A photocathode is a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound. When this is struck by a quantum of light (photon), the absorbed energy causes electron emission due to the photoelectric effect. ==Uses== For many years the photocathode was the only pr... Found on http://en.wikipedia.org/wiki/Photocathode
an element of a photoelectric cell (q.v.) that emits electrons when struck by light, making possible the flow of electric current through the ... [3 related articles] Found on http://www.britannica.com/eb/a-z/p/60