Electroluminescence (EL) is an optical phenomenon and electrical phenomenon where a material emits light in response to an electric current passed through it, or to a strong electric field.
This is distinct to light emission resulting from heat (incandescence) or from the action of chemicals (chemoluminescence).
Electroluminescence is the result of radiative recombination of electrons and holes in a material (usually a semiconductor).
The excited electrons release their energy as photons - light.
Reff:https://www.sciencedaily.com/terms/electroluminescence.htm