03 July 2012
Researchers at the North Carolina State University (NCSU) in Raleigh, North Carolina (US) may have found a way to significantly enhance solar absorption using sandwiched nanostructures. The technique would allow manufacturers to produce much thinner, thus, much cheaper, solar cells in less time while maintaining or even improving conversion efficiency.
What makes this structure and its production process unique and appealing is that “it is perfectly compatible with existing manufacturing processes of thin-film solar cells in the industry,” says Linyou Cao, Assistant Professor in NCSU’s Department of Materials Science and Engineering. “This technique can substantially decrease the cost and improve the efficiency of solar cells. It will help facilitate the generation of affordable solar electricity.”
With this sandwich design, the active absorption layer could be “one order of magnitude thinner,” Cao explains. “For instance, this structure can absorb 90% solar radiation using 70 nanometers of amorphous silicon.” That absorption capability would typically require a thickness of 300 to 500 nm. The scientist, whose group works on the forefront of nanoscale photophysics and photochemistry, believes manufacturers will be able to apply this technique to many other solar cell materials and names cadmium telluride, copper indium gallium selenide and organic materials as possible candidates.
Cao describes the design of the sandwiched solar cell: “In the sandwich structure, a layer of absorbing semiconductor materials is sandwiched in the middle of two non-absorbing dielectric layers. The production of this sandwiched structure first requires patterning a substrate with dielectric nanostructures using nanofabrication techniques, followed by conformably coating the nanostructure with a layer of semiconductor materials and then a layer of dielectric materials using standard deposition techniques.” Cao’s team is still working on demonstrating and optimizing the solar cell in the lab and expects to produce high-performance solar cells soon.
What would have to happen for his research breakthrough to make it into the real world? Cao has one word: “Money.” They have only just begun working on the technique and are looking for resources from federal funding agencies or industry partners. Cao’s outlook, though, is optimistic. “If everything goes well, I expect this technology to be commercialized in three to five years,” he says.
Written by Sandra Henderson, Research Editor, Solar Novus Today
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