Researchers At Stanford Discover New Solar Cells That Can Change The World
For Pete’s sake, please call on your state representatives and ask them to press for allocating some serious money in the development of PETE (photon enhanced thermionic emission) processing of solar cells, a technique developed by Stanford engineers. It has the potential to make the cost of large-scale solar cell power generation competitive with traditional methods of power generation.
The current photovoltaic technology only takes advantage of light from the sun, however, as temperature rises, the solar cells lose efficiency and the heat is wasted. The new process takes advantage of both light and heat from solar radiation and converts them to electricity, thereby tripling the efficiency of the existing solar cell technology.
In the PETE process the semiconducting material is coated with a thin layer of the metal cesium, which changes the characteristic of the cell, enabling it to use the previously wasted heat to generate electricity. In fact, the cells work better at higher temperatures. Most current generation silicon solar cells are inert by 100 C, while the new cells reach peak efficiency at well over 200 C.
Nick Melosh, an assistant professor of materials science and engineering, who led the research group at Stanford said, “It is actually something fundamentally different about how you can harvest energy.” He dubbed it as “a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak.” The materials needed to build the new solar energy converters are cheap and easily available, meaning that the power that comes from the device will be in the range of production cost of existing commercial plants.
According to Melosh’s calculation, the PETE process can reach efficiency up to 60 percent, which is three times as high as the efficiency of the existing systems. Regardless, with the experimental cells, the researchers never reached that efficiency, and they attributed that to the use of gallium nitride as their base semiconductor. The team believes that if they use gallium arsenide, which is employed in household electronics, they would reach the desired efficiency.
Continued on the next page
Follow Technorati