Solar with 41-percent efficiency?

Researchers from the Freiburg, Germany-based Fraunhofer Institute for Solar Energy Systems say they've developed a solar cell with a record-breaking efficiency of 41.4 percent.

The institute is working with its spin-out Concentrix Solar and with Azur Space of Heilbronn, Germany, to commercialize the high-efficiency solar. 

The institute last announced an efficiency breakthrough in September, when researchers reached 39.7 percent efficiency for a III-V multi-junction crystalline silicon cell (see German solar reaches 40-percent efficiency). That broke their previous record of 37.6 percent achieved in March 2008.

The improvement in solar efficiencies is central in helping make solar more market competitive (see Striking up the intermediate band). 

The multi-junction solar cell reaching 41.4 percent efficiency was made using III-V-material on gallium-arsenide and germanium substrates. Researchers used amorphous multiple cells to avoid the formation of impurity traps that occur where materials overlap. 

The Fraunhofer researchers say they were able to concentrate the impurities in an electrically inactive area of the solar cell.

"This is a good example how the control over crystal defects within semiconducting materials can cause a technological breakthrough," institute manager Eicke Weber told the EE Times.

Light was concentrated on a 5-square-millimeter patch of the cell by a factor of 454.

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