Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions, or stress on a crystal. This distinguishes luminescence from incandescence, which is light emitted by a substance as a result of heating. Historically, radioactivity was thought of as a form of "radio-luminescence", although it is today considered to be separate since it involves more than electromagnetic radiation. The term 'luminescence' was introduced in 1888 by Eilhard Wiedemann.
The dials, hands, scales, and signs of aviation and navigational instruments and markings are often coated with luminescent materials in a process known as "luminising".
The following are types of luminescence:
- Chemiluminescence, the emission of light as a result of a chemical reaction
- Crystalloluminescence, produced during crystallization
- Electroluminescence, a result of an electric current passed through a substance
- Cathodoluminescence, a result of a luminescent material being struck by electrons
- Mechanoluminescence, a result of a mechanical action on a solid
- Triboluminescence, generated when bonds in a material are broken when that material is scratched, crushed, or rubbed
- Fractoluminescence, generated when bonds in certain crystals are broken by fractures
- Piezoluminescence, produced by the action of pressure on certain solids
- Sonoluminescence, a result of imploding bubbles in a liquid when excited by sound
- Photoluminescence, a result of absorption of photons
- Fluorescence, photoluminescence as a result of singlet–singlet electronic relaxation (typical lifetime: nanoseconds)
- Phosphorescence, photoluminescence as a result of triplet–singlet electronic relaxation (typical lifetime: milliseconds to hours)
- Raman Emission, photoluminescence as a result of inelastic light scattering, (lifetime: nanoseconds)
- Radioluminescence, a result of bombardment by ionizing radiation
- Thermoluminescence, the re-emission of absorbed energy when a substance is heated
- Cryoluminescence, the emission of light when an object is cooled (an example of this is wulfenite)
- Light-emitting diodes (LEDs) emit light via electro-luminescence
- Phosphors, materials that emit light when irradiated by higher-energy electromagnetic radiation or particle radiation
- Phosphor thermometry, measuring temperature using phosphorescence
- Thermoluminescence dating
- Thermoluminescent dosimeter
Luminescence occurs in some minerals when they are exposed to low-powered sources of ultraviolet or infrared electromagnetic radiation (for example, portable UV lamps), at atmospheric pressure and atmospheric temperatures. This property of these minerals can be used during the process of mineral identification at rock outcrops in the field, or in the laboratory.
- E. Wiedemann (1888) "Über Fluorescenz und Phosphorescenz, I. Abhandlung" (On fluorescence and phosphorescence, first paper), Annalen der Physik, 34: 446-463. From page 447: "Ich möchte für diese zweite Art der Lichterregung, für die uns eine einheitliche Benennung fehlt, den Namen Luminescenz vorschlagen, und Körper, die in dieser Weise leuchten, luminescirende nennen." [For this second type of light excitation, for which we lack a consistent name, I would like to suggest the name of "luminescence", and call "luminescing" [any] bodies that glow in this way.]
- A Brief History of Fluorescence and Phosphorescence before the Emergence of Quantum Theory Bernard Valeur and Mario N. Berberan-Santos J. Chem. Educ., 2011, 88 (6), pp 731–738 doi:10.1021/ed100182h
- Piezoluminescence phenomenon N. A. Atari Physics Letters A Volume 90, Issues 1-2, 21 June 1982, Pages 93-96 doi:10.1016/0375-9601(82)90060-3
- Meetei, Sanoujam Dhiren. "Synthesis, Characterization and Photoluminescence of ZrO2:Eu3+ Nanocrystals" (PDF). Retrieved 18 December 2014.
|Wikimedia Commons has media related to Luminescence.|