A new record was set by a cell structure
A solar cell structure with four sub-cells has set a new world record efficiency regarding solar sunlight conversion. The cell succeeded to set a new record efficiency hitting 44.7% and it is the creation of researchers from the Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin.
The German-French team from the mentioned associations made the announce of a a 43.6% efficiency for the german-french solar cell in this year’s May. But they managed to develop that groundwork and succeeded to expand the efficiency of the solar cell to 44.7%. This efficiency was measured at a concentration of 297 suns. This means that 44.7% of the solar spectrum’s energy, from ultraviolet through to the infrared, is transformed into electricity.
This four-junction solar cells have a utility in concentrated PV or CPV and are formed by several cells made out of different III-V semiconductor materials(composed of elements from III-V groups of the periodic table) one on top the other. The single sub-cells attract absorb different wavelength ranges of the solar spectrum.
“This four-junction solar cell contains our collected expertise in this area over many years. Besides improved materials and optimization of the structure, a new procedure called wafer bonding plays a central role. With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells,” as Frank Dimroth, Department Head and Project Leader in charge of the development work at Fraunhofer ISE describes the success.
Soitec’s CEO and Chairman André-Jacques Auberton-Hervé thinks that with the accomplishment of this record this four-junction solar cell design based on Soitec’s bonding techniques and expertise can actually be a part of the competitiveness of Soitec’s own CPV systems.
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