Scientists from Fraunhofer ISE and the FMF of the University of Freiburg could improve on the record for a 1 square centimetre organic solar cell announced in September 2020. With an efficiency of 15.8 percent, the new solar cell once again sets the world record in this category.
"We achieved the improvement in the record solar cell quite significantly by using an anti-reflective coating," explains Uli Würfel. He is head of the department for organic and perovskite photovoltaics at Fraunhofer ISE.
Semi-transparent cells in the works
This way, more light is absorbed in the photoactive layer of the cell - and a higher current is generated. The thin-film system required for the coating was developed by researchers in a neighbouring department at Fraunhofer ISE.
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In addition to reducing surface reflection, Fraunhofer ISE is also developing electrodes for semi-transparent organic solar cells with this coating process. These consist of a photoactive organic layer applied to a back electrode, which transmits the visible light and simultaneously reflects the near-infrared light back into the cell.
Advantages of organic solar cells
Organic solar cells, or OPVs, can be manufactured without the use of heavy metals and other critical elements. They have a low weight, are mechanically flexible and can be integrated very well. In addition, they have a homogeneous appearance even when semi-transparent.
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By selecting organic semiconductors that absorb only infrared light, it is possible to develop transparent solar cells for windows and agricultural protection films or greenhouse glass that can combine various benefits such as protection against bad weather and overheating with relevant electricity generation. However, there are still some development steps to be taken before the product is ready. (nhp/mfo)
