Piezoluminescence

Piezoluminescence is a form of luminescence created by pressure upon certain solids. This phenomenon is characterized by recombination processes involving electrons, holes and impurity ion centres. Some piezoelectric crystals give off a certain amount of piezoluminescence when under pressure, as in handheld cigarette lighters when the button is pressed. NaCl, KCl, KBr and polycrystalline chips of LiF (TLD-100) have been found to exhibit piezoluminescent properties. It has also been discovered that ferroelectric polymers exhibit piezoluminescence upon the application of stress.