Researchers have developed a new coating that allows solar cells to cool themselves instead of requiring the use of coolants or ventilation, which can be water and energy intensive. Not only that, but the coating boosts power output and extends the life of the technology too.
By adding a specially patterned layer of silica glass to the surface of ordinary solar cells, a team of researchers led by Shanhui Fan, an electrical engineering professor at Stanford University in California has found a way to let solar cells cool themselves by shepherding away unwanted thermal radiation.
The researchers describe their innovative design in the premiere issue of The Optical Society’s new open-access journal Optica. This paves the way for developing high-efficiency, long-lasting solar cells. For every one-degree Celsius increase in temperature, the efficiency of a solar cell declines by about half a percent.
“That decline is very significant. The solar cell industry invests significant amounts of capital to generate improvements in efficiency,” informed Aaswath Raman, a postdoctoral scholar at Stanford University.
Solar cells are among the most promising and widely used renewable energy technologies on the market today. Though readily available and easily manufactured, even the best designs convert only a fraction of the energy they receive from the Sun into usable electricity.
The coating is made up of tiny pyramid and cone-shaped structures on a very thin layer of silica glass. The patterned glass redirects extra heat in the form or infrared radiation away from the cells.
“Silica is transparent to visible light, but it is also possible to fine-tune how it bends and refracts light of very specific wavelengths,” said Shanhui Fan, an electrical engineering professor at Stanford and lead researcher.
“A carefully designed layer of silica would not degrade the performance of the solar cell but it would enhance radiation at the predetermined thermal wavelengths to send the solar cell’s heat away more effectively.”
The researchers tested different shapes and sizes of cones and pyramids on silica compared to a flat layer of silica. They were able to fine tune the shapes to find the pattern that performed best. In testing, the patterned silica performed considerably better than the flat layer. The researchers are now working on outdoor tests of the technology. Read more about the story here.