Luminescence of Tm³⁺-doped YTa₇O₁₉

YTa₇O₁₉ doped with Tm³⁺ was prepared by a solid state reaction of co-decomposition nitrates as starting materials. The substitution of Tm³⁺ for Y³⁺ in Yi__xTm_xTa₇O₁₉ was performed in the full compositional region on calcinating at 1200°C for 24 24 in air. The solid solution was isomorphous of CeTa₇O₁₉ which involved a network of (Ce³⁺, Ta⁵⁺)-O^2- polyhedra inter-stratified in a double layer of Ta⁵⁺-O^2- polyhedra. The samples were identified by XRD and the optical measurement was carried out. According to the results of excitation and emission spectra, the intense blue emission of Tm³⁺ was observed near 460 nm corresponding to twice the intensity of YA10₃ doped with Tm³⁺. The unique concentration dependence of emission intensity in Y_1-zTm_zTa₇O₁₉ was observed. The maximum of relative intensity was obtained at x=0.2. This profile revealed the concentration quenching of emission. The energy migration of excited Tm³⁺ was discussed in relation to the low-dimensionality of substituting sites for Tm³⁺.