Researchers from Northwestern University’s McCormick School of Engineering and Applied Science have developed a material that could one time revolutionize the solar cell industry, by absorbing a wider range of wavelengths than currently used materials are able to.
“The solar spectrum is not like a laser Ã¢â‚¬â€œ it’s very broadband, starting with UV and going up to near-infrared,” said Koray Aydin, assistant professor of electrical engineering and computer science and the paper’s lead author. “To capture this light most efficiently, a solar cell needs to have a broadband response. This design allows us to achieve that.”
Silver and silicon oxide have been used to create the thin, nanoscale metal gratings that they say can trap much more visible light. The combination is rather unusual; taken apart, these materials don’t absorb light, but together they literally “suck” light inside, transforming it into heat.
The fact is it’s the internal structure of the material that’s very important in the process, since the light resonates inside it just like it does when it reflects between two mirrors, thus having more time to get absorbed.
For the moment, the invention as it is cannot be used as a solar cell, because the silver/silicon oxide combination doesn’t transform light into electricity. However, future solar cells could replicate the trapezoid-like shape with semiconductors that can be turned into cheap photovoltaic elements.
Their invention has been described in a paper called “Broadband polarization-independent resonant light absorption using ultrathin plasmonic super absorbers.”