Researchers achieve breakthrough for new solar power technology
The Sun
Credits:
"Lykaestria"
According to a March 20, 2013 story in SciTech, researchers at the Stanford Institute for Materials and Energy Sciences (SIMES) have achieved a breakthrough that increases the efficiency of an innovative solar energydevice 100 fold. The new device is based on a process called photon-enhanced thermionic emission (PETE), first demonstrated in 2010.
The efficiency was increased from a few 100s of a percent to two percent, but researchers are confident that another ten-fold increase is possible in the near future.
The way that a PETE device works is that it uses a special semiconductor chip to generate electricity from the entire spectrum of sunlight, including the part that generates heat. Standard photovoltaic cells use just a portion of the spectrum of sunlight to generate electricity.
If such devices can be produced cheaply enough on a mass scale, it has tremendous implications for solar energy production. The amount of electricity it generates actually increases the higher the temperature is. Such devices can be incorporated in the sorts of solar power stations that focus sunlight on a generator, such as a solar tower, to increase the amount of electricity by as much as 50 percent. It could generate far more electricity than conventional solar cells.
“The heart of the improved PETE chip is a sandwich of two semiconductor layers: One is optimized to absorb sunlight and create long-lived free electrons, while the other is designed to emit those electrons from the device so they can be collected as an electrical current. A cesium oxide coating on the second layer eases the electrons’ passage from the chip. Future research is aimed at making the device up to an additional 10 times more efficient by developing new coatings or surface treatments that will preserve the atomic arrangement of the second layer’s outer surface at the high temperatures it will encounter in the concentrating solar power plant.”
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