From Sunlight to Electricity: How Solar Cells Work

Nearly all of our electricity generation options involve converting mechanical energy into electrical energy—usually using a dynamo or turbine. The significant exception is photovoltaics, in which sunlight is converted directly into electricity—with no moving parts.

Photovoltaic (PV) cells use a phenomenon called the photovoltaic effect to generate electricity. A cell is made of a semiconductor material—a material that conducts electricity but whose electrical conductivity can be altered by adding small quantities of other elements (a process referred to as doping). Crystalline silicon is the most common semiconductor used, though other materials are being used as well, including amorphous silicon, cadmium-telluride (CdTe), gallium arsenide (GaAs), and copper indium gallium (di)selenide (CIGS). Most of these alternatives are being tried in an effort to reduce costs.