King Abdullah University of Science and Technology
BEACON املنـارة at Thuwal, Kingdom of Saudi Arabia
June 2013 / Shaban 1434 Volume 3, Issue No. 10
the
www.kaust.edu.sa
(L-R) PhD student Alfonso Caraveo-Frescas, Dr. Hala Al-Jawhari, a visiting assistant professor from King Abdulaziz University, Professor Husam Alshareef, and postdoctoral fellow Dr. Pradipta Nayak examine a p-type oxide thin film transistor fabricated in the lab.
A well-designed nanostructure that combines the plasmonic and catalytic activities in the form of a single crystal enables the study of the kinetics of a catalytic reaction at the monomolecular layer scale with SERS
OBSERVING REAL-TIME CATALYTIC REACTIONS ON NANOMATERIALS RESEARCHERS at KAUST have demonstrated how even at ultra-small or nanometer-scale, well-designed nanomaterials can successfully integrate multiple functions for delicate and important applications. In a paper recently published in the Journal of the American Chemical Society, Professor Yu Han and his team from the Advanced Membranes and
KAUST/KING ABDULAZIZ UNIVERSITY COLLABORATION SETS PERFORMANCE RECORD IN TRANSPARENT ELECTRONICS
Porous Materials Center outline how they have developed an efficient platform for investi-
“SnO, or tin monoxide, is a very elusive and challenging material to
gating the kinetics of catalytic reactions with
work with,” notes Alfonso Caraveo-Frescas, a PhD student in Prof.
surface-enhanced Raman spectroscopy (SERS).
Husam Alshareef’s Functional Nanomaterials and Devices group in
The other authors are: Jianfeng Huang, Yihan
Materials Science and Engineering. Over the past year, Caraveo-Frescas
Zhu, Ming Lin, Qingxiao Wang, Lan Zhao,
and Dr. Hala Al-Jawhari, a visiting assistant professor from the Physics
Yang Yang, and Ke Xin Yao.
Department at King Abdulaziz University, have worked to tackle a
By using a wet-chemistry synthetic method,
difficult task involving the material — developing SnO as a viable
the scientists created an ideal catalyzing envi-
p-type transparent oxide semiconductor material, an advancement
ronment whereby highly active catalytic sites
which has the potential to produce a significant technological leap in
are united with strong SERS sites in a single
transparent electronics, display, and solar cell applications.
entity. Through the real-time data obtained
Caraveo-Frescas and his research collaborators’ work resulted in a
over this platform, the kinetics of the hydro-
paper published recently in the high-impact journal ACS Nano, which
genation reaction of 4-nitrothiophenol can
can be accessed at http://pubs.acs.org/doi/full/10.1021/nn400852r#.
be directly determined. The innovation of this
In semiconductors, current conduction occurs via free electrons and
research is through the in-situ and real-time
electron holes. In its pure state, a semiconducting material conducts
monitoring of catalytic reaction processes
little current and is of limited value. To increase conductivity, con- transparent oxides that transport electrons and holes equally fast, we
over heterogeneous catalyst surfaces with
ventional semiconductors are modified or “doped” with impurities to
high sensitivity. It is even possible to peer
increase the number of free electrons, which results in n-type semi- better resolution, and we could eliminate the need for backlights in dis-
down to the monomolecular level.
conductors, or holes, which results in p-type semiconductors.
A fabricated device produced by the researchers contains several hundred thin film transistors and uses gold for the electrodes to make it visible Adds Prof. Alshareef: “If we were able to make fast transistors using could make power-efficient transparent electronics and displays with plays, as these drain the battery of many portable devices.”
Conventional methods, such as the Fourier
Oxide semiconductors, which are used in thin-film transistors
Prof. Al-Jawhari and Caraveo-Frescas were assisted in their research
transform infrared spectroscopy, mass spec-
(TFTs), are unique because they can also be doped by controlling the
by KAUST postdoctoral fellow Dr. Pradipta Nayak, Prof. Alshareef,
troscopy, and gas chromatography suffer from
level of oxygen in the material, a process which must be carefully
and members of the research group of Dr. Udo Schwingenschlögl,
slow response, low sensitivity, or incapability
carried out under precisely controlled conditions to correctly tune the
KAUST Assistant Professor of Materials Science and Engineering. Prof.
to detect surface species. They therefore aren't
material’s electronic structure.
Schwingenschlögl’s group, including former student Danilo Granato, a
able to reveal surface reactions in a real-time
n-type oxide semiconductors have made impressive progress in
manner. Overcoming these limitations, Prof.
areas like display electronics, for example, and companies such as
recent graduate from the master’s degree program, performed electronic
Han and his team’s work has developed a
Samsung and Sharp use n-type oxide semiconductors to fabricate
“Working with the group has been one of the best experiences I have
bi-functional (plasmonic and catalytic) plat-
high-resolution display technologies. However, p-type transparent
had in my career,” Prof. Al-Jawhari notes. “I am sure this work will pio-
form, which allows in-situ and real-time
oxide semiconductors that perform comparably to n-type oxides
neer the field of p-type oxide TFTs.” Adds Caraveo-Frescas: “I am very
monitoring of a catalytic reaction with very
have been difficult to develop. “The development of a high perfor- grateful to Prof. Al-Jawhari for her valuable discussions, perseverance,
structure calculations to help explain the experimental results.
high sensitivity down to the monomolecular
mance p-type transparent oxide semiconductor would open the door
and optimism, and to the entire team for helping me better understand
layer level by means of surface enhancement
for the fabrication of a huge variety of transparent electronics,” notes
SnO. I hope that our findings in the field of transparent electronics will
Raman spectroscopy.
Caraveo-Frescas, “and that possibility is really exciting.”
improve our lifestyle and reduce our excessive energy consumption.”
REAL-TIME REACTION | Continued on p4
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