Fraunhofer ISE has achieved a 36.7% conversion efficiency with a concentrating photovoltaic (CPV) module, as measured under concentrator standard test conditions at a concentration of 230 suns. The components utilized are miniature versions of commercial CPV components, with a module aperture area of only 832 square centimeters.
The institute credits innovation at both the cell and module level for its accomplishment. The 7 square millimeter cells were the same with which Fraunhofer, Soitec, CEA-Leti and the Helmholz Center achieved a world record 44.7% efficiency in September 2013. These cells are based on a quadruple-junction design, with sub-cell layers of GaInP, GaAs, GaInAs and InP.
Soitec notes that its wafer bonding technology is a key component of this achievement, which allows it to link two semiconductor crystals, which otherwise could not be grown on top of each other with high quality.
These cells were incorporated into Fraunhofer’s FLATCON module concept, which utilizes 16 square centimeter Fresnel lenses manufactured by ORAFOL Fresnel Optics based on a new design by the institute. Fraunhofer ISE expects to successfully transfer this efficiency to commercial CPV module production within one or two years.