Photovoltaic Effect

The photovoltaic effect is a physical phenomenon in which a semiconductor material generates electric energy upon exposure to light, closely related to the photoelectric effect since both involve light exciting an electron or other charge carrier to a higher energy state. The two are distinguished by what happens next: the photoelectric effect describes the electron being ejected out of the material, usually into a vacuum, while the photovoltaic effect describes the excited charge carrier remaining within the material. In both cases an electric potential is produced by the separation of charges, and the light must carry enough energy to overcome the potential barrier to excitation; the photovoltaic effect is the physical basis of solar cells.