NREL, CSEM and EPFL are working with what are known as ‘multi-junction’ cells, a technology that combines silicon with a cell that absorbs blue light from the sun more efficiently.
The transition from a silicon single-junction cell to a silicon-based multi-junction solar cell has the potential to push efficiencies past 30% while still benefiting from the cost-effective manufacturing expertise in making silicon solar cells. NREL and Swiss scientists have devoted themselves to producing such solar cells with over 30% efficiency. In January 2016, this researcher’s team was able to reach 29.8% efficiency, setting their first joint world record.
By working together again, the scientists team from CSEM, a Swiss research and technology center, EPFL, and NREL, have beaten their own record and cemented their positions as the top experts in this technology: an efficiency of 32.8 % was achieved for a dual-junction solar cell made by combining NREL GaAs top cell to CSEM silicon heterojunction bottom cell, and an efficiency of 35.9 % was attained for a triple-junction solar cell by combining NREL GaInP/GaAs top cell to CSEM silicon heterojunction bottom cell.
“These records show that combining crystalline silicon and other materials is the way forward if we are to improve solar power’s cost/efficiency ratio,” said Christophe Ballif, Director of CSEM’s PV-center and EPFL Photovoltaics laboratory. “It affirms that silicon heterojunction solar cells, when integrated into the structure that we’ve developed, can generate multi-junction cell conversion efficiencies over 32%” said Matthieu Despeisse, manager of crystalline silicon solar cells activities at CSEM.
Source: https://www.nrel.gov or https://www.csem.ch/home