Term: light-emitting diode (LED)
https://doi.org/10.1351/goldbook.LT07414

Definition:
semiconductor (often a combination of gallium, arsenic and phosphorous or gallium and nitrogen) containing an n region (where electrons are more numerous than positive charges) separated from a p region (where positive charges are more numerous than negative charges). Upon application of a voltage, charges move and emission of ultraviolet, visible or infrared radiation is produced each time a charge recombination takes place. Although a LED emits incoherent monochromatic light, normally a very narrow frequency range is obtained.

Notes:
0) This effect is a form of @E01966@.
1) The colour depends on the semi-conducting material used, and can be @UT07492@, @VT07496@ or @IT07399@.
2) Organic light-emitting devices (OLEDs) contain diodes made of small molecules or made of @M03667@ materials. The latter are sometimes called PLEDs.

Related Terms:
1) electroluminescence (http://doi.org/10.1351/goldbook.E01966).
2) ultraviolet (http://doi.org/10.1351/goldbook.UT07492).
3) visible (http://doi.org/10.1351/goldbook.VT07496).
4) infrared (http://doi.org/10.1351/goldbook.IT07399).
5) polymeric (http://doi.org/10.1351/goldbook.M03667).
6) semiconductor (http://doi.org/10.1351/goldbook.S05591).
7) charge recombination (http://doi.org/10.1351/goldbook.C00998).
8) frequency (http://doi.org/10.1351/goldbook.F02525).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 364 (https://doi.org/10.1351/pac200779030293)

Citation: 'light-emitting diode (LED)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.LT07414

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