Silicon nanocrystal quantum effect found

U.S. Department of Energy scientists reported the discovery of a unique quantum physics effect in nanocrystals.

The researchers at the National Renewable Energy Laboratory, in collaboration with scientists at Innovalight Inc., discovered what they said is a new and important effect called Multiple Exciton Generation.

The effect occurs efficiently in silicon nanocrystals, resulting in the formation of more than one electron per absorbed photon, the scientists reported.

Until the new discovery, MEG had been reported during the past two years to occur only in nanocrystals -- also called quantum dots -- of semiconductor materials that are not presently used in commercial solar cells, and which contained environmentally harmful materials such as lead.

The new finding might lead to the application of MEG for greatly enhancing the conversion efficiency of solar cells based on silicon. That would represent a key step toward making solar energy more cost-competitive with conventional power sources, the researchers said.

The research is detailed in the on-line version of the American Chemical Society's Nano Letters Journal.

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