Aug 29 (Renewables Now) - A new solar efficiency record of 35.9% for silicon-based triple-junction III–V/Si solar cells has been set by scientists at the US National Renewable Energy Laboratory (NREL) and Swiss research and technology institutes CSEM and EPFL.
The team used a top cell made of gallium indium phosphide and gallium arsenide (GalnP/GaAs), developed by NREL, in combination with a silicon-based bottom cell developed by CSEM based on the silicon heterojunction technology, NREL said on Friday.
The researchers also achieved a record of 32.8% for dual-junction III–V/Si solar cell made by combining NREL GaAs top cell to CSEM silicon heterojunction bottom cell. The previous record for a dual-junction III-V/Si solar cell was 29.8%, achieved by NREL and CSEM in January 2016.
"This achievement is significant because it shows, for the first time, that silicon-based tandem cells can provide efficiencies competing with more expensive multi-junction cells consisting entirely of III-V materials," said Adele Tamboli, senior researcher at NREL. The US research institute noted that the multi-junction cells technology combines silicon with a cell that absorbs blue light from the sun more efficiently and the transition from a silicon single-junction cell to a silicon-based multi-junction solar cell can boost efficiencies past 30%.