Electroluminescence

From Canonica AI

Introduction

Electroluminescence (EL) is an optical 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 from black body light emission resulting from heat (incandescence), from a chemical reaction (chemiluminescence), sound (sonoluminescence), or other mechanical action (mechanoluminescence).

History

The phenomenon of electroluminescence was discovered in 1907 by the British experimenter H. J. Round of Marconi's labs, using a silicon carbide crystal and a cat's-whisker detector. Soviet inventor Oleg Losev reported creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, but no practical use was made of the discovery for several decades.

A close-up of a material demonstrating electroluminescence.
A close-up of a material demonstrating electroluminescence.

Mechanism

Electroluminescence is a result of radiative recombination of electrons and holes in a material, usually a semiconductor. The excited electrons release their energy as photons - light. Prior to recombination, electrons and holes may be separated either by energy, as in a light-emitting diode (LED), or by physical distance, as in a photovoltaic cell. The impact of an electron on an atom can also excite an electron from its ground state into a higher energy level.

Types of Electroluminescence

There are several types of electroluminescence, including:

Applications

Electroluminescence has found widespread application in many areas of technology, including:

See Also