What are the materials of composition of luminescent ?

The solid state luminescent material is composed of two parts: the matrix host part and the activator part.

The former is the main component of the luminescent material, while the latter is the doped component. Activators play a decisive role in the luminescence properties of luminescent materials, and they directly affect the luminescence.The strength, quality and other indicators, generally add a very small amount. In writing, it is generally behind the matrix material. In addition, the addition of another kind of impurity to the matrix, if it improves the luminescence, This impurity is called co-activator, and the activator that enhances the luminescence intensity of activator is called activator,sensitizer.

There are many matrix elements in the periodic table for phosphor luminescent materials. It mainly includes oxides (such as yttrium oxide, gadolinium oxide, rare earth sulfur oxide), oxygenates (such as aluminate, silicate, phosphate, germanate) and composite systems of many elements (such as tungsten molybdate). The conditions are as follows: the cationic electronic structure has closed shell configuration or inert gas electron configuration, the cationic ion must be optically transparent, and the crystal has some defects.

The fundamental cause of luminescence is the transition of activator ions between ground state (g) and excited state (E). However, not all transitions can produce light emission. The luminescent electron transitions of activator ions must follow certain selection rules, which mainly include the following two kinds of rules.

1) Parity selection rule. Electron (electric dipole transition) transitions between energy levels with the same parity are not allowed.

2)Spin selection rule. Electron transitions between different spin states are not allowed.

In the case of solids, the above selection rules are not strictly prohibited, and sometimes relaxation occurs, which is closely related to the mixing of correlation wave functions.

This article is from Allicdata Electronics Limited.