Wednesday, 28 March 2012

Photovoltaic cells wiggle when lit

A surprising atomic-scale wiggle underlies the way a special class of materials reacts to light, according to research that may lead to new devices for harvesting solar energy.

For decades, scientists have known that some ferroelectric materials—materials that possess a stable electrical polarization switchable by an external electric field—are also photovoltaic: They produce an electric voltage when exposed to light, just as solar cells do. But it was not clear how the light induced voltages in these materials.

Such insight is very useful to researchers hoping to design ferroelectrics with improved photovoltaic properties for use in solar cells and other applications, such as sensors and ultrafast optical switches for data and telecommunications networks. Several possible mechanisms have been proposed, with many open questions still remaining.

The entire in-and-out atomic-scale wiggle took just 10 trillionths of a second, yet it indicated the mechanisms responsible for the materials’ photovoltaic effect. - caused by light-induced electrical currents in the ferroelectric material...

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