Solar Cells Get an Upgrade

Submitted by Nina M. Riccio on August 6, 2012

Assistant Professor Ryan Munden has some ideas about solar energy panels. Specifically, he wants to make them more efficient and ultimately more economical. And he’s been working out his design at Long Island’s Brookhaven National Laboratory, spending several days a week there last semester when he was on sabbatical.

Sponsored by the U.S. Dept. of Energy, the facilities and staff of Brookhaven are open to all scientists whose proposals have been approved by the Brookhaven administration.

Nanopillar formations, etched from a solid piece of silicone wafer and viewed under a Scanning Electron Microscope

Dr. Munden’s idea is based on the theory that creating nanopillars would convert solar energy more efficiently than the flat surface currently in use. This theoretical work has been around for several years, but thus far there has been no solid evidence that it can be achieved. “Right now, the solar cells currently in use are like mirrors. [Even though they are coated with a non-reflective coating] light bounces off the mirrors, so some of that solar energy is lost,” Dr. Munden explains. “Now, consider a fuzzy blanket; the many fibers stand up on the surface, absorbing light much more efficiently. These nanopillars need to be roughly the size of photons, or about 300-700 nanometers.” They may ultimately be created using masking plus wet etching, or eventually by growing nanowires, which would be more cost effective than using the current nanofabrication.

The second hoped-for advantage of Dr. Munden’s work involves enhancing the extraction of electrons at the junction of the silicon layers of the solar cell.

The project is approved for two years, at which time Dr. Munden will submit a new proposal to continue working at Brookhaven. He hopes that the later stages of development will provide opportunities for graduate and undergraduate student internships. “A student interested in microprocessing or photovoltaics would find the work very beneficial,” he says.

“If I can prove the concept, it would be worth the time to develop ways to mass produce the cells,” Dr. Munden says. He is currently seeking funding from various sources.


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