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How it works
A typical silicon PV cell is composed of a thin wafer consisting of an
ultra-thin layer of phosphorus-doped silicon on top of a thicker layer of
boron-doped silicon. An electrical field is created near the top surface
of the cell where these two materials are in contact. When sunlight
strikes the surface of a PV cell, this electrical field provides momentum
and direction to light-stimulated electrons, resulting in a flow of current
when the solar cell is connected to an electrical load.
Regardless of size, a typical silicon PV cell produces about 0.5 - 0.6 volt
DC under no-load conditions. The current (and power) output of a PV
cell depends on its efficiency and surface area, and is proportional to
the intensity of sunlight striking the surface of the cell. For example,
under peak sunlight conditions a typical commercial PV cell with a surface area of 160 cm2 (~25 in2) will
produce about 2 watts peak power. If the sunlight intensity were 40 percent of peak, this cell would produce about 0.8 watts.
The U.S. Department of Energy has produced a video of how a PV cell works: Take a look!
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