Researchers have been since quite a while trying to increase the efficiency of solar modules, yet not more than 20% had been achieved.A new 2.4 USD million dollar project, funded by the U.S. Advanced Research Projects Agency for Energy plans to change this by increasing the efficiency to 50%. Apparently this will increase the output and reduce the number of panels required.
Professor Harry Atwater, Caltech University intends to use structured materials to sunlight into 8 to 10 different colors and direct them to semi-conductor that are perfect match with the color. This will result in improved efficiency as more of solar spectrum will be taken up which will cause more of the sunlight being converted into electricity rather than waste energy as heat.
This cognition isn’t a new one. One way ,which is an expensive one involves cultivating multiple semiconductor materials in a stack. Light will pass through the stack until it is absorbed by a semi-conductor which will efficiently convert it. It results in 43% efficiency, but the power output is hindered by the worst performing layer. Many other attempts have been made to sort out light using lenses, mirrors but have resulted in bulky products which are inefficient.
Few years back, it was difficult to split light into different colors on the same device. However, these days scientists have become more adroit and have been able to sort by color, trap it and guide from one position to another via thin layers of materials at a small scale level. These developments will play a significant role in this project and plans build on it. One layer will split light up, sort it by color, and then deliver it to a second layer that contains an cluster of solar cells matched to each color.
It will be tough to use this concept on a large scale level, but Atwater takes inspiration from development of television ( which runs on same concept of manipulating light through plethora of transistors), which were earlier full of defects and expensive. The materials required for this project are being developed in the market, but will remain expensive as long as production is low.Source- MIT Technology Review