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A light-emitting electrochemical cell (LEC or LEEC) is a solid-state device that generates light from an electric current (electroluminescence). LECs are usually composed of two metal electrodes connected by (e.g. sandwiching) an organic semiconductor containing mobile ions.
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes , releasing energy in the form of photons .
In these devices, bright, long-life light emission is achieved in thin-film yellow-emitting manganese-doped zinc sulfide material. Displays using this technology were manufactured for medical and vehicle applications where ruggedness and wide viewing angles were crucial, and liquid crystal displays were not well developed.
Since these materials have a high index of refraction, [note 1] design features of the devices such as special optical coatings and die shape are required to efficiently emit light. A LED is a long-lived light source, but certain mechanisms can cause slow loss of efficiency of the device or sudden failure.
Cryoluminescence, the emission of light when an object is cooled [6] (an example of this is wulfenite) Photoluminescence, a result of the absorption of photons Fluorescence, traditionally defined as the emission of light that ends immediately after the source of excitation is removed. As the definition does not fully describe the phenomenon ...
Phosphorescent organic light-emitting diodes (PHOLED) are a type of organic light-emitting diode (OLED) that use the principle of phosphorescence to obtain higher internal efficiencies than fluorescent OLEDs. This technology is currently under development by many industrial and academic research groups.
Solid-state lighting (SSL) is a type of lighting that uses semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma (used in arc lamps such as fluorescent lamps), or gas.
Light-emitting diode therapy (LEDT) is a clinical approach that applies different wavelengths of light to cure diseases or conditions with skin-safe lights. Following NASA's innovation in the 1990s with Light Emitting Diodes (LEDs) that emit a specific narrow light spectrum, LED Therapy (LEDT) showed significant potential. [ 1 ]