|a photovoltaic cell that produces electricity from the sun's rays, used esp in spacecraft|
(click for larger image in new window)
A photoelectric cell designed to convert sunlight into electrical energy, typically consisting of layers or sheets of specially prepared silicon. Electrons, displaced through the photoelectric effect by the Sun's radiant energy in one layer, flow across a junction to the other layer, creating a voltage across the layers that can provide power to an external circuit. Solar cells are used as power supplies in calculators, satellites, and other devices, and as a primary source of electricity in remote locations.
Note: At present, solar cells are too expensive and inefficient to be used for commercial generation of electricity.