Synthesis and photoluminescence properties of La2O2SO4 : Eu3+ quasi-spherical phosphors were investigated by homogeneous precipitation from La(NO3)(3), Eu(NO3)(3), (NH4)(2)SO4 and urea ((CO(NH2)(2)) as the starting materials. It was found that the yield of the precursor is strongly dependent on m value, namely, the molar ratio of urea to La(NO3)(3), and the optimal m value is 10. Thermal analysis, FT-IR and XRD show the optimal precursor is composed of La-2(OH)(2)CO3SO4 center dot 2H(2)O and can be converted into pure La2O2SO4 phase at a temperature higher than 600 degrees C for 1 h in air. SEM observation shows that the obtained La2O2SO4 phosphor particles are quasi-spherical in shape and narrow distribution with a mean particle size of about 2 mu m. Photoluminescence spectra reveal that the emission intensities of the La2O2SO4 : Eu3+ phosphors depend on the calcination temperature and the strongest emission peak is located at 620 nm under 280 nm UV light excitation for the La2O2SO4 : Eu3+ phosphors calcined at 1000 degrees C, which corresponds to the D-5(0) -> F-7(2) transition of Eu3+ ions. The quenching concentration of Eu 3+ ions is 5 mol% and the concentration quenching mechanism is the electric dipole-quadrupole interaction for the D-5(0) -> F-7(2) transition of Eu3+ ions.

Keywords: Luminescent materials; Rare earth oxysulfate; Homogeneous precipitation synthesis; Photoluminescence