A new way to harvest solar energy

A new and much more efficient way to convert solar energy into electricity has been discovered. The process is called Photon Enhanced Thermionic Emission(PETE). PETE could double or even triple the current efficiency of photovoltaic conversion by also taking advantage of the heat that usually goes to waste. Another plus is that PETE becomes more efficient at high temperatures while current photovoltaic technology becomes less efficient at increasing temperatures.

PETE is achieved by coating the photovoltaic semiconductor material with a thin layer of cesium. Research continues on which semiconductor materials work best for this process. PETE seems to work well at temperatures as high as 800C. The added efficiency over current photovoltaic materials could finally make solar price-competitive with oil. The new process uses already-existing and easily available materials and has been tested in southern California's Mojave Desert.

The research is being done by a joint venture of Stanford and SLAC National Accelerator Laboratory. The work is funded by the Defense Advanced Research Projects Agency and the Department of Energy. The original paper was published in Nature Materials after a success
ful demonstration of PETE.

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