7 May 2010


Fraunhofer ISE’s Frank Dimroth receives French science prize

Dr Frank Dimroth of the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany is to receive the ‘Fondation Louis D’ award (the highest-endowed award presented in France for achievements in science). The prize carries a cash value of 750,000 euros, and will be presented on 9 June at the Institut de France in Paris.

The Fondation Louis D was established 10 years ago under the auspices of the Institut de France (a non-profit organization dedicated to the advancement of language, science and the arts), and presents a major science award each year (along with a major award for research in the humanitarian or cultural area).

Dimroth and his team have developed a metamorphic triple-junction solar cell which can reach a record solar energy conversion efficiency of 41.1% (nearly double the efficiency of conventional silicon-based solar cells). To accomplish this, the researchers fabricated a multi-junction solar cell made of III-V compound semiconductors through MOCVD deposition of three single-junction sub-cells on top of each other (on a germanium substrate), each one being particularly efficient in converting a limited spectral bandwidth of sunlight to electricity.

Hence, with the development of metamorphic crystal growth, Dimroth and his colleagues can use a larger range of III-V compound semiconductors to grow multi-junction solar cells, making the solar cells better adapted to the spectrum of wavelengths found in sunlight.

To achieve high efficiency, Dimroth’s team developed a concentrating photovoltaic (CPV) module that uses Fresnel lenses to concentrate solar radiation by a factor of 500 onto triple-junction solar cells just 3 mm2 in area. This reduces the costly semiconductor surface area required and makes III-V multi-junction solar cells for electricity generation an attractive alternative in regions rich in direct sunlight, Fraunhofer ISE says.

“We expect that high-efficiency concentrator technology - in addition to photovoltaics using crystalline silicon and the classic thin-layer technology - will become established as a third technology for cost-efficient generation of solar electricity in the sunny regions of the world,” comments Fraunhofer ISE’s director Professor Eicke R. Weber.

“Concentrator systems have the potential to supply Southern Europe with low-cost solar electricity in a matter of just a few years,” concludes Dimroth.

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