Researchers at the Fraunhofer Institute for Solar Energy Systems have tested a multi-junction solar cell that exhibited a 39.7% conversion efficiency ratio via photovoltaic concentrator technology.
‘We have improved the contact structures of our solar cells,’ says Frank Dimroth, head of the III-V/epitaxy and solar cells group at the Fraunhofer Institute. ‘As a result, using the same semiconductor structures, we now achieve the higher efficiency when converting sunlight into electricity.’
For utilization in photovoltaic concentrator systems, the optimal efficiency of multi-junction solar cells must often be achieved between 300 and 600 suns (at a sunlight concentration factor of 300 to 600).
The metallization of the front side makes the main difference for different concentration factors, the researchers say. In the front grid, the current is conducted through a network of thin wires from the middle of the solar cell to the edge, where it is then picked up by a 50-micrometer gold wire.
SOURCE: Fraunhofer Institute