The luminescence is the emission of light by a substance without being driven by the heat , so it is a form of radiation cold, is the process of light emission whose origin lies not only at high temperatures can be caused by chemical reactions , electrical energy, subatomic movements, or stress in a crystal. This distinguishes luminescence from incandescence , which is the light emitted by a substance as a result of its heating. Historically, radioactivity was considered to be a form of “radio-luminescence”, although today it is considered a separate phenomenon, as it involves more than electromagnetic radiation. The term luminescence It was introduced in 1888 by Eilhard Wiedemann .
Summary
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- 1 Types of Luminescence
- 2 Luminescence in Nature
- 3 Applications
- 4 References
Luminescence Types
The following are the types of luminescence
- Chemiluminescence , which is the result of a chemical reaction.
- The bioluminescence , chemiluminescence although generally, is when performed by a living organism.
- Electrochemiluminescence is the result of an electrochemical reaction.
- Crystalloluminescence , produced during crystallization
- Electroluminescence is the result of an electric current that passes through a substance.
- Triboluminescence , a result of mechanical action on a solid
- Photoluminescence , a result of photon absorption
- Fluorescence is a type of photoluminescence, in which the emitted photons are of lower energy than the absorbed ones.
- Phosphorescence is a slightly delayed fluorescence after the initial absorption of radiation (on a scale of seconds to hours)
- Radioluminescence , is the result of bombardment of a substance with ionizing radiation
- Sonoluminescence , a result of implosion of bubbles in a liquid when excited by sound
- Thermoluminescence , the re-emission of light absorbed when a substance is heated
Luminescence in Nature
Bioluminescence in the sea caused by microscopic organisms
One of the earliest examples of luminescence ever observed was the sometimes visible phosphorescent effect on the ocean surface at night, an effect scientists now know is caused by materials in the bodies of organisms known as dinoflagellates. Within the body of a dinoflagellate there are substances such as luciferase and luciferin , which chemically react with oxygen in the air above water and produce light with minimal levels of heat. Despite the fact that dinoflagellates are microscopic creatures, in large quantities they produce a visible shine.
Dinoflagellates are not the only bioluminescent organisms in the ocean. Jellyfish, as well as various species of worms, shrimp, and squid produce their own light through phosphorescence. This is particularly useful for living things in what is known as the mesopelagic zone, at a depth ranging from 200 to 1,000 m below the ocean surface, where sunlight hardly reaches.
Another example of natural luminescence is that of fireflies and guinea pigs , insects that, although not related, use the same bioluminescent mechanisms.
Applications
Luminescent chemicals
Luminescence in each of its types has many applications in human life. The Cuban aborigines, and later the maroons, used lamps made with pierced güiras filled with cocuyos.
Low consumption light bulbs (known in Cuba as savers) and fluorescent lamps use the principle of fluorescence to generate light using less electrical energy than other types of lamps, such as fluorescent lamps. Another example of this situation is Mercury Vapor Lamps .
Phosphorescent materials are used to coat elements that are desired to be visible in the dark, given the characteristic of these components that they generate light long after the excitation radiation has ceased. This is mostly used in measuring instruments such as watches, thermometers, compasses, aircraft navigation controls, etc.
The light emitting diodes (LED) emits light through an electro-luminescent phenomenon.
Luminescence is also used to perform precision measurements, such as phosphor thermometry, temperature measurement with phosphorescence, and luminescent and fluorescent spectrography.
