Enhancement of Photoluminescence in (Gd,Eu)_2O(WO_4)_2 Phosphors by Lanthanum Doping into the Host Gd_2O(WO_4)_2 Lattice

摘要

Red-emitting (Gd_(1-x-y)La_xEu_y)_2O(WO_4) (0 ≤ x ≤ 0.05, 0.30 ≤ y ≤ 0.50) phosphors were synthesized by the conventional solid state reaction method. Single phase gadolinium oxytungstate phosphors with high crystallinity and monoclinic structure were obtained, exhibiting excellent luminescence efficiency under excitation at wavelengths of 394 and 464 nm. The luminescence emission intensities of these phosphors were successfully enhanced by La~(3+) doping into the host Gd_2O(WO_4)_2 lattice. The highest emission intensity was obtained for (Gd_(0.56)La_(0.04)Eu_(0.40))_2O(WO_4)_2, of which the emission intensities were 18.9 and 37.0 times higher than those of a commercial (Y_(0.98)Eu_(0.02))_2O_2S phosphor under excitation at 394 and 464 nm, respectively.