Washington, Sep 22 (IANS) Three engineers including one of Indian-origin from Stanford University have invented a novel transparent coating that cools solar cells to boost solar panel efficiency.
The invention shunts away the heat generated by a solar cell under sunlight and cools it in a way that allows it to convert more photons into electricity.
The discovery addresses a problem that has long bedevilled the solar industry: The hotter solar cells get, the less efficient they become at converting the photons in light into useful electricity.
The work by Shanhui Fan, professor of electrical engineering, research associate Aaswath P Raman and doctoral candidate Linxiao Zhu is based on a thin, patterned silica material laid on top of a traditional solar cell.
The material is transparent to the visible sunlight that powers solar cells but captures and emits thermal radiation, or heat, from infrared rays.
“Solar arrays must face the Sun to function even though that heat is detrimental to efficiency,” Fan said.
“Our thermal overlay allows sunlight to pass through, preserving or even enhancing sunlight absorption, but it also cools the cell by radiating the heat out and improving the cell efficiency,” he explained.
The new transparent thermal overlays work best in dry, clear environments, which are also preferred sites for large solar arrays.
They believe they can scale things up so commercial and industrial applications are feasible.
“That is not necessarily the only way. New techniques and machines for manufacturing these kinds of patterns will continue to advance. I am optimistic,” Raman noted.
In 2014, the same trio developed an ultra-thin material that radiated infrared heat directly back toward space without warming the atmosphere.
In the new work, the researchers applied that work to improve solar array performance when the sun is beating down.
The technology has significant potential for any outdoor device or system that demands cooling but requires the preservation of the visible spectrum of sunlight for either practical or aesthetic reasons.
The research was detailed in the journal Proceedings of the National Academy of Sciences.