CPV developer Soitec, along with German research body Fraunhofer ISE and Frances CEA-Leti, has announced a new conversion efficiency record for a multi-junction PV cell. The cell is based on III-V semiconductor material, with the efficiency record achieved by using Fresnel lens concentration of 508 suns. The record has been confirmed by Japans Advanced Industrial Science and Technology (AIST).
Soitec and its research partners reports that one of the challenges to be overcome was to ensure that the photons are distributed exactly among four sub-cells. This was achieved by precise tuning of each semiconductor layer.
Jocelyne Wasselin, vice president of solar cell product development for Soitec said that using the four-cell approach, would allow the company and its research partners to achieve a 50% efficient cell, in the near future.
"We are very proud of this new world record. It confirms we made the right technology choice when we decided to develop this four-junction solar cell, said Soitecs Wasselin. To produce this new generation of solar cells, we have already installed a line in France. It uses our bonding and layer-transfer technologies and already employs more than 25 engineers and technicians.
Soitec operates three fabs to produce the cells the concentrator technology it employs. Its primary manufacturing location is in Bernin, France. It also has a production facility for its Concentrix concentrator technology in San Diego.
This is a major milestone for our French-German collaboration, said Fraunhofer ISEs Frank Dimroth "CPV is the most efficient solar technology today and suitable for all countries with high direct normal irradiance."
Figure1: IV characteristics of the new 4-junction solar cell with an efficiency of 46% at 50.8 W/cm2 which corresponds to a concentration ration of 508 times the solar AM1.5d (ASTM E927-10) spectrum.
Soitec collaborated with Fraunhofer ISE, CEA-Leti and Helmhotz Center Berlin on its previous record, which registered a conversion efficiency of 44.7%, employing concentration of 297 suns.