http://www.eurekalert.org/pub_releases/2011-02/su-srd021811.phpPublic release date: 20-Feb-2011
Contact: Louis Bergeron
louisb3@stanford.edu
650-725-1944
http://news.stanford.edu/Stanford University>Stanford researchers develop new technology for cheaper, more efficient solar cells
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Stanford researchers have found that adding a single layer of organic molecules to a solar cell can increase its efficiency three-fold and could lead to cheaper, more efficient solar panels. Their results were published online in ACS Nano on Feb. 7.
Professor of chemical engineering Stacey Bent first became interested in a new kind of solar technology two years ago. These solar cells used tiny particles of semiconductors called "quantum dots." Quantum dot solar cells are cheaper to produce than traditional ones, as they can be made using simple chemical reactions. But despite their promise, they lagged well behind existing solar cells in efficiency.
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But solar cells made of a single material have a maximum efficiency of about 31 percent, a limitation of the fixed energy level they can absorb.
Quantum dot solar cells do not share this limitation and can in theory be far more efficient. The energy levels of electrons in quantum dot semiconductors depends on their size – the smaller the quantum dot, the larger the energy needed to excite electrons to the next level.
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http://pubs.acs.org/doi/abs/10.1021/nn103371v