Doping-induced phase formations and luminescence of Eu3+-activated LaTiSbO6

Abstract

LaTiSbO6:xEu3+ (x = 0∼)1.0) phosphor with a typical PbSb2O6-related structure was prepared through a facile solid-state ceramic routine, and morphology measurements and structural Rietveld refinements were conducted. Results show that LaTiSbO6:xEu3+ (x = 0–0.4) phosphors formed a single trigonal phase (T-phase, space-group of P-31 m, No.162). The increase of Eu3+ doping (x = 0.5–0.6) can induce the formation of a second phase formation, that is, orthorhombic structure (O-phase) with space-group Pnma (No. 62). Meanwhile, heavily doped LaTiSbO6:xEu3+ (x = 0.6–1.0) was crystallized into a single orthorhombic structure (O-phase). LaTiSbO6 had a direct transition and the band gap was 2.97 eV. The luminescence properties of LaTiSbO6:xEu3+ (x = 0–1.0) were investigated at different doping levels. Eu3+-doping remarkably modified the band structure, resulting in the blue-shift of optical absorption, and the intrinsic blue emission of LaTiSbO6 peaked at 465 nm. Doping concentration exerted interesting influences on the optical properties of the phosphors, such as narrowed band gap, tunable red-emitting, dominant blue excitation wavelength, and thermal stability of the luminescence. Eu3+ ion was applied as a spectroscopic probe for the investigation of the relationship between luminescence and crystal microstructure.