Red-emitting phosphors Ca0.7-x Eu0.3Z4（X=0, 0.02, 0.04, 0.06, 0.08, 0.1）were fabricated by a solid state reaction method using (NH4)6Mo7O24•4H2O, CaCO3, Eu2O3 and ZnO as raw materials at the temperature of 600°C, 700°C, 750°C, 800°C, 850°C and 900°C, respectively. Phase components, grain morphologies and luminescence spectrum properties of the samples were analyzed and studied by the X-ray diffraction (XRD), scanning electron microscope (SEM) and F-4500 spectrophotometer. XRD analysis showed, with the temperature increasing, the width of the diffraction peak became narrow, but the peak value increased indicating the degree of crystallization became better and pure Ca0.7 Eu0.3MoO4 phase can be obtained at 850°C. SEM analysis showed that below 800°C, the grain was small but contains lots defects, while above 850°C round-shaped regular grain of about 1µm can be obtained. Photoluminescence spectrum analysis showed the phosphors could be efficiently excited by a near- ultraviolet light with wavelength of 395nm or the blue-purple light with wavelength of 465nm, the emission peaks located at 592nm and 614nm respectively. The emitting intensity improved with the sintering temperature increased, and got the maximum value at 850°C, but a little decreased at 900°C. Zn2+ doping has no effect on emission peak position but can efficiently improve the emitting intensity of Ca0.7Eu0.3MoO4 and the best doping concentration is about X=0.08.
Zhengyi Jiang, Shanqing Li, Jianmin Zeng, Xiaoping Liao and Daoguo Yang
X. Zhang and Y. Cao, "Effect of Zn2+ Doping on Luminescence Properties of Red-Emitting Phosphors CaMoO4:Eu3+", Advanced Materials Research, Vols. 189-193, pp. 4308-4312, 2011