Fraunhofer ISE claims 25.9% efficiency for III-V tandem solar cell

• The brand-new outcomes mark an improvement on the institute's previous 24.3% efficiency record. The III-V tandem solar cell is directly grown on silicon.

Germany's Fraunhofer Institute for Solar Energy Systems ISE asserts to have actually achieved a 25.9% conversion efficiency price for a III-V tandem solar cell expanded straight on silicon.

This outcome marks an enhancement on the institute's previous 24.3% performance record.

" This was attained by replacing a solitary slim layer within the multi-junction cell," stated scientist Markus Feifel. "A careful analysis of our cells showed that this layer produced a possible obstacle for electrons moving with the crystal structure."

Silicon was made use of as an absorber for the infrared part of the range. Several micrometer-thin layers of III-V substance semiconductors were transferred in addition to the silicon layer. All of the cell's different absorbers are internally adjoined by added crystal layers.

The cell is a modified version of a 34.5%- efficient III-V solar cell that is manufactured through a process known as direct wafer bonding, where the III-V layers are first deposited on a light weight aluminum gallium arsenide (GaAs) substratum and then pressed together.

" This technology is really effective but likewise expensive," the scientists said. "For this factor, Fraunhofer ISE has been working for several years on even more straight production procedures in which the III-V layers are deposited, or expanded straight onto a silicon solar cell."

The expense of generating solar cells based upon substances of III-V element materials-- named according to the groups of the periodic table that they come from-- has actually restricted such tools to specific niche applications including drones and satellites, where low weight and high effectiveness are much more important issues than expenses, in relation to the power produced.