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WFU gives solar cells an energy boost:
Researchers double the efficiency of plastic cells
May 5 - McClatchy-Tribune Regional News - M. Paul Jackson Winston-Salem Journal, N.C. Researchers at Wake Forest University have increased the efficiency of plastic solar cells to more than 6 percent, double the previous standard of 3 percent. "Six percent is a big number," said David Carroll, the director of the Center for Nanotechnology and Molecular Materials at WFU. "You've now got a device that's good enough to start thinking about a commercial product." The findings will be published in the journal Applied Physics Letters. The technological advance came after nearly four years of research. Carroll said Thursday that the nanotechnology center is working with WFU's Office of Technology Asset Management to license some of its research. The office licenses technologies developed by the university and helps to put them into commercial use. Solar-cell development still has a ways to go, however. To be considered commercially viable, solar cells must be able to convert about 8 percent of the sun's light into useful energy, experts said. "Within two years, we have more than doubled the 3 percent mark," Carroll said. "I fully expect to see higher numbers within the next two years." According to the center, it increased the efficiency of flexible, plastic solar cells by creating "nano-filaments" within the plastic, similar to the veins in tree leaves. The filaments are designed using nanotechnology and allow researchers to create thicker solar cells to absorb more sunlight. A solar cell absorbs sunlight and uses that light to stimulate electrons within the solar cell. The stimulated electrons generate an electrical current, which can then be passed into calculators, car batteries and other devices through an external circuit. Plastic solar cells are lighter and cheaper than traditional, silicon solar panels and can be used to provide electricity and heat. Silicon panels can convert about 12 percent of the light that hits them into useful electrical power -- but those panels are usually heavier and bulkier. Carroll said that researchers will eventually create plastic solar cells that are just as efficient as silicon panels. "Plastics are here," he said. "Plastics can do the same job that silicon can do. That's a huge statement." The WFU center is using nanotechnology to develop household products and new medical treatments. Nanotechnology is the science of creating material on the atomic scale and using those materials to design other products. The region is betting heavily on the nanotech industry to help it transition from its traditional manufacturing economy. The new plastic solar cells could help attract solar-cell companies and jobs to the area, said Peggy Low, the senior vice president of technology for the Greater Winston-Salem Chamber of Commerce. "That brings a lot more recognition to Wake Forest and Winston-Salem and the Triad for its nano-expertise," Low said. The plastic solar cells typically used about 3 percent of the sun's light for power until 2005, when the Wake Forest center increased their efficiency to about 5 percent. -- M. Paul Jackson can be reached at 727-7473 or at mjackson@wsjournal.com. To subscribe or visit go to: http://www.wsjournal.com |