SOLAR gain

There’s enough solar energy striking the earth every hour to meet the world’s energy needs for a year. The problem is capturing and storing it: current photovoltaic panels are only 15 to 20 percent efficient at best.

“Solar cells still are not cost effective for large-scale use,” said Richard Adams, a Carolina chemistry professor. “But if they were more efficient, large-scale applications would make more sense. There is a lot of solar energy, but it is fairly dilute—that’s why we need to improve the efficiency of solar cells.”

Adams and fellow chemistry professor Cathy Murphy are collaborating with a Wake Forest University physicist on a three-year, $810,000 grant sponsored by the Department of Energy, one of 27 funded by DOE that focus on solar energy research.

Murphy is developing silver and gold nano particles—shaped like tiny rods—that improve the absorption of visible light and amplify its effects. “You can tune the wavelength of light absorbed by changing the size of the nanorods,” Murphy said. “A single layer of these silver or gold nanorods in the solar cell is all that’s needed to get the improvement.”

Adams is developing metal sulfide nanoparticles that aid in creating photo-currents from the gathered solar energy. The nanoparticles will be loaded into solar cells and tested at the National Renewable Energy Laboratory in Golden, Colo.

“I think we have a good chance of making some improvements to the existing technology for solar cells,” Adams said. “If we can help improve their efficiency, we’ll have made a worthwhile contribution.”

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