39.7% solar cell efficiency
FREIBURG, GERMANY, October 6, 2008. A 39.7% efficiency for a multi-junction solar cell has been reached by researchers at the Fraunhofer Institute for Solar Energy Systems ISE.
This exceeds the institute’s own European record of 37.6%, which was achieved recently.
“We have improved the contact structures of our solar cells,” says Frank Dimroth, Head of the III-V – Epitaxy and Solar Cells Group at Fraunhofer ISE. “As a result, using the same semiconductor structures, we now achieve the higher efficiency when converting sunlight into electricity.”
III-V semiconductor multi-junction solar cells are used in photovoltaic (PV) concentrator technology for solar power stations.
For the last two years, work has been carried out on a new programme for the theoretical calculation of optimal contact structures at Fraunhofer ISE, and the newest record was achieved due to this work, which has been sponsored by the EU Project Fullspectrum (SES6-CT-2003-502620).
The cells are especially suitable for inhomogeneous radiation, which occurs in the case of concentrated sunlight, and have been installed in the concentrator modules of the type FLATCON® at Fraunhofer ISE and at the spin-off company Concentrix Solar GmbH, among others.
“We are very pleased to have advanced a further decisive step in such a short amount of time,” says Dr. Andreas Bett, Department Head at Fraunhofer ISE. “Highest conversion efficiencies help the young technology to become market competitive and to further sink the costs of generating electricity from the sun for the future.”
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