Commonly referred to as phosphorescence, persistent luminescence is the emission of light by a phosphorescent material after an excitation by ultraviolet or visible light.
[2][3] In fluorescence, the lifetime of the excited state lasts a few nanoseconds.
In phosphorescence, even if the emission lives several seconds, this is due to deexcitation between two electronic states of different spin multiplicity.
Afterward, the stored energy is gradually released to light emitter centers, usually by a fluorescence-like mechanism.
Persistent luminescence materials are mainly used in safety signs, watch dials, decorative objects and toys.