Friday, April 19, 2013

The Solar Cell That Turns 1 Photon into 2 Electrons

The Solar Cell That Turns 1 Photon into 2 Electrons:
Solar cells are picky. If an incoming photon has too little energy, the cell won’t absorb it. If a photon has too much, the excess is wasted as heat. No matter what, a silicon solar cell can never generate more than one electron from a single photon. Such harsh quantum realities severely limit the conversion efficiency of photovoltaic cells, and scientists have spent decades looking for work-arounds.
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