Effects of Charge Compensators on Structure and Luminescent Properties of Microwave Synthesized CaMoO4:Eu3+ Red Phosphors

Red phosphors CaMoO4:Eu3+ were synthesized by microwave method with MnO2 as microwave absorbent. The phase structure and luminescent properties of the as-synthesized phosphors were investigated by X-ray powder diffraction and Fluorescence spectrophotometer. The results show that when the reaction time was 40 min, microwave power was medium-high fire (~560 W), we got the tetragonal CaMoO4:Eu3+ pure phase. The excitation spectrum of CaMoO4:Eu3+ was composed by a broad band between 200 nm and 350 nm and a series of peaks from 350 nm to 500 nm. The main peak was at 305 nm. The emission spectrum was composed of a series of peaks in the range of 550~750 nm and the main peak was at 617 nm due to the 5D0→7F2 transition of Eu3+. Doping charge compensator Li+, Na+ or K+ could improve the luminous intensity of the sample. When the doping amount of Li+, Na+ or K+ were 8 mol%, the luminous intensity of the sample reached the maximum. The intensity of the emission peak at 617 nm was 4.04, 3.42, 3.48 times of sample without doping charge compensator.