Researchers at University of California Riverside have created a coating for solar panels that could improve solar photovoltaic efficiency by 30 percent or more. “The infrared region of the solar spectrum passes right through the photovoltaic materials that make up today’s solar cells,” explained Christopher Bardeen, a professor of chemistry. “This is energy lost, no matter how good your solar cell.” The new coating developed by the team essentially reshapes the solar spectrum, allowing this energy to be captured and converted into electricity.
The bulk of the cost of solar technologies comes from the cost of installing the panels and the land used to house them. Solar cells themselves only make up about 20 percent of the cost of solar energy. Because of this, scientists have been working to improve the efficiency of the cells, so less land could be used to create solar power.
“The hybrid material we have come up with first captures two infrared photons that would normally pass right through a solar cell without being converted to electricity, then adds their energies together to make one higher energy photon,” Bardeen said. “This upconverted photon is readily absorbed by photovoltaic cells, generating electricity from light that normally would be wasted.”
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Upconverting two low-energy photons into one high-energy photon may have applications far beyond solar energy, Bardeen said. The technology could also be used in such technologies as biological imaging, data storage and organic light-emitting diodes.
“The ability to move light energy from one wavelength to another, more useful region, for example, from red to blue, can impact any technology that involves photons as inputs or outputs,” he said.
Lead images via U.S. Air Force, sunlight image via Ibrahim Iujaz