Solar cell structure

A solar cell is an electronic device that directly converts sunlight into electricity. Light shining on a solar cell generates current and voltage to generate electricity. This process first requires a material in which the absorption of light lifts the electrons to a higher energy state, and second, the movement of this higher energy electron from the solar cell to the external circuit. The electrons then dissipate their energy in an external circuit and return to the solar cell. A variety of materials and processes may meet the requirements for photovoltaic energy conversion, but virtually all photovoltaic energy conversion uses semiconductor materials in the form of pn junctions.

Cross section of a solar cell.

The basic steps of solar cell operation are:

Illumination generates charge carriers;

The collection of carriers generates current;

Solar cells generate voltage

External load and battery internal resistance consume power.