Nanowire as solar cell

Published: Friday 30 November 2007

a new nanowire promises to revolutionalize the world of nanotechnology. Developed by scientists at Harvard University, the wire, which is a fraction of the width of human hair, will function as a solar cell, generating power for its own use, and other nanodevices.

Scientists say the nanowire is more efficient than solar devices but not enough for large-scale power generation yet. Unlike older nanoscale solar cells made of a combination of organic and inorganic materials, the new solar cell is purely inorganic--it is made of silicon. The nanowire looks like a tv cable, having three concentric layers of silicon. The outermost layer has an excess of electrons that are released when light falls on it thereby generating electricity. The scientists say that the combination of silicon and the nanowire's geometry increases its efficiency and lowers degradation on use.

The nanowire converts 3.4 per cent of the incident light into electricity at present. For conventional silicon solar panels, the figure is more than 20 per cent. Charles Lieber, the lead researcher, says the efficiency needs to be improved for large-scale power generation, until then the cost could not be estimated. He said the cost depends on further research.

The study was published in the October 18 issue of Nature.

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