Solar cell developed with highest efficiency ever at 44.7%

Sep 25, 2013
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The teams behind the world's previous record-holding solar cell for efficiency, which was unveiled back in May, has trumped its own achievement, announcing that they've boosted that cell's efficiency even higher to 44.7-percent. The latest solar cell works by utilizing four solar subcells, allowing it to achieve nearly a 50-percent efficiency rate, and was developed based on a bit over three years' worth of research.

The work was done by German and French teams from the Fraunhofer Institute for Solar Energy Systems ISE, Soitec, Helmholtz Center Berlin, and CEA-Leti. The technology utilizes concentrator photovoltaics, more commonly referred to as CPV, which is said to offer more than double the efficiency provided by the average photovoltaics used in sunny regions.

The higher efficiency is based on technology that was originally used with space-oriented works, with III-V multi-junction solar cells being constructed from different materials and oriented in a stacked manner upon each other to form a single subcell. Because of this method, various solar spectrum wavelength ranges can be absorbed by the subcell, resulting in a higher level of power being generated.

Frank Dimroth, Department Head and Project Leader at Fraunhofer ISE, said: "We are incredibly proud of our team which has been working now for three years on this four-junction solar cell. This four-junction solar cell contains our collected expertise in this area over many years ... 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."

SOURCE: Science Daily


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