon onions, but with small volume fraction of nanodiamonds. Only carbon onions are present after annealing of nanodiamonds at 1500-1600 oC (Fig.2a). Mixture of carbon onions and graphenes is formed after annealing of nanodiamonds at 2000 oC (Fig.2a, b). Transformation of primary nenodiamond particle is depended from its size and position in agglomerate. Small particles (2-4 nm) and particles from surface of agglomerates transform more easily than big nanodiamond particles (6-20 nm) and particles in center of agglomerates. Figure3 shows results of EELS from central and surface parts of agglomerate after annealing at 1000 oC. One can see that surface area contents more graphite-like materials (sp2 bonding) than central area of agglomerate. It is necessary to control temperature of treatment during development of nanodiamond content materials. Acknowledgements The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under the EFEVE project, grant agreement 314582; and the Russian Foundation for Basic Research (Project No.12-08-00185). The author is grateful to C.Kuebel, D.Wang, A.V.Egorov, S.V.Savilov for assistance in the structure investigation.. References [1] V.A. Popov, A.V. Egorov, S.V. Savilov, V.V. Lunin, A.N. Kirichenko, V.N. Denisov, V.D.Blank, O.M.Vyaselev, T.B.Sagalova, J. Surface Investigation. X-ray, Synchrotron Neutron Techniques, 7 (6), (2013) 1034±1043. Figures Graphite-like structure

Diamond structure

2 nm a b Figure 1. Initial nanodiamonds (a, b) and ND after annealing at 1000 oC (c)

Graphenes

2 nm

2 nm a

Figure 2. Nanodiamonds after annealing at 1500-2000 oC: carbon onions after annealing at 1500 oC (a); mixture of carbon onions and graphenes (b, c)

sp2 peak

Direction of beam

sp2 peak

Surface area of agglomerate

Carbon onions (sp2 bonding)

Central area of agglomerate

a) Figure 3. EELS results: a) scheme of agglomerate; b) EELS from central area of agglomerate; c) EELS from surface area of agglomerate.

Giant Magnetoresistance with Temperature-dependent Crossover in FeNi3-graphene Nanocomposites G. Abellána, E. Coronadoa, H. Prima-García.*a a Instituto de Ciencia Molecular (ICMol), Universidad de Valencia. Catedrático José Beltrán 2, 46890 Paterna, Spain. Fax: +34 96 354 3273. Telf: +34 96 354 4419. E-mail: helena.prima@uv.es A dramatic temperature-dependent crossover from positive room-temperature Giant Magnetoresistance (GMR) to negative Low-field Tunneling Magnetoresistance (LFTMR) below 50 K is observed in FeNi3-graphene nanocomposites. Two clearly different behaviors have been discovered, being the temperature barrier ca. 50 K. The low-temperature behavior is particularly sensitive to low magnetic fields. The nanocomposites where synthesized by means thermal decomposition of a hybrid sebacate-intercalated layered double hydroxides as single source precursor. The as-synthesized nanocomposites consist on ferromagnetic FeNi3 nanoparticles embedded in a few-layers graphene matrix. This work represents a straightforward methodology based on chemical synthesis for the preparation of magnetoresistance materials offering great possibilities as GMR sensors.

Figure 1: Magneto-Resistance for 900ºC nanocomposite, and the zoom of the Low magnetic field range. All of our data suggest that we have a ferromagnetic nanoparticles/carbon matrix nanocomposite whose matrix conductivity can be tuned with temperature, thus offering the possibility of modulate the MR behavior. Moreover, all the rich MR phenomenology occurs under low fields. Our GMR granular nanocomposites can operate at room temperature or low fields in contrats to multilayered GMR materials, where a high magnetic field is required to saturate the MR, suggesting promising applications as GMR sensor

A comprehensive resistive memory characterization through the analysis of conductive filaments 1

J.B. Roldán, 1M.A. Villena, 1F. Jiménez-Molinos, 2E. Romera, 1P. Cartujo-Cassinello 1

Departamento de Electrónica y Tecnología de Computadores, Universidad de Granada, Facultad de Ciencias, Avd. Fuentenueva s/n, 18071 Granada, Spain

mavillena@ugr.es 2

Departamento de Física Atómica, Molecular y Nuclear and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain

ABSTRACT An in-depth characterization of thermal reset transitions in RRAMs has been performed by simulation. The simulator accounts for the electrical and thermal description of several coupled conductive filaments (CFs) as well as for the time-dependant filament destruction/creation mechanisms. All the equations involved in the device operation are solved self-consistently [1]. In addition, the CFs series resistance, including the contributions of the setup and Maxwell components, has been included in the calculations [2]. Using this simulation tool, we have reproduced I-V curves of several experimental devices. The reset voltage dependence on the initial resistance of the CF has been analyzed and the relevant role played by the CF shape has also been demonstrated. In this respect, devices with the same initial resistance but different CF shape can switch at different voltages. A simulation study of the reset voltage distribution obtained for these devices has also been performed in order to explain the variability of experimental samples. In this contribution we present a study of the influence of CF shape on device resistance, reset current and voltage, and maximum current. For our analysis we use filaments with truncatedcone shapes, which are known to be a good approximation to the real CF shapes [3]. As shown in [4], for Ni/HfO2/Si-n+ devices, there was found a big (tens of nanometers thick) filament, which is responsible for the main features of the reset process. For this reason, we study here a single filament structure, a good approach to characterize this kind of RRAM devices. The initial CF shape determines the evolution of the device in the reset process. For narrow CFs, the current flowing through the CF is small because the initial Maxwell and CF resistances are high. For this reason, a higher voltage is needed in order to undergo a reset event. References [1] M.A. Villena, F. Jimenez-Molinos, J.B. Roldán, J. Suñé, S. Long, X. Lian, F. Gámiz and M.Liu, “An in-depth simulation study of thermal reset transitions in RRAM”. J. Appl. Phys. 114, 144505 (2013). [2] R. S. Timsit, IEEE Trans. Compon. Packag. Technol. 22 (1), 85–98 (1999). [3] X. Wu, D. Cha, M. Bosman, N. Raghavan, D. B. Migas, V. E. Borisenko, X. Zhang, K. Li, and K. Pey, “Intrinsic nanofilamentation in resistive switching”, J. Appl. Phys. 113, 114503 (2013). [4] M. A. Villena, M. B. González, F. Jiménez-Molinos, F. Campabadal, J. B. Roldán, J. Suñé, E. Romera and E. Miranda, “Simulation of thermal reset transitions in resistive switching memories including quantum effects”, J. Appl. Phys. 115, 214504 (2014)

Figures

Fig. 1: Initial Maxwell resistance (left) and initial CF resistance (right) versus minimum CF radius. Maxwell resistance takes into account the funneling of current lines from the large metal electrodes to the narrow CF within the RRAM insulator [2]. All the CFs employed have truncated-cone shapes [3, 4].

Fig. 2: Reset voltage (left) and reset current (right) versus CF radii. The reset voltage is defined as the voltage applied just before CF gets broken. After the rupture event the current of the device is zero.

Fig. 3: Maximum current versus CF radii. Before the reset process takes place, the current is increased and consequently the filament temperature rises. When the critical temperature is achieved the current begins to drop off throughout the reset process.

Zitterbewegung in monolayer Silicene 1

E. Romera , J. B. Roldan and F. de los Santos

Departamento de Física Atómica, Molecular y Nuclear and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain 2 Departamento de Electrónica y Tecnología de Computadores & CITIC, Universidad de Granada. Fuentenueva s/n, 18071 Granada, Spain. 3 Departamento de Electromagnetismo y Física de la Materia, and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain eromera@ugr.es Abstract We have studied the current oscillations due to ZB in Silicene in a magnetic field by considering wave packets with a Gaussian population of both positive and negative energy levels. The ZB time is compared with other periodicities namely the classical period TCl and the revival times TR. As in previous studies [1,2,3,4] we find TZB < TCl< TR. A comparison of these phenomena with MoS2 and grapheme has been analyzed.

References [1] E. Romera and F. de los Santos, Phys. Rev. B 80 165416 (2009). [2] T. García, N. A. Cordero and E. Romera, Phys. Rev. B, 89, 075416 (2014). [3] T. García, S. Rodríguez-Bolívar, N. A. Cordero and E. Romera, J. Phys. Condens. Matter. 25, 235301 (2013). [4] E. Romera, J. B. Roldán and F. de los Santos, Phys. Lett. A 378, 2582 (2014).

Titanium Dioxide Nanofibers photosensitized with Porphyrin for Efficient Degradation of textile dyes in Water Rosales Maibelin, Yadarola Ciro, Zoltan Tamara Chemistry Centre, Venezuelan Institute for Scientific Research, (IVIC), Caracas, Venezuela. mrosales@ivic.gob.ve Abstract One-dimensional Titania nanostructures, as nanofibers (TNF) have been intensely studied because of the promising application of these materials in the field of destruction of pollutants in water, due to their high specific surface area, ion- exchange ability, low density and better optical properties. The capability to utilize TiO2 nanomaterials for these purposes arises from the enhanced reactivity of nanoparticulate TiO2 compared to that of the bulk material. In the specific case of heterogeneus photocatalysis, the photocatalytic activity of TiO 2 has been reported to depend on the size of the particles. In this study, pure titania nanofibers were synthesized using hydrothermal method. The photocatalytic degradation of methyl orange was studied, in the presence of TNF photosensitized with 5-(2hydroxy-5-methoxyphenyl)10-15-20-triphenyl porphyrin as photocatalyst. Scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and nitrogen adsorption techniques have been used to investigate the structure, morphology, crystalline structure and optical properties of TNF synthesized. The photochemical characterization was followed by production of singlet oxygen 1O2 species and .

reactive oxygen free radicals such as -O2 and [ OH]. The photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV-Vis light irradiation, and is possible to observe a complete degradation of methyl orange after 480 min of irradiation. The higher activity observed for the TNF photosensitized with porphyrin indicates improvement of the electron transfer between the sensitizer and the TNF in contrast to the TNF without modified. The studies show that TNF might be potential photocatalysts for the removal of dyes from wastewater. References [1] M.R. Hoffmann, S.T.Martin,W.Y. Choi, D.W. Bahnemann, Chemical Reviews, 95 (1995) 69. [2] J.G. Yu, S.W. Liu, H.G. Yu, Journal of Catalysis, 249 (2007) 59. [3] T. Kasuga, M. Hiramatsu, A. Hoson, T. Sekino, K. Niihara, Langmuir, 14 (1998) 3160. [4] T. Kasuga, M. Hiramatsu, A. Hoson, T. Sekino, K. Niihara, Advanced Materials, 11 (1999) 1307. [5] H. D. Jang, S. K. Kim, S. J. King, Journal of Nanoparticle Research, 3 (2001) 141. Figures

Figure 1. SEM image TiO2 Nanofibers

O22.-.- .-.O O22 O O22.-.- O .-.O O22 ..O O22 O O22.-.-

hv hv

Excitation

1O 2

1(Sen)*

TiO2 hv

3(Sen)*

Photosensitizer

H20

Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+ Ú2+

(Sen)0

Figure 2. Schematic diagram of photocatalytic mechanism

Synthesis of fullerene on the surface of carbon nanoparticle by arc discharge method M. Reza Sanaee and Enric Bertran FEMAN Group, Institute of Nanoscience and Nanotechnology (IN2UB), Dept. Applied Physics and Optics, Universitat de Barcelona, MartĂ FranquĂ¨s, 1, E08028 Barcelona, Spain sanaee@ub.edu

Fullerenes materials have received wide attention due to their biomedical applications such as photodynamic therapy and magnetic resonance imaging [1]. The major limitations of realizing the practical applications of fullerenes are high cost and low production yield [2]. The arc discharge is well known technique for synthesis of carbon base materials. Here, we report the synthesis of fullerene on the carbon nanoparticle surface (FOCNPs). The precursor component and its new delivery system allowed a facile and continuous synthesis; which increased the production yield in comparison with previous arc discharge designs [3]. FOCNPs were observed and analyzed by high resolution TEM. The carbon structure along the periphery were thin enough for observation of a single fullerene molecules structure that were fullerenic. Similar fullerenic structure have been obtained by other methods and are reported in literatures [4, 5].

1. Partha R and Conyers JL, International journal of nanomedicine. 4 (2009) 261. 2. Wang J, Hu Z, Xu J and Zhao Y, Nature publishing group asia materials. 6 (2014) e84. 3. Aguayo N A. University of Barcelona, (2012). 4. Goel A, Howard JB and Vander Sande J B, Carbon, 10 (2004) 1907-15. 5. Goel A, Hebgen P, Vander Sande J B and Howard J B, Carbon, 2 (2002) 177-82.

Enhanced Thermal Oxidation Stability of Reduced Graphene Oxide by Nitrogen Doping.

Stefania Sandoval, Nitesh Kumar, A. Sundaresan, C. N. R. Rao, Amparo Fuertes and Gerard Tobias 1

Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra (Barcelona), Spain 2 JNCASR, Jakkur P.O., Bangalore- 560064 e-mail: ssandoval@icmab.es

Nitrogen-doped reduced graphene oxide (N-doped RGO) samples with a high level of doping, up to 13 wt.Ԝ %, 1 have been prepared by annealing graphene oxide under a flow of pure ammonia gas. The reaction of GO with NH3 was investigated at different temperatures (500±800 ºC), treatment times (10-300 min, including -1 different heating programs), and flow rates of ammonia (between 60 and 600 mLmin ). Samples with different nitrogen contents have been characterized by scanning electron microscopy, elemental and thermogravimetric analysis and X-ray photoelectron spectroscopy. The presence of nitrogen within the 2 structure of RGO induces a remarkable increase in the thermal stability against oxidation by air. The thermal stability is closely related with the temperature of synthesis and the nitrogen content. The combustion reaction of nitrogen in different coordination environments (pyridinic, pyrrolic, and graphitic) is analyzed against a graphene fragment (undoped) from a thermodynamic point of view. In agreement with the experimental observations, the combustion of undoped graphene turns out to be more spontaneous than when nitrogen atoms are present. This work opens up new possibilities for tailoring the properties of graphene and related systems, further expanding their range of application, for instance in synthesis of reinforcing material in components exposed at elevated temperatures and friction, and to prepare catalysts with applications in fuel 3 cells.

References (1) Daniela C. Marcano, D. V. K., Jacob M. Berlin, Alexander Sinitskii, Zhengzong Sun,; Alexander Slesarev, L. B. A., Wei Lu, and James M. Tour ACS Nano 2010, 4, 4806. (2) Sandoval, S.; Kumar, N.; Sundaresan, A.; Rao, C. N. R.; Fuertes, A.; Tobias, G. Chemistry ± A European Journal 2014, 20, 11999. (3) Xin, Y.; Liu, J.-g.; Jie, X.; Liu, W.; Liu, F.; Yin, Y.; Gu, J.; Zou, Z. Electrochimica Acta 2012, 60, 354.

Polarization-Resolved Near-Field Mapping of Nanoscale (Ȝ0/310) IR Transmission Line Modes 1

1,2

M. Schnell , P. Sarriugarte , A. Chuvilin , R. Hillenbrand

1,2

CIC nanoGUNE and UPV/EHU, 20018 Donostia ± San Sebastian, Spain 2 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain schnelloptics@gmail.com

Abstract Metal antennas and transmission lines (TL) are common devices for receiving and transporting signals in the radiofrequency regime. It has been demonstrated that by reducing the size down to the micrometer range, these devices can be operated at infrared frequencies (~30 THz) [1-3]. Here we demonstrate that functional infrared TLs with gap widths down to 25 nm can be fabricated by Gallium Focused Ion Beam (FIB) milling of gold films on CaF2 substrates [1]. Interferometric and polarization-resolved near-field microscopy [4] is applied to map in real space the propagation of the TL modes. For the first time, we measured the strongly confined fields of a propagating TL mode by mapping the s-polarized scattered field. Imaging TLs with 25 nm gap width we experimentally demonstrate an infrared mode with diameter of Dm = 42 nm (Ȝ0/220), which intriguingly, shows a propagation length of about Lm = 8 ȝm. Interestingly, this is more than two orders of magnitude larger than the mode diameter, Lm/Dm = 190. Applying combined Gallium and Helium FIB milling, we fabricated infrared TLs with single-digit nanoscale gap widths. Imaging a TL with 5 nm gap width we experimentally demonstrate an infrared mode with a diameter of only Dm = 30 nm (Ȝ0/310) and a propagation length of about Lm = 2 ȝm (Fig. 1). Numerical calculations predict signifiFDQW SURSDJDWLRQ GLVWDQFHV ! ȝP IRU HYHQ VPDOOHU JDSV GRZQ WR 1 nm width. TLs comprising such nanoscale wire-separation could become highly valuable building blocks for ultra-sensitive mid-infrared sensing, spectroscopy and nanoimaging applications. References [1] P. Sarriugarte et al., ACS Photonics 1, 604-611 (2014). [2] M. Schnell et al., Nat. Photonics 5, 283-287 (2011). [3] P. Sarriugarte et al., Opt. Comm. 285, 3378-3382 (2012). [4] M. Schnell et al., Nano Lett. 10, 3524 (2010).

Figures (a)

(b)

(c)

(d)

Fig. 1: Near-field imaging of a transmission line (TL) with a 5 nm gap. (a) Experimental near-field image showing the real part, Re(Ep). (b) Experimental near-field amplitude image |Es| superposed on the SEM image (grey color). (c) Numerically calculated mode profile. (d) Nearfield amplitude |Es| perpendicular to the TL extracted along the dashed lines in (b,c) (dots: experimental data, line: calculation), revealing an infrared mode diameter of only 30 nm. ,PDJLQJ ZDYHOHQJWK ZDV Ȝ0 = 9.3 ȝP

Facile Electrochemical Template Synthesis of CoPt Alloyed Mesoporous Nanorods from Microemulsions Using an Ionic Liquid Albert Serrà, Elvira Gómez, Elisa Vallés *UXS G¶(OHFWURGHSRVLFLy de Capes Primes i Nanoestructures (Ge-CPN), Departament de Química Física 2 and Institut de Nanociència i Nanotecnologia (IN UB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona. a.serra@ub.edu Abstract The developments of nano-size materials (nanoparticles, nanorods, nanospheres, among others) are undeniable, reaching applications from catalysis to biomedicine or information storage due to their [1] unique chemical and physical properties . Nanomaterials provide an enormous challenge in energy conversion and storage devices due to their effectiveness as electrocatalysts for methanol (DMFCs) or ethanol (DEFCs) fuel cells. Nowadays, the major advances in the fabrication of nanocatalysts are focused on enhancing durability and electrocatalytic activity by increasing both the surface ±volume ratio and the catalytic performance [2]. In this direction, one of the challenges of the synthesis methods is the preparation of controlled nano or mesoporous nanostructures as a consequence of their high porosity and surface-volume ratio. Mesoporous nanomaterials can be prepared by several methodologies including the traditional hardtemplating, phase separation, and alloy-dealloying approaches, among others [3]. Recently, soft [4] template systems have been proposed as a new approach . Therefore, a facile and generalizable synthesis pathway to produce ordered and controlled mesoporous is a new burgeoning challenge. Herein we propose a new, facile, versatile, environmentally friendly, simple, inexpensive procedure for the synthesis (Figure 1) of porous nanostructures (nanorods) of metals or alloys, from confined electrodeposition using microemulsions containing aqueous solution (W), Ionic Liquid (IL) and Surfactant (S). This method allows producing alloyed nanorods of variable porosity as a function of the microemulsion structure (ionic liquid-in-water (IL/W), bicontinuous or water-in-ionic liquid (W/IL)). This original method successively permits the growth of nanorods with extremely porosity. The prepared nanorods (of CoPt alloy) present a very high value of the effective area for mass unity, significantly higher than that corresponding to other platinum nanostructures (compact nanorods, Pt nanoparticles), which makes them very catalytic for methanol oxidation. The proposed approach is obviously nonrestricted to the CoPt system. However, we select CoPt because bimetallic platinum alloys with less expensive 3d-transition metals (Fe, Co, and others) enhance the electrochemical activity for methanol oxidation (reduction of poisoning by adsorbed intermediates) and reduces costs [5]. Therefore, iW¶V D general method, able to prepare very porous nanostructures of different metals or alloys, by preparing stable microemulsions with ionic liquids in which the aqueous component can be any classic electrolytic bath. Moreover, the nanorods present a very good corrosion resistance and stability, as the manner that they can be presented as very promising electrocatalysers. The obtained nano or mesoporous nanorods exhibit high electrocatalytic activity and corrosion stability, a facile recyclability by the anchoring or recollecting due to their magnetic behavior and a relatively good poison tolerance in the methanol oxidation, which make them highly promising electrocatalysts in the future. References [1]

Q. Xiang, J. Yu, M. Jaroniec. Journal of the American Chemical Society 134 (2012) 6575.

[2]

C. Hsu, C. Huang, Y. Hao, F. Liu, Electrochemistry Communications 23 (2012) 133.

[3]

T. W. Kim; I. D. Park, R. Ryoo. Angewadnte Chemie 115 (2003) 4511.

[4]

D. Wang, H. Luo, R. Kou, M. P. Gil, S. Xiao, V.O. Colub, Z. Yang, C. J. Brinker, Y. Lu. Angewadnte Chemie 116 (2004) 6295.

[5]

J. R Antolini, C. Salgado, E. R. Gonzalez, Applied Catalysis B 63 (2006) 137.

Figures

Figure 1: Schematic representation of the different selected systems (aqueous solution and ionic liquidin-water, bicontinuous or water-in-ionic liquid microemulsions) and HRTEM micrographs.

Surface Functionalization of Magnetic Nanoparticles for Biomedicine Anna Szelag, Emerson Coy, Blazej Scheibe, Stefan Jurga NanoBioMedicial Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland anna.szelag@amu.edu.pl

Abstract

Magnetite nanoparticles (Fe3O4) exhibit the unique electric and magnetic properties based on the 2+ 3+ transfer of electrons between Fe and Fe in the cubic sites. Due to the unique properties and advantages of magnetite, such as strong magnetism, good biocompatibility, long durability, low toxicity and low cost, it is widely used in magnetic biomedicine [1±3], heavy metal ions removal, electromagnetic wave absorption and other fields [4-6]. Most of these applications require Fe3O4 NPs to be chemically stable, biocompatible and highly dispersible in various pH liquid media. In order to meet all above mentioned requirements, adding a coating to Fe3O4 NPs is the most common approach. This fact changes their surface properties and prevents direct contact between the Fe3O4NPs.

Figure 1. Modification of Magnetic Iron Nanoparticles (INPs). In this work, magnetite nanoparticles were synthesized by chemical co-precipitation of FeCl2 ‫ ڄ‬4H2O and FeCl3 ‫ ڄ‬6H2O using hydroxide ammonium as precipitants. The chemical co-precipitation method was selected for its simplicity, convenience, reproducibility, and low cost in the use of glassware. The nanostructured materials were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Iron nanoparticles were modified (Fig. 1) with TEOS as precursor of silica and polyvinylpirolidone (PVP) as surfactant. The objective of this work is to study the variation in the morphological characteristics and physical properties of obtained nanoparticles before and after modification as a function of the different production processes.

References [1] F.H.Chen, L.M.Zhang, Q.T.Chen,Y.Zhang, Chemical Communications 46, (2010) 8633-8635. [2] Y. Chen, H.Y. Chen, D.P. Zeng, Y.B. Tian, F. Chen, J.L. Shi, ACS Nano 4 (2010) 6001±6013. [3] F.Y. Cheng, C.H. Su, Y.S. Yang, C.S. Yeh, C.Y. Tsai, D.B. Shieh, Biomaterials 26 (2005) 729±738. [4] L.Z. Shen, Y.S. Qiao, Y. Guo, J.R. Tan, Journal of Hazardous Materials 177 (2010) 495±500. [5] H.W. Wang, H.C. Liu, International Journal of Applied Ceramic Technology 7 (2010) E33±E38. [6] A.S. Teja, P.Y. Koh, Progress in Crystal Growth and Characterization of Materials 55 (2009) 22±45.

Computer simulations of nanosized biomaterials Antonio Tilocca Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK a.tilocca@ucl.ac.uk Abstract Bioactive glasses such as 45S5 (45 SiO2, 24.5 Na2O, 24.5 CaO, 6 P2O5 wt%) are clinically employed as bone defect fillers in orthopaedic and dental applications. Their potential for regenerative medicine has also been highlighted but not exploited as yet, due to the limited fundamental understanding of their composition-structure-activity relations. For instance, nanosized BG45 particles have shown enhanced biological activity and antibacterial properties, which could be the key towards developing a new generation of biomaterials for regenerative medicine. However, the rational development of these materials requires a better understanding of the origin of the superior properties of BG45 nanoparticles. Computer simulations are playing an increasingly important role in this field. [1,2] Molecular Dynamics simulations of a Bioglass spherical nanoparticle (approximately 6 nm diameter) have been carried out to investigate how the reduced size affect structural and dynamical features, which could enhance the bioreactivity of these systems (Fig.1). Compared to the bulk glass or to the 2D-flat surface of BG45,[3] the simulations reveal that the reduced size leads to: (i) a further slight reduction in the already low silicate connectivity on the nanoparticle surface; (ii) to a ring size distribution shifted towards threemembered rings; (iii) and to a higher Na+/Ca2+ ratio in close proximity of the surface. A higher mobility of Na cations in the external regions of the nanoparticle has also been detected. The possible ways in which these effects can translate into higher bioreactivity of BG45 nanoparticles are discussed. References [1] A. Tilocca, J. Mater. Chem., 21 (2011) 2660. [2] A. Tilocca, PCCP 16 (2014) 3874. [3] A. Tilocca and A. N. Cormack, Langmuir, 26 (2010) 545. Figures

Fig.1: An atomic-scale model of a 45S5 bioactive glass nanoparticle obtained through Molecular Dynamics simulations.

On Channel Shape Variation of 10-nm-Gate Gate-All-Around Silicon Nanowire MOSFETs

1,2

1,3

1,3,*

Saurabh Tomar , Pei-Jung Chao , Han-Tung Chang , and Yiming Li 1

Parallel and Scientific Computing Laboratory, National Chaio Tung University, Hsinchu 300, Taiwan Grenoble Institute of Technology - PHELMA, 3 Parvis Louis NEEL, 38016 GRENOBLE Cedex, France 3 Institute of Biomedical Engineering, National Chaio Tung University, Hsinchu 300, Taiwan * Tel: +886-3-5712121 Ext. 52974; Fax: +886-3-5726639; E-mail: ymli@faculty.nctu.edu.tw

Abstract Recently, gate-all-around (GAA) nanowire field effect transistors (NWFETs) have attracted increasing attention due to their superior gate control and short channel effect immunity [1-4]. However, confined by the limitation of manufacturing process, the different aspect ratio (AR) results in different shapes of channel cross section, such as ellipse-shaped or rectangular-shaped instead of the ideal round-shaped and square-shaped, respectively [5-8]. In this study, we analyze the effects on 10-nm-gate single- and multi-channel GAA silicon NWFETs with different geometry of cross-section, including AR and radius variation by applying an experimentally validated three-dimension (3D) quantum correction simulation. We point out that an ellipse-shaped GAA NWFETs having relatively smaller AR of radius owns better electrical characteristics. As the technology nodes have channel length in nanoscale regime, therefore, it becomes necessary to include quantum mechanical effects when modeling any FETâ&#x20AC;&#x2122;s terminal property. To model the quantum mechanical effects, we adopt a computationally cost-effective simulation model which consists of drift-diffusion equations with doping-/field-dependent, channel orientation dependent, and surface roughness mobility for the carrierâ&#x20AC;&#x2122;s transport and density-gradient equations for various quantum mechanical effects [9]. The computational architecture of the 3D single-channel NWFET and cross-section views of channel are shown in Fig. 1(a). Figure 1(b) shows the achieved electrical characteristics of single-channel GAA NWFETs. In the case of AR = 0.5, the value of its subthredshold swing (SS) and drain induced barrier -1 -1 lowering (DIBL) is 66 mVdec and 68 mVV , respectively, and the order of magnitude of Ion/Ioff ratio -1 reaches 6. However, for the case of AR = 2, has SS and DIBL are considerably larger at 116 mVdec -1 and 113 mVV , respectively and the Ion/Ioff ratio is in the order of 4. It is obvious that when the AR decreases, the device shows better channel controllability. In addition, the device with a smaller AR demonstrates better operating characteristics and suffers from less short-channel effects. Figure 2 illustrates a transformation between ellipse to circle shaped cross-section of effective radius Reff and corresponding ID-VG characteristics. As can be seen, the device with the smallest Reff has the best Ion/Ioff ratio of all, but the case of the largest Reff (i.e. AR = 2) has the worst. This improvement is attributed to the effective gate control due to relatively smaller radius of the cross-section. For multichannel cases, we focus on the two-channel devices. Figure 3(a) is the 3D two-channel NWFET structure and its corresponding cross-section views respectively. The case of two-channel with AR equal to 0.5 has the best short-channel effect parameters (i.e. Ion/Ioff ratio, SS, and DIBL), which is shown in Fig. 3(b) among all the six cases. It also improves upon the values as compared with the single-channel case with AR = 0.5, while opposite is true for dual channels with AR = 2. Furthermore, it can be seen that two-channel case with both AR equal to 2 has the worst properties. The order of the Ion/Ioff ratio of it has degenerated to 3, and the DIBL is even worse. Consequently, the ability of suppressing short-channel effect of the structure with smaller AR is much better than that with the larger one. In summary, electrical characteristic of 10-nm-Gate silicon NWFET with various process variation of channel radius has been studied. We are currently studying NWFET with different channel materials. Acknowledgements: This work was supported in part by Ministry of Science and Technology, Taiwan Under Contract No. NSC-102-2221-E-009-161, and by tsmc, Hsinchu, Taiwan under a 2012-2013 grant.

References [1] R.-H. Baek, D.-H. Kim, T.-W. Kim et al., Symp. VLSI Tech., pp. 210-211, 2014. [2] S. H. Shin, M. Masuduzzaman, J. J Gu et al., Tech. Digest IEDM, pp. 188-191, 2013. [3] S. Bangsaruntip, K. Balakrishnan, S.-L. Cheng et al., Tech. Digest IEDM, pp. 20.2.1-20.2.4, 2013. [4] A. Majumdar, S. Bangsaruntip, G.M. Cohen et al., Tech. Digest IEDM, pp. 8.3.1-8.3.4, 2012. [5] L. Zang, L. Li, J. He, and M. Chan, IEEE Electron Device Letters, vol. 32 (2011), pp. 1188-1190. [6] Y. Li and C.-H. Hwang, Semiconductor Science and Technology, vol. 24, (2009) 045004. [7] Y. Li, H.-M. Chou, and J.-W. Lee, IEEE Transaction on Nanotechnology, vol. 4 (2005), pp. 510-516. [8] H.T. Chang and Y. Li, Tech. Proc. 2014 NSTI Nanotech. Conf. & Expo, vol. 3 (2014), pp. 5-8. [9] M.G. Ancona, Journal of Computational Electronics, vol. 10 (2011), pp. 65-97. Figures

Figure 1. (a) Three-dimensional plot of single-channel GAA nanowire transistor structure and the crosssectional views with different AR equal to (l) 0.5, (ll) 1, and (lll) 2, respectively. The testing device has gate length LG= 10nm and oxide thickness Tox= 0.8nm. (b) Electrical characteristic of the device for different AR.

Figure 2. (a)-(c) The elliptical cross-section transformations to a circular shape of effective radius Reff. The right plot shows the ID-VG curves of the single channel NWFET for different AR and effective radius.

Figure 3. (a) Multi-channel Si NWFET with different AR equal to (l) 1 and 1, (ll) 0.5 and 0.5, (lll) 2 and 2, (IV) 1 and 0.5, (V) 1 and 2, and (Vl) 0.5 and 2, respectively. (b) Electrical characteristic of the device for different AR.

Electrochemical synthesis of CoPt nanoparticles over carbonaceous substrates for electrocatalysis Elisa Vallés, Elvira Gómez, Sergi Grau, Juan M. Feliu, Manuel Montiel Dpt. Química Física, Facultat de Química, Universitat de Barcelona, martí i Franquès 1, 08028 Barcelona, Spain e.valles@ub.edu Abstract The electrochemical technology is demonstrated as a useful procedure to fabrication of micro or nanostructures of metals and alloys, approaching to the Nanoscience and Nanotechnology field. In our laboratory, we develop different electrochemical strategies for the synthesis of nanoparticles, from a few nanometers to tens of nanometers, core@shell nanoparticles, nanowires with modulated aspect-ratio, nanotubes or nanometric films. Herein we describe the fabrication of CoPt nanoparticles with two different structures: CoPt alloy nanoparticles over glassy carbon or carbon cloth, and core@shell Co@Pt nanoparticles over glassy carbon (GC) substrate. These structures can be useful as electrocatalyzers for methanol oxidation in acidic or basic medium. We have demonstrated that it is possible to fabricate CoPt alloy nanoparticles of a few (3-4 nm) nanometers and variable composition, from chemical reduction in water-in-oil microemulsions [1]. These NPs show a discrete electrocatalytic behavior respect to oxalic electro-oxidation, especially those corresponding to Pt3Co. We demonstrate now that the electrochemical methods allows preparing CoPt alloy nanoparticles of greater size on different carbonaceous substrates, as the manner that the resulting structures could be directly used for electro-catalytic activity. By direct electrodeposition from electrolytic baths containing Co(II) and Pt(IV) salts, we have fabricated dense distributions of CoPt alloy NPs over both glassy carbon and carbon cloth substrates. The strict control of the deposition technique (continuous or pulsed electrodeposition), applied potential, and deposition charge permit to control the size, distribution and composition of the NPs (Figure 1). The best electrocatalytic behavior respect to methanol oxidation in acidic medium (H2SO4) is for Pt3Co. Co@Pt NPs have been fabricated electrochemically on glassy carbon substrates, by means cobalt deposition with a strict control of the deposition charge and deposition potential to induce the formation of homogeneously distributed isolated cobalt particles (Figure 2). The cobalt particles formed has been immersed in platinum (IV) solution in order to induce the displacement between the superficial cobalt or cobalt oxide and the platinum. The control of the shell of platinum formation has been performed electrochemically, by following the electrochemical profile of the materials in a blank solution. This CoPt particles present better electrocatalytic behavior for methanol oxidation in basic media that pure platinum particles of the same size supported over glassy carbon.

References [1] J. Solla-Gullon, E. Gómez, E. Vallés, A. Aldaz, J.M. Feliu, Journal of Nanoparticles Research 12 (2010) 1149

Figure 1: CoPt (Pt3Co) nanoparticles electrodeposited on GC substrate, and their electro-catalytic activity respect to methanol oxidation in acidic medium

Figure 2: Co nanoparticles electrodeposited on GC substrate and voltammetric response, at 50 mV s-1, of the Co@Pt core@shell nanoparticles in NaOH 0.1 M + Methanol 0.4 M solution (solid line) and NaOH 0.1 M + Methanol 0.8 M solution (dashed line). Recovery of the nanoparticles with a shell of Pt. Dotted line: NaOH 0.1 M

Graphene microelectrode arrays for cell stimulation Damià Viana Casals, Martin Lottner, Michael Sejer Wismer, Felix Rolf, Lucas Hess and Jose Antonio Garrido Walter Schottky Institut, Am Coulombwall 4, Technische Universität München, 85748 Garching, Germany damia.viana@wsi.tum.de Abstract The direct electrical interfacing of graphene-based devices with individual neurons is currently being considered for the development of the next generation of neuroprosthetic devices. Electrical stimulation of neurons can be carried out by voltage-sensitive transmembrane proteins called ion channels embedded in the cell membrane. By modulating the outer potential appropriately it is possible to externally stimulate electrogenic cells. Typically, external stimulation of neural tissue is done using electrodes in direct contact with biological tissue. To date, electrodes have been basically metallic and triggered Faradaic currents, whose reactive redox products could damage the cells. An alternative [1] way to depolarise cells externally is through capacitive currents , which require chemically stable electrodes and do not have the problems associated to redox reactions typical of metal electrodes. Graphene is a very good candidate for external capacitive stimulation of electrogenic cells due to its remarkable chemical and physical properties. Because of its high stability in aqueous environments, no surface layer of dielectric material is required to insulate it from the solution in order to prevent 2 unwanted electrochemical reactions. In addition, its high capacitance up to 2 µF/cm makes graphene an ideal candidate for capacitive stimulation. Furthermore, graphene is known to possess good biocompatibility and facility to be integrated in flexible devices, which is crucial in neuroprosthetic [2, 3] applications . This work will provide a detailed description of the fabrication of chips containing arrays of graphene based solution-gated field-effect transistors (G-SGFET) and microelectrodes (G-MEA) and their use for recording and stimulation of action potentials in cell cultures. Chips (Fig. 1) are fabricated using high quality graphene grown by CVD and standard optical lithography, e-beam and thermal evaporation of metals and oxygen plasma etching. For the characterisation of the devices, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and transistor characterisation at different values of pH and ionic strength are performed. Moreover, electrogenic cells (PC12, HEK and HL-1) are cultured on the graphene chips according to established protocols. Once the devices are fabricated and characterised, mature cells are placed onto them and bioelectronic experiments are performed. Using the patch clamp technique and the arrays (Fig.2) it is possible to record changes of intracellular potential and depolarise cells. The obtained data is finally processed and the triggered action potentials identified (Fig. 3).

References [1] Schoen, I., Fromherz, P., Extracellular stimulation of mammalian neurons through repetitive activation of Na+ channels by weak capacitive currents on a silicon chip, J Neurophysiol 100, 346 (2008). [2] Hess, L. H., Jansen, M., Maybeck, V., Hauf, M. V., Seifert, M., Stutzmann, M., Sharp, I. D., Offenhäusser, A. and Garrido, J. A., Graphene Transistor Arrays for Recording Action Potentials from Electrogenic Cells, Advanced Materials 23, 5045 (2011). [3] Hess, L.H., Seifert, M. and Garrido, J.A., Graphene Transistors for Bioelectronics, Proceedings of the IEEE 100, 1780 (2013).

Figures

Fig. 1. Optical micrograph of an array with 12 circular electrodes (diameter from 25 µm to 100 µm) and 4 transistors (15x35 µm 2 and 30x70 µm2 ).

Fig. 2 Electrogenic cell on G-SGFET during patch clamp.

Fig. 3. Average of 83 consecutive action potentials of a electrogenic cell recorded by G-SGFET.

Size dependence effects of Aluminium oxide nanoparticles on red blood cells Vinardell MP, Sordé A, Mitjans M Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain mpvinardellmh@ub.edu

Abstract The interaction of nanomaterials (NMs) with cell membranes is an important research area because it is critical in many applications [1] and the effects of NMs on cell membranes are worth attention for both their applications and safety assessments. Aluminium oxide NMs are the most abundantly produced and used in diverse fields such as medical, military and industrial purposes [2]. Examining the influence of shape and size of NMs on cell interactions is crucial as these can have implications in toxicity [3]. The haemolysis assay is recommended as a reliable test for material biocompatibility [4]. Particle size and surface are key factors that affect haemolysis. In the case of silver nanoparticles, it was observed that a distinct increase in the haemolytic properties of nano-sized particles compared to the micron-sized particles at equivalent mass concentration [5]. In this work we have studied the effect of three different commercial nano-sized aluminium oxides on red blood cells, compared to the micro-sized aluminium oxide. The method used was the haemolysis assay as described in previous papers [6] and adapted to the study of NMs. Briefly, red blood cells obtained by centrifugation from fresh blood were incubated at 37ºC and at room temperature for 24 hours with different concentrations of the different types of aluminium oxide. At the end of the incubation period, tubes were centrifuged and the amount of haemoglobin on the supernatant has been determined by spectroscopy at 540 nm to determine the percentage of haemolysis induced by the chemicals, compared to blood totally haemolysed. We have used red blood cells from human, rat and rabbit, showing a different behaviour. Red blood cells from rabbits were more affected by the nano-sized aluminium oxide than human or rat red blood cells. By contracts, similar results were observed for micro-sized aluminium oxide in the three species (Figure 1) The addition of albumin induced a significant reduction on the haemolytic effect of the nano-sized aluminium oxide expressed by an increase in the HC 50 (concentration that induces 50% of haemolysis), compared to the micro-sized one which presents no effect (Figure 2). Another factor to be into account when comparing studies of haemolysis is the temperature of incubation. The hemolytic activity of the nanoparticles increased with temperature in line with other studies performed with silica particles [7]. Interestingly, the temperature dependence of hemolysis varied among the aluminum oxide nanoparticles. In conclusion, size and shape of aluminium oxide nanoparticles influence the interaction with cell membrane. These results should be taken into account when synthesizing new nanomaterials more safe with less effect on health. References [1] Verma A, Stellaci F, Small 6 (2010) 12. [2] Balasubramanyam A, Sailaja N, Mahboob M, Rahman MF, Hussain SM, Grover P, Toxicology in Vitro 24 (2010) 1871. [3] Nel E, Madler L, Velegol D, Xia T, Hoek EMV, Somasundaran P, Klaessig F, Castranova V, Thompson M, Nature Materials 8 (2009) 543. [4] Lu S, Duffin R, Poland C, Daly P, Murphy F, Drost E, Macnee W, Stone V, Donaldson K. Environmental Health Perspectives 117 (2009) 241. [5] Choi J, Reipa V, Hitchins VM, Goering PL, Malinauskas RA. Toxicological Sciences 123 (2011)

133. [6] Nogueira DR, Mitjans M, Infante MR, Vinardell MP. Acta Biomaterialia 7 (2011) 2846. [7] Shi J, Hedberg Y, Lundin M, Odnevall Wallinder I, Karlsson HL, Möller L. Acta Biomaterialia 8 (2012) 3478

Figures .

Figure 1. Behaviour of human, rabbit and rat erythrocytes in front of different aluminium oxide nanoparticles and macroscopic aluminium oxide ( human, rabbit, rat)

Figure 2. Effect of albumin addition on the haemolysis induced by different Al2O3 nano forms and micro-sized Al2O3 on rabbit red blood cells.

Near-Field Mid-Infrared Photocurrent in Graphene 1

Achim Woessner, Mark B. Lundeberg, Pablo Alonso-González, Qiong Ma, Ivan Nikitskiy, 3 2,4 1 Pablo Jarillo-Herrero, Rainer Hillenbrand and Frank H.L. Koppens 1

ICFO ± The Insititute of Photonic Sciences, 08860 Castelldefels (Barcelona), Spain 2 CIC nanoGUNE Consolider, 20018 Donostia-San Sebastián, Spain 3 Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4 IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain E-mail: achim.woessner@icfo.es, frank.koppens@icfo.es Abstract Light detectors that operate in the mid-infrared spectrum are of potential interest for detection of molecular resonances and thermal imaging. The conventional photodetectors in this range however require significant cooling or exhibit low sensitivity. Due to the broadband absorption of light in graphene, it is a promising material for sensitive mid-infrared photodetectors at room temperature. [1] In order to understand the large scale device physics of such detectors it is important to also understand how photocurrent is generated at defects, such as wrinkles or grain boundaries and what influence they have on the large scale photodetector behavior. Our study investigates light-driven electrical photocurrents in graphene for the mid-infrared range of incident light. Using a scattering-type scanning near-field optical microscope [2] we manage to couple the light very locally into the graphene and therefore reach an extremely high resolution of the photocurrent. As the light absorption in this case causes mainly a local heating effect, the current can be understood in terms of thermoelectric effects. [3] We investigate the influence of local defects, such as grain boundaries [4] and bilayer spots in CVD graphene as well as charge puddles in exfoliated graphene [5] on photocurrent. We determine how carrier density influences these effects and show that the results can be nicely explained using a thermoelectric model. We show an unprecedented high resolution of the photocurrent and demonstrate that this technique can be used for the local characterization of graphene devices.

References [1] Q. Bao and K. P. Loh, ACS Nano 6, 3677 (2012). [2] N. Ocelic, A. Huber and R. Hillenbrand, Applied Physics Letters 89 (2006). [3] P. K. Herring, et al., Nano Letters 14, 901±907 (2014). [4] Z. Fei et al., Nature Nanotechnlogy 8 (2013). [5] J. Martin et al., Nature Physics 4 (2007).

Pulsed laser depositon of biaxially textured SrTiO3 buffer layer on cube textured Cu-based substrate J. A. Padilla1, E. Xuriguera1,2, L. Rodríguez3, A. Vannozzi4, G. Celentano4 1

IN2UB, Diopma, Materials Science and Metallurgical Engineering Department., Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain 2 La Farga Lacambra SAU, Ctra. C17z Km. 73,5, 08508 Les Masies de Voltregà, Barcelona, Spain 3 Departament de Física Aplicada i Òptica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain 4 Supercondutivity Laboratory, ENEA FrascatiResearch Centre, Via Enrico Fermi 45, I-00044 Frascati, Roma, Italy xuriguera@ub.edu Abstract Strontium titanate (STO) is of great of interest to use as buffer layer for growing perovskite thin films, since their lattice constant is closely matched to a large number of other perovskite oxides [1]. Biaxially textured STO buffer layer has been grown by pulsed laser deposition (PLD) [2] on rolling assisted biaxially textured substrates (RABiTS) made of low cost Cu-clad stainless steel substrate (by Tanaka [3]), which presents a strong cube texture. This study presents the optimization of PLD process to grow the hightly textured (00l) STO films on metallic substrates using reducing atmosphere (Ar/5%H2) to prevent the oxidation of the substrate. STO was deposited by PLD using 248 nm radiation of the excimer laser KrF at different temperatures -5 from 850 to 300ºC. The chamber was evacuated to a base pressure of 1x10 mbar and then was refilled -4 with Ar/5%H2 to a pressure of 4-6x10 mbar. The repetition rate and laser fluence were controlled at 2 10Hz and 1,5-2J/cm , respectively. The target-to-substrate distance ranged from 40 to 50mm and the STO films were typically deposited to reach a thickness in the range 200±300 nm. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and electron backscattering diffraction (EBSD). XRD analyses reveal that between 850º and 700ºC, the samples present random orientation or two main orientations. However, the samples exhibit strong cube texture from 600 to 300ºC. X-Ray -scans and -scans of the samples were performed to evaluate the quality of texture, rocking curves around rolling direction (RD) and transverse direction (TD) of (002) peak of STO and -scan at =54,74º of (111)STO respectively. STO film deposited at 500ºC exhibits the best quality texture with an excellent repeatability. The full width at half maximum (FWHM) of -scans RD and TD of (002) STO and -scan (111) STO were 5º, 7.1º and 6.1º, respectively (Figure1). AFM analyses on STO film show a morphology composed of rounded grains with a height around 10 nm (Figure 2). Rms roughness measured is 2.5-3.5 nm. SEM images reveal an adequate two dimensional growth of the layer and a smooth and uniform surface. EBSD analyses are in line with XRD measurements and show that STO film grows epitaxially. (Figure 3), with >97% of cube texture with 12º tolerance angle. STO/Cu-clad stainless steel architecture prepared by this technique may provide useful templates for the growth of perovskites such as YBa2Cu3O7-X coated conductors and ferroelectrics thin films. References [1] B. M. Kim et al., Appl. Phys. Lett. 84 (2004) 1946 [2] J. Chen et al., Jpn. J. Appl. Phys. 43 9A (2004) 6040 [3] N. Kashima et al., Jpn. J. Appl. Phys. 50 (2011) 063101

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Figure 3. a) EBSD map of STO and b) (111) pole figure of STO obtained from EBSD measurement. The rolling direction is vertical. In the EBSD map, red, green and blue refer to (100), (110) and (111) orientation, respectively.

Flexible reduced graphene oxide gas sensor deposited by electrospray 1,2,3

E. Xuriguera

, O. Monereo , A. Varea , A. Cirera

1 1

MIND/IN2UB, Electronics Department, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain 2 IN2UB, Diopma, Materials Science and Metallurgical Engineering Department., Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain 3 DIOPMA S.L., Baldiri i Reixac 1, 08028 Barcelona, Spain xuriguera@ub.edu

Abstract In the last decade, flexible gas sensors are a great of interest because of its inherent characteristics such as adaptability and conformability. If these properties are combined with integration of graphenebased material onto these device and low-cost fabrication techniques, like inkjet printing and electrospray, a new generation of sensors with a wide range of applications can be produced. Inkjet printing technique is one of the most used techniques for flexible electronic printing which really cover the gap between standard thick film and thin film technology [1]. On the other hand, graphene solutions can be used to deposit the material onto a desired substrate and electrospray technique can work under room temperature and ambient pressure, i.e. it does not require vacuum and high temperature equipment, it is scalable, and a wide variety of substrates can be used. The aim of this work is to present the deposition of carbon-based compounds such as reduced graphene oxide (rGO) film by means of electrospray and show the gas sensing properties of the film. Interdigitated electrodes and heater resistance, in the backside, were inkjet printed on flexible polyamide film using silver ink. The rGO was dispersed in isopropanol and electrosprayed over silver interdigitated electrodes with a mask to delimit the deposition area (Figure 1). Structural and morphological properties of the deposits are correlated with the electrospray parameters. Also, it demonstrated that electrospray is a feasible and reliable technique to deposit small- and largeareas of rGO with a good thickness control and spatial resolution. In order to study the response of the sensors to humidity, two gas tests were performed. The first test consists of twelve pulses with duration of half hour, all of them with a concentration of 50% of relative humidity at room temperature. This sequence allowed us to check detection capacity and study the repeatability and stability of the signal. Figure 2 shows a typical dynamic response of a conductometric gas sensor device [2]. The rGO sensor detects water vapor with a signal drift. Furthermore, all the pulses have an excellent repeatability, except the first one. In the second test, pulses of relative humidity with different concentration were applied to the device, consisting of four pulses of increasing concentration from 25 to 100% followed by two pulses of 50%. The test was repeated at different operation temperatures. As it can be observed, Figure 3 displays that low temperature, close to room temperature, is enough to achieve a suitable stability and a good sensing response. In conclusion, low-cost flexible humidity sensors based on rGO can be produced using cost-effective techniques such as inkjet printing and electrospray. References [1] P. G. Su et al, Sens. Actuators B 139 (2009) 488 [2] G. Lu et al, Nanotechnology 20 (2009) 445502

Figures

Figure 1. View of four sensor array in top side with the deposit of rGO and heater in the backside

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Graphite/ZnO nanorods junction for ultraviolet photodetectors Roman Yatskiv, Maria Verde, Jan Grym Institute of Photonics and Electronics, Chaberska 57, Prague, Czech Republic yatskiv@ufe.cz

Abstract Zinc oxide is a well-known material which has been widely used for optoelectronic applications, due to its direct wide bandgap (Eg 3.3 eV at 300 K), large exciton binding energy (~60 meV), good optical transmittance in the visible region (90%), high optical gain (about three times higher than GaN), and efficient radiative recombination [1]. Moreover, in recent years there has been an increasing interest on ZnO nanostructures for their use as UV photodetectors [2-5]. Here we report a new kind of graphite/ZnO NRs junction photodetector for UV sensing. The graphite/ZnO NRs junctions were prepared by hydrothermal growth and deposition of colloidal graphite. The electrical properties of these junctions were investigated at different temperatures (Fig.1c). It was found that their I-V characteristics can be well described by a tunnel-recombination current transport mechanism via interface states (more information about the preparation of the junctions and a detailed analysis of the transport mechanism were reported in our previous work [6]). The IV characteristics of the graphite/ZnO NR junctions measured in dark and under UV illumination are presented in Fig. 2. Both reverse and forward currents increased due to the absorption of UV light, which generated electron-pair holes in the depletion region. Due to the built-in electric field of the depletion region, the holes move towards the anode and the electrons move towards the cathode, thus generating photocurrent. Fig. 3 shows the photocurrent response (of the graphite/ZnO NR junctions) at zero bias voltage. These structures show very fast response times and good reproducibility. This work was supported by a EU COST Action TD1105 â&#x20AC;&#x201C; project LD14111 of the Ministry of Education CR. References [1] Ozgur, U., et al., J Appl Phys (2005) 98 (4) [2] Hatch, S. M., et al., Advanced Materials (2013) 25 (6), 867 [3] Hassan, J. J., et al., Appl Phys Lett (2012) 101 (26) [4] Nie, B. A., et al., Small (2013) 9 (17), 2872 [5] Bai, S., et al., Adv Funct Mater (2011) 21 (23), 4464 [6] Yatskiv, R., et al., Carbon (2014) 77, 1011

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Synthesis of High Surface Area Titania Based Nanoparticles and the Effect of Surfactants Alp Yurum1, Miad Yarali2, Selmiye Alkan Gürsel2 1

Sabanci University Nanotechnology Research and Application Center, Tuzla, Istanbul 34956, Turkey 2 Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla, Istanbul 34956, Turkey ayurum@sabanciuniv.edu

Abstract In this study, TiO 2 based nanotubes and nanosheets were synthesized to be used as an adsorbent and support in various processes. As a starting material, sol-gel synthesized anatase and commercial anatase were used. TiO 2 was converted to high surface area hydrogen titanate (H 2 Ti 3 O 7 ) and sodium titanate (Na 2 Ti 3 O 7 ) nanotubes and nanosheets under alkaline conditions with hydrothermal treatment. In addition, synthesized materials were modified with surfactants (dodecyl amine, cetyl trimethylammonium bromide) to enhance the surface properties. XRD, TGA, SEM, and BET analyses were utilized to characterize the materials. The results suggest that synthesized materials with their high surface areas and active surfaces are promising materials for energy and water treatment areas. Introduction The nanostructured TiO 2 materials other than anatase structure having layered structure are alkali titanates (A 2 Ti n O 2n+1 ), protonic titanate (H 2 Ti 3 O 7 ), and lepidocratic species. The unique mesoporous, high surface area properties of these materials offer promising results as semiconductors, catalytic materials and adsorbents [1]. The synthesis of alkali titanates with wet methods is possible with both a solid-state reaction by treating TiO 2 with alkali carbonate-peroxide mixtures [2] and hydrothermal treatment with strong basic solutions [3]. In the present study, synthesis of mesoporous titanate species, which were produced from commercial anatase (COM), and synthetic TiO 2 produced by sol–gel technique (SG) were studied. The effect of hydrothermal synthesis conditions on the structure was also examined. Experimental For the synthesis of SG, titanium tetraisopropoxide was used as a precursor. After obtaining the gel, samples were calcined at various temperatures to optimize the surface properties. After that step, SG and COM were treated with 10 M NaOH solutions at various temperatures and durations to see the effect experimental parameters on the structure of titanates. Finally, after hydrothermal treatment, samples were washed with either DI water or HCl solution to obtain Na 2 Ti 3 O 7 or H 2 Ti 3 O 7 respectively. As an additional step, surfactants were added before starting the hydrothermal treatment. At every step, the structural characterization of the samples were done using SEM, TGA, XRD, and BET techniques. Results & Discussions XRD characterization of COM and SG revealed that both of the samples are pure anatase. However, it can clearly be seen that the crystallinity is higher for COM sample when compared with SG version. The peaks show that SG samples have smaller crystallite size. The XRD patterns also show that with increasing calcination temperatures, crystallite sizes start to increase. SEM images reveal that while the size of SG particles is about 10 nm, the size of COM particles is around 200 nm. After hydrothermal treatment, both the morphology and crystal structure of the samples changed. After 24 hours of treatment, titanate structures started to appear but XRD patterns show that there is still anatase phase available in the structure. However, after 48 hours of treatment, the samples are completely of titanate structure (Figure 1). Interestingly, SG and COM yielded different morphologies. While COM samples after 24 hours of hydrothermal treatment transformed to nanotubes, SG samples transformed to nanosheets. At the end of 48 hour of treatment, the SG particles finally transformed to nanotubes. The nanotubes obtained have a diameter of 30 nm and similarly the thickness of the plates is about 30 nm (Figure 2). After the hydrothermal treatment, washing the sample with HCl solution had a significant effect on the crystal structure. The peak around 10° corresponds to (200) and it is related to the distance between the titanate layers. With acid washing, the layers expanded. Also synthesizing titanates in the presence of surfactants affected the structure of particles. While nanotubes were obtained, these nanotubes had a diameter of 40 nm. These nanotubes entangled to each other forming sheets and these sheets were stacked on each other.

The specific surface areas of SG and COM are 66 and 40 m2/g respectively. After hydrothermal treatment, the surfaces areas obtained ranges from 141 to 169 m2/g. This increase in surface area is due to the layered structure of titanates. Pore size distribution (PSD) curve of the sample treated for 48 hours reveal a very sharp peak at 9.9 Å (Figure 3). This is the interlayer distance of titanates obtained. This distance increases with acid washing. Addition of the surfactants increases this distance further to 12.5 Å. Thanks to this expansion, atoms can easily enter and leave the structure. By exfoliating the titanate layers, more surfaces can be exposed and these materials can be used in areas like energy and water treatment. Conclusion Nanostructured mesoporous titanate samples were synthesized with hydrothermal treatment under alkaline conditions from commercial and sol–gel synthesized anatase. Both the commercial and sol–gel derivative with their mesoporous structure possess high surface areas with expanded layers. As a future study the exfoliated titanates will be used either as a support material or adsorbent for water remediation processes. References [1] B. K. Erdural, A. Yurum, U. Bakir, G. Karakas, J. Nanosci. Nanotechnol., 8 (2008) 878. [2] M. Watanabe, J. Solid State Chem., 36 (1981) 91. [3] M. Tomiha, N. Masaki, S. Uchida, T. Sato, J. Mater. Sci., 37 (2002) 2341. Figures

Figure 1. XRD patterns of hydrothermally treated commercial anatase

Figure 2. SEM images of hydrothermally treated commercial anatase

Figure 3. Pore size distribution curves of hydrothermally treated commercial anatase

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International Conference & Exhibition

800 participants 85 exhibitors represented 357 posters 150 speakers 53 grants & 12 awards

March 10-13 Bilbao (Spain)

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