College Park, MD (August 17, 2010) -- Solar energy is an environmentally-friendly way of producing electricity and is considered to be one of the most appealing options for the future.
The basis for solar energy is absorbing light and then effectively disassociating electrical charges. As Yana Vaynzof, a University of Cambridge researcher, reports in the American Institute of Physics' Applied Physics Letters, conjugated polymers are excellent materials for such a system, thanks to their light absorption and conduction properties. Unfortunately, poor charge disassociation in these materials tends to inhibit their performance. Photo-induced charges remain closely bound and recombine before they can be collected for electricity.
With a goal of working around this, Vaynzof and colleagues studied the charge disassociation at an interface between an organic polymer, in which the light is absorbed, and an inorganic oxide layer.
"In particular, we discovered that modifying the interface with a self-assembled monolayer of molecules results in an increase of charge disassociation efficiency to nearly 100 percent," says Vaynzof. "Our measurements revealed that the molecular modification alters the energetic landscape of the interface so that the light absorbed in its vicinity is disassociated into charges that are then swept far from each other -- preventing them from recombination, much like two balls rolling away from each other on opposite sides of a hill."
This has significant implications for the organic solar cell industry because it offers an interesting solution to one of the field's most significant problems.
The article, "Improved Photoinduced Charge Carriers Separation in Organic-Inorganic Hybrid Photovoltaic Devices" by Yana Vaynzof, Dinesh Kabra, Lihong Zhao, Peter K-H. Ho, Andrew Thye Shen Wee, and Richard H. Friend appears in the journal Applied Physics Letters. http://apl.aip.org/applab/v97/i3/p033309_s1
Journalists may request a free PDF of this article by contacting jbardi@aip.org
ABOUT Applied Physics Letters
Applied Physics Letters, published by the American Institute of Physics, features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, Applied Physics Letters offers prompt publication of new experimental and theoretical papers bearing on applications of physics phenomena to all branches of science, engineering, and modern technology. Content is published online daily, collected into weekly online and printed issues (52 issues per year). See: http://apl.aip.org/
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Applied Physics Letters