Synthesis And Fluorescence Enhancement Of Red Phosphor Gd₂(MoO₄)₃: Eu³⁺ And ZnMoO₄:Eu³⁺ By Codoping

White LEDs with high luminous efficiency, long life, energy saving and green have attracted more and more attention. Currently, the most mature technology for the preparation of white LED is light conversion method of phosphor coating. Therefore, phosphors with high efficiency and stability under excitation of ultraviolet light or blue become the research hotspot of white LED. The parameters of luminescent efficiency, chromaticity parameters and the price of LEDs are the most important indicators which are determined by the LED chips and the conversion material coated on. In this study, We selected Gd2(MoO4)3:Eu3+ and ZnMoO4:Eu3+ phosphors as research objects for improving the emission intensity by co-doping with some other cheap elements for the purpose of reducing cost.Gd2-x(MoO4)3:xEu3+(x=1.0) phosphors emit red fluorescence under excitation of near ultraviolet (395 nm) and blue (466 nm). Their optimum synthesis temperature was found to be 950℃and their luminous intensity can significantly be improved by the doping of PO43- and alkali metal. The emission intensities of phosphors Gd2-x(MoO4)3:xEu3+(x=1.0), GdEu(MoO4)2.85(P04)0.10,GdEu(Mo04)2.8(PO4)0.2Li0.2 and GdEu(MoO4)2.8(PO4)0.2Na0.2 under excitation of 395 nm are 1.36 times,1.69 times and 1.57 times than that of Gd(MoO4)3:Eu3+ respectively. On the other hand, phosphor Li0.5Gd0.5-xMoO4:Eu3+x with x=0.125 shows stronger luminescence emission than Na0.5Gd0.375MoO4:Eu0.1253+. Meanwhile, the fluorescence intensity of phosphors of calcium molybdate systems can also be enhanced by phosphate doping.At the same time, we determined that the optimum calcination condition of Zn0.454MoO4:Eu0.25Li0.25Bi0.04Sm0.006 is at 750℃for 6h, and the fluorescence intensity of Zn0.5Li0.25Mo0.97O4:Eu3+0.25Si0.03 is 1.416 times as high as that of phosphor without doping of silicon. We also synthesized ZnMoO4-based phosphors of single-doped with Pr3+ or Dy3+, the former one emits red ligh at 643nm by 450nm excitation, and the later one emits yellow light at 577 nm by 354 nm.