What is the definition and classification of luminescence?

Compared with the heat radiation, the light emission phenomenon that the absorbed energy is transformed into the non-equilibrium radiation state directly by the object without passing through the thermal stage is called "luminescence" . The solid material with such luminescence phenomenon is called "Luminescence" as the solid luminescent material. It is usually divided into different types according to the mode of excitation and the duration of luminescence.

1. Classification by mode of excitation

(1)Photoluminescence (Photo Luminescence, PL).

Luminescence excited by light (electromagnetic radiation) is widely used in the field of solid state exciter and fluorescent lamp. There are many kinds of photoluminescence materials, such as fluorescent lamp  luminescent material, plasma display luminescent material, long afterglow luminescent material and up-conversion luminescent material, etc.

(2)Cathodo Luminescence (CL2).

Using electron beam to excite luminous substance, the electron energy is very high, some even reach ten thousand electron volts, some devices display screen (such as computer CRT display) adopt this kind of luminous way.

(3)Electroluminescent (ELL).

It is also called "field luminescence", which is produced by current or electric field. The light emitting diode (LED) mentioned above belongs to this type of luminescence, which is emitted when the current is loaded into the P-N junction.

(4) Irradiating luminescence.

X-ray, a ray, β ray, ray and so on high energy ray excites the luminescence. The most commonly used equipment is an increase in medical X-ray photography screen, X-ray screen.

(5) Chemiluminescence (Chemi ninecene) excited luminescence by chemical reaction. This luminous energy originates from the chemical energy released by chemical reactions.

(6) sonoluminescence  is a relatively new method of luminescence, originally found in water.

Solution, under the action of sound pressure has the phenomenon of luminescence.

(7)Tribological luminescence lminesenece is loading friction onto solid material of luminescence.

(8)Bioluminescence (bioluminescence). Luminescence occurring in organisms and their extracts independent of the absorption of light. In theory, bioluminescence is a special kind of luminescence that depend on chemiluminescence

2. Classification according to luminous duration

One of the basic characteristics of solid state luminescence is that when excitation stops, the luminescence process does not end immediately, but gradually weakens until it finally disappears, that is, the afterglow after glow  is observed. Generally, luminescence is divided into two categories according to duration: those less than this time are called fluorescence, and those that are larger than this time are called fluorescence phosphorescence.

This article is from Allicdata Electronics Limited which offer a varity of component made by the solid luminescent material.