PHOTONS FOR BETTER SOLAR CELLS

Berkeley Scientists Focus On LED-Like Solar Cells

20 April 2012 (Solar Industry)

"New research from scientists at the University of California, Berkeley (UC Berkeley) has demonstrated that for maximum efficiency, solar cells might be designed to be similar to light-emitting devices (LEDs).

"…[T]he better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce…[Researchers] came across a solution [ to the large gap between the theoretical limit and the limit they have been able to achieve] based on a mathematical connection between absorption and emission of light."

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"Designing solar cells to emit light - so that photons do not become ‘lost’ within a cell - has the natural effect of increasing the voltage produced by the solar cell…

"PV manufacturer Alta Devices…has used the concept to create a prototype solar cell made of gallium arsenide (GaAs). The prototype broke efficiency records, according to UC Berkeley. The company achieved this milestone, in part, by designing the cell to allow light to escape as easily as possible from the cell…[E]fficiencies close to 30% may be possible in the coming years…"