Morphology control and luminescence properties of YVO4:Eu phosphors prepared by spray pyrolysis

Starting from nitrate aqueous solutions with citrate acid and polyethylene glycol (PEG) as additives, YVO4:Eu phosphors were prepared by a two-step spray pyrolysis (SP) and citrate-gel (CG) methods, respectively. The morphology and luminescence properties of YVO4:Eu phosphors prepared from SP method were investigated by changing the concentration of precursor solution, the concentration of PEG and the annealing temperatures, respectively. The emission intensity of the phosphors increased with increasing the annealing temperature and solution concentration due to the increase of the crystallinity and particles size. Certain PEG concentration was necessary for obtaining solid spherical particles, and the optimum emission could be observed when the concentration of PEG was 0.02 g/ml. Compared with the spherical YVO4:Eu phosphors prepared by SP method, the CG-derived non-spherical YVO4:Eu phosphors showed lower emission intensity when annealed at 1000 and 1200 °C. The optimum concentration for the luminescence of Eu3+ is determined to be 7 mol % of Y3+ in YVO4 host.