Sulfide, sulfur oxides and yttrium oxide systems

The base cations of sulphide red phosphors are mainly alkalic metals, which have been applied to a certain extent on white LED. The activator ion of this kind of phosphor is EU, because the transition from f layer to d layer of EU  belongs to the parity allowable absorption migration, and the oscillator intensity is higher. It can obtain a wide excitation spectrum which can cover the emission wavelengths of (near) ultraviolet and blue light LED chips. The red sulfides phosphors, represented by SrS, are red phosphors with high luminescence efficiency. Under the excitation of (near) ultraviolet and blue light, red phosphors with good color purity of 620nm and 650nm are emitted. In CaS red phosphors, mutual doping often improves the luminescence performance.

Red phosphors were synthesized by adding Ca into SrS substrate by solid state reaction. The researchers found that the concentration of red phosphors was increased.

The emission peak of the sample is shifted to the direction of long wave and the intensity is enhanced. Researchers prepared red phosphors for LED with Cas as the main substrate. The results showed that the peak position of the main emission peak shifted from 633.2 nm to 613.1 nm, and the emission intensity increased with the increase of concentration. The addition of luminescent ions in the matrix can improve the luminescence intensity of alkaline earth sulfide phosphors. The addition of fluxes and carbohydrates in the sintering process can increase the crystallinity of the samples and improve the roundness of the phosphor particles, so the luminescence intensity can be increased.

Luminescence Properties of Red Phosphors for White LED

Sulfur oxides, yttrium oxide matrix red phosphors are usually activated with an ion.There are excitation peaks near 380nm and 460 nm.

Due to the effect of luminescent properties, the phosphors increase their energy absorption and thus improve the luminescence efficiency of the phosphors.

This article is from Allicdata Electronics Limited which offer a varity of white LED made by the red phosphors.

White LED : L130-6580001400001