| Cars Powered by the Sun - Science Insider
Reported February 2009
ABOUT SOLAR CELLS: The solar cells on calculators and satellites are photovoltaic cells or modules: groups of cells electrically connected and packaged together. Photovoltaics convert sunlight directly into electricity. Photovoltaic cells are made of semiconductor materials like silicon. When light strikes the cell, a certain portion of the light is absorbed by the semiconductor material. The energy of the absorbed light knocks electrons in the semiconductor material loose, allowing them to flow freely. Photovoltaic cells also have one or more electric fields that act to force the freed electrons to flow in a certain direction. This flow of electrons is a current. By placing metal contacts on the top and bottom of the photovoltaic cell, the current can be drawn off to be used. For example, the current can power a calculator. However, at a larger scale conventional photovoltaic panels made from silicon to provide electricity are expensive, and thus not cost-competitive with electricity from the power grid.
The Institute of Electrical and Electronics Engineers, Inc., the Materials Research Society, the American Mathematical Society, and the Mathematical Association of America contributed to the information contained in the TV portion of this report.
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Steve Hechtman
Electrical Engineer
University of Michigan
(703) 635-5804
shechtma@umich.edu
Institute of Electrical and Electronics Engineers, Inc. IEEE-USA
Washington, DC 20036-5104
(202) 530-8353
http://www.ieee.org
ieeeusa@ieee.org
Materials Research Society
Warrendale, PA 15086-7573
724) 779-3003
webmaster@mrs.org
Mike Breen and Annette Emerson
American Mathematical Society
Providence, RI 02904-2294
(800) 321-4267
http://www.ams.org
paoffice@ams.org
Ivars Peterson
Mathematical Association of America
Washington, DC 20036-1358
(800) 741-9415
ipeterson@maa.org
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