Voltage reduction in a non-uniformly illuminated solar cell

A simple mathematical expression is derived for the reduction in the voltage at the output terminals of a solar cell due to non-uniform illumination of the junction plane. The voltage from a solar cell non-uniformly illuminated by light is always less than that from a similar cell uniformly illuminated by light and generating the same amount of short-circuit current. For a small change in the voltage, an approximate expression predicts a constant shift in the I-V characteristics of a solar cell, towards the lower voltage side.