How does a solar cell change light into electrical
All solar power devices that I know about operate by
getting the light to separate charges - basically to
move an electron from where it would like to be. This is
also the principle that chlorophyll in plants uses.
If you can maintain that separated charge, you get energy
just as in an electrical capacitor. The actual operation
is usually a little more complicated (inducing an excess
current in a semiconductor for instance) but that
is the basic idea - the light energy goes into exciting
an electron into a state away from where it best cancels
the charge on the atom it was attached to.
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Update: June 2012