International Collaboration Leads to New and Improved Solar Panels

STEFAAN DE WOLF Associate Professor of Material Science and Engineering

BIFACIAL SILICON-ONLY SOLAR CELLS ARE RAPIDLY TAKING AN INCREASING SHARE OF THE PHOTOVOLTAICS MARKET… EXPLOITING THIS CONCEPT IN PEROVSKITESILICON TANDEMS OPENS OPPORTUNITIES FOR ULTRAHIGH POWER GENERATION AT AN AFFORDABLE COST.

Two-sided technology collects more energy to make solar more efficient and less expensive

ACWA POWER

“Bifacial photovoltaic installations are drastically driving down the cost of solar electricity generation. This technology is now rapidly taking a lead in the large-scale deployment of photovoltaics in the Kingdom. Combining bifaciality with emerging tandem technologies may further boost the performance of photovoltaic systems, which is a development of high interest to us.”

Doctor Engineer Bart Boesmans, Chief Technology Officer of ACWA Power

The global energy transition requires a combination of new and improved technologies to succeed. One of the biggest challenges of the shift to renewable sources, such as solar or wind, is to improve their performances so they can compete with their conventional counterparts.

KAUST researchers teamed up with colleagues from Canada’s University of Toronto, Italy’s University of Bologna and Germany’s Karlsruhe Institute of Technology to further progress the electricity generation of solar cells. Supported by the resources of the KAUST Solar Center, they discovered a new, more productive design for solar panels: they combined two solar cells in one tandem device, exploiting sunlight on both the front and rear sides instead of just the one side facing the sun. Writing for the January 2021 issue of Nature Energy, the team described a performance gain of at least 25% relative to conventional, single-sided panels made of silicon. Their tandem device uses a combination of crystalline silicon – the mainstream material for solar panels – and halide perovskite, a breakthrough semiconducting material with excellent optoelectronic properties. To the tandem configuration the researchers added the features of absorbing and converting indirect solar energy – light that has been reflected off a surface and scattered – from the rear side of the panel rather than relying only on direct incident sunlight. Indeed, light reflected off the ground behind the solar modules and scattered from adjacent structures can be efficiently harvested for electricity generation. The name bifacial – typical of this configuration – stems from the two-side absorption on the front and rear faces of the panel.

By combining the latest thinking in materials science and device engineering the team successfully fused two areas of developing research to achieve their breakthrough. Researchers have long been searching for alternative materials to those used in traditional panels made of silicon, and perovskite is emerging as a potential candidate. Progress has been reported on their power-conversion efficiencies, although challenges remain in wide-scale usage, including maintaining efficiency in large-scale facilities. When combined with silicon, tests have shown its potential to boost performance and cut manufacturing costs.