Phosphorescent Ceramic Afterglow effect

Effects of the semiconductor light emitting afterglow phenomenon due to incident light, and the light emitting diode is a semiconductor light emitting phenomenon caused by the electric field. Photoinduced effect afterglow effect and has a decorative gravels‍ close relationship. Photoinduced effect refers to the valence band electrons are incident photon excitation, will jump across the forbidden band into the conduction band. If the conduction band electrons are excited back to the valence band and the transition will emit photons in the form of energy release, which is photoinduced effect, also known as: fluorescence effect. 

Photoluminescence phenomenon will no longer produce metal. Since the metal, the valence electron band is not filled, only fluorescent paint‍ low levels of electron excitation to the valence band energy level of the same. At the same valence band electron luminescent sheets transitions from the high energy level back to a low energy level, the energy released is too small, long-wave photons produced, far exceeding the wavelength of visible light. In certain ceramics and semiconductors, the band gap between the valence band and the conduction band clique, the excited electrons jump over the forbidden band from the conduction band, which is released back to the valence band of the photonic band in the visible wavelength exactly. Such materials are referred to: fluorescent material.