typical silicon PV cell is composed of a thin wafer consisting of
an ultra-thin layer of phosphorus-doped (N-type) silicon on top of
a thicker layer of boron-doped (P-type) silicon. An electrical
field is created near the top surface of the cell where these two
materials are in contact, called the P-N junction. 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
of photovoltaic cell.
Regardless of size, a typical silicon PV cell produces about 0.5
– 0.6 volt DC under open-circuit, no-load conditions. The
current (and power) output of a PV cell depends on its efficiency
and size (surface area), and is proportional 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 cm^2 (~25 in^2) will produce about 2 watts peak power.
If the sunlight intensity were 40 percent of peak, this cell would
produce about 0.8 watts.