Higher efficiency organic solar cell created by UCSB Nobel Laureate and research teamJuly 13, 2007(Santa Barbara, Calif.) -- Using plastics to harvest the energy of the sun just got a significant boost in efficiency thanks to a discovery made at the Center for Polymers and Organic Solids at the University of California, Santa Barbara. Nobel laureate Alan Heeger, professor of physics at UC Santa Barbara, worked with Kwanghee Lee of Korea and a team of other scientists to create a new "tandem" organic solar cell with increased efficiency. The discovery, explained in the July 13 issue of the journal Science, marks a step forward in materials science. Tandem cells are comprised of two multilayered parts that work together to gather a wider range of the spectrum of solar radiation -- at both shorter and longer wavelengths. "The result is six and a half percent efficiency," said Heeger. "This is the highest level achieved for solar cells made from organic materials. I am confident that we can make additional improvements that will yield efficiencies sufficiently high for commercial products." He expects this technology to be on the market in about three years. Heeger and Lee have collaborated for many years on developing solar cells. The new tandem architecture that they discovered both improves light harvesting and promises to be less expensive to produce. In their paper, the authors explain that the cells "- can be fabricated to extend over large areas by means of low-cost printing and coating technologies that can simultaneously pattern the active materials on lightweight flexible substrates." The multilayered device is the equivalent of two cells in series, said Heeger. The deposition of each layer of the multilayer structure by processing the materials from solution is what promises to make the solar cells less expensive to produce. "Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives," wrote the authors. The cells are separated and connected by the material TiOx, a transparent titanium oxide. This is the key to the multilayer system that allows for the higher-level efficiencies. TiOx transports electrons and is a collecting layer for the first cell. In addition, it acts as a stable foundation that allows the fabrication of the second cell, thus completing the tandem cell architecture. Heeger shared the Nobel Prize in Chemistry in the year 2000, with Alan MacDiarmid and Hideki Shirakawa, for the "discovery and development of conducting polymers." The tandem solar cells reported in the Science article utilize semiconducting polymers from the class of materials that were recognized by the award of the Nobel Prize. With Howard Berke, Heeger in 2000 co-founded Konarka Technologies, based in Lowell, Mass., to develop and market solar cells based on this technology. Heeger recently was presented with the Italian Prize for Energy and the Environment (Eni Italgas Prize) for his discoveries and research accomplishments in the field of "plastic" solar cells. The Italian agency cited Heeger "for research that will begin to contribute to the energy needs of our planet in the near future." An exciting aspect of the latest discovery is that it is expected to contribute to third world usage of technologies such as laptop computers in areas that are "off the electricity grid." University of California - Santa Barbara |
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| Related Solar Cell Current Events and Solar Cell News Articles Nanometric butterfly wings created A team of researchers from the State University of Pennsylvania (USA) and the Universidad Autónoma de Madrid (UAM) have developed a technique to replicate biological structures, such as butterfly wings, on a nano scale. The resulting biomaterial could be used to make optically active structures, such as optical diffusers for solar panels. Looking deeply into polymer solar cells Researchers from the Eindhoven University of Technology and the University of Ulm have made the first high-resolution 3D images of the inside of a polymer solar cell. Carbon nanotubes could make efficient solar cells Using a carbon nanotube instead of traditional silicon, Cornell researchers have created the basic elements of a solar cell that hopefully will lead to much more efficient ways of converting light to electricity than now used in calculators and on rooftops. Bringing solar power to the masses On a 104-degree Friday in July when sunlight bathed The University of Arizona campus, doctoral student Dio Placencia sat before a noisy vacuum chamber in the Chemical Sciences Building trying to advance the renewable energy revolution. Plastics that convert light to electricity could have a big impact Researchers the world over are striving to develop organic solar cells that can be produced easily and inexpensively as thin films that could be widely used to generate electricity. NIST scientists study how to stack the deck for organic solar power A new class of economically viable solar power cells-cheap, flexible and easy to make-has come a step closer to reality as a result of recent work* at the National Institute of Standards and Technology (NIST), where scientists have deepened their understanding of the complex organic films at the heart of the devices. Nanopillars Promise Cheap, Efficient, Flexible Solar Cells Researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory and the University of California at Berkeley have demonstrated a way to fabricate efficient solar cells from low-cost and flexible materials. Low-cost solution processing method developed for CIGS-based solar cells Though the solar industry today predominately produces solar panels made from crystalline silicon, they remain relatively expensive to make. Flexible Solar Strips Light Up Campus Bus Shelter There won't be anymore waiting in the dark at this campus bus shelter. New flexible solar cell technology developed by a group of engineering researchers at McMaster University has been installed to power lighting for night-time transit users. Lasers are making solar cells competitive Solar electricity has a future: It is renewable and available in unlimited quantities, and it does not produce any gases detrimental to the climate. More Solar Cell Current Events and Solar Cell News Articles |
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