Photoelectric Effect

The photovoltaic effect is the basic process by which a solar cell converts sunlight into electricity. French physicist Edmund Becquerel discovered the photovoltaic effect in 1839 while studying an electrolytic cell with two metal electrodes.¹ When a solar PV cell absorbs photons - "packets" of energy corresponding to different wavelengths of light - the light's energy is transferred to an electron in an atom of the PV cell's semiconductor, releasing the electron to form an electrical circuit between two electrodes.²

This phenomenon is similar to the photoelectric effect, in which matter (usually metal) absorbs electromagnetic radiation (visible light or ultraviolet light) and consequently emits electrons, or photoelectrons.  Heinrich Hertz first noted the photoelectric effect in 1887 when he showed the electrodes exposed to ultraviolet light emit sparks more easily.For more information on the photoelectric effect, see this cartoon illustration by the University of Colorado at Boulder.