How to synthesize phosphor?

Here are three methods to synthesize phosphors:

1.Spray pyrolysis

In recent years, various inorganic functional materials were prepared by spray pyrolysis that is favor by the researchers. The basic principle of spray pyrolysis is that the raw materials are first mixed with solvents (such as water and ethanol) to form a solution. When the solution passes through the spray device, the spray droplets come into contact with the hot substrate, because of the rapid volatilization of the solution and the thermal decomposition of the reactant. Fine powder will deposit on the substrate. The morphology of the phosphors prepared by this method can be controlled to some extent by the selection of precursor, concentration, droplet size, and the residual time of reactants in the furnace. The phosphors obtained by spray pyrolysis have good physical properties. For example, YAGCe phosphors synthesized by this method have spherical morphology and narrow size distribution, so they are suitable to be coated on blue LED chips.

The comparison of the advantages and disadvantages of the above methods. From the point of view of improving the luminescent properties of phosphors, it is still the focus of the research to explore the appropriate preparation technology.

2.Hydrothermal synthesis

Hydrothermal method is a novel method for the synthesis of phosphors. This method is mainly to make the solution under a certain pressure, appropriate temperature chemical reaction, the whole reaction process is carried out in the reactor, The temperature of synthesis is generally 100 ~ 1000 °C and the pressure is generally 1 M ~ 1 GPa, which is suitable for the preparation of new compounds and materials that can not be prepared by other methods. The advantages of hydrothermal synthesis are that the synthesis temperature is medium and low temperature, the energy consumption is low, the applicability is wide, the synthesis process is simple and easy to be sintered at high temperature, the product has good crystallinity, no crystal defect and good dispersibility. The reaction is carried out under the condition of sealing, and the atmosphere can be controlled, which can realize the preparation of the phase which can not be synthesized by other means.

3.Precipitation method

Preparation of phosphors by precipitation is a method of precipitating solutes from homogeneous solutions to synthesize phosphors. Coprecipitation is a method for preparing phosphor powder by precipitating a variety of precipitates at the same time. The basic theory of the precipitation method is the equilibrium between the multiphase ions of the insoluble electrolyte. The reaction process covers the generation, dissolution and transformation of the precipitate, which is related to the concentration of solute, the pH of the solution, the temperature of the solution, etc. By adjusting these factors, the precipitation state of the precipitate can be controlled, and the precursor of the phosphor can be obtained by heating the precipitate until decomposed. Finally, the precursor can be obtained by sintering the precursor. The advantages of preparing phosphors by precipitation method are: high purity, small particle size, good dispersion, uniform particle size, low synthesis temperature and simple operation. Its main shortcomings are: the sedimentation of glue is difficult to wash and filter; the precipitant impurities are easily introduced into the phosphor; if the quality control is not good in the process of precipitation, it is easy to produce component segregation.

This article is from Allicdata Electronics Limited.