Preparation and Photoluminescence Properties of Green-emitting Vanadate Phosphor Ca_5Mg_4(VO_4)_6

Green-emitting vanadate phosphor Ca5Mg4(VO4)6 was synthesized via a solid-state reaction route.The phase composition,morphology and photoluminescence properties of the synthesized phosphors were characterized by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,Raman spectroscopy,and fluorescence spectrophotometer,respectively.The influences of firing temperature and heat-treatment on photoluminescence properties of the phosphor were investigated.The results indicate that single phase of Ca5Mg4(VO4)6 is obtained after heat treatment.The phosphor particles showed a short cylindroid with the length of about 5 μm and the diameter of about 2 μm.All the phosphors had an intensive green emission peak at about 510 nm under 365 nm excitation.The intensity of photoluminescence(PL) and photoluminescence excitation(PLE) increased,and the position of excitation peak exhibited a red-shift with the increase of the firing temperature.The intensity of PL and PLE firstly increased and then decreased,and the position of excitation peak howbeit appeared a red-shift with the increase of the heat treatment temperature.The phosphor fired at 700 ℃ for 5 h and subsequent heat-treated at 900 ℃ for 8 h had greatest emission intensity under 365 nm excitation.