Characterization and luminescence properties of sol-gel derived M′-type LuTaO4:Ln3+ (Ln = Pr, Sm, Dy) phosphors

M'-type Lu(1-x)Ln(x)TaO(4) (Ln = Pr, Sm, Dy) phosphors have been successfully synthesized by sol-gel technique, their crystallization, morphology, photoluminescence and X-ray excited luminescence properties were investigated in detail. The phosphors had good crystallization behavior. The optimum doping concentrations of Pr3+, Sm3+ and Dy3+ in LuTaO4 were at x = 0.003, 0.025, 0.02, respectively. They exhibited a more efficient host excitation relative to the 4f-4f excitations of the rare-earth ions, and a dominant D-1(2) -> H-3(4),(4)G(5/2) -> H-6(7/2) or F-4(9/2) -> H-6(13/2) emission for Pr3+, Sm3+ or Dy3+, respectively, which corresponds to the average decay time of 21.7, 745.7 or 10.0 mu s, respectively. It is expected that Pr3+- or Dy3+-doped LuTaO4 phosphors with a microsecond level decay time are very encouraging for applications in X-ray computerized tomographic imaging with high spatial resolution. (C) 2014 Elsevier Ltd. All rights reserved.