Effect of different dopants on the long lasting phosphorescence behavior of CaTiO 3:Pr 3+

Abstract

In order to improve the luminescence properties of CaTiO 3:Pr 3+, a series of CaTiO 3:Pr 3+, such as CaTi 0.97Nb 0.03O 3:Pr 3+, Ca 0.8Zn 0.2TiO 3: Pr 3+, Ca 0.8Zn 0.2Ti 0.97Nb 0.03O 3:Pr 3+ and B 3+-doped Ca 0.8Zn 0.2Ti 0.97Nb 0.03O 3: Pr 3+ were prepared through conventional solid state reaction method. The results of the photoluminescence excitation and emission spectra showed that all the samples emitted red phosphorescence at 612 nm originating from 1D 2 to 3H 4 emission of Pr 3+ under the 337 nm excitation. When examined by the X-ray diffraction (XRD), all the samples presented a predominant phase of CaTiO 3 (JCPDS# 42-423) except Zn 2+-doped samples which also revealed another phase of Zn 2Ti 3O 8 (JCPDS# 73-579). The results of the afterglow decay curves showed that co-doping Zn 2+ ions, Nb 5+ ions or adding a small amount of B 3+ into Ca 0.8Zn 0.2Ti 0.97Nb 0.03O 3:Pr 3+ were effective in improving the photoluminescence properties of CaTiO 3:Pr 3+ phosphor. Thermoluminescence results showed that the trap existing in all the samples was the same as in CaTiO 3:Pr 3+ and doping singly Nb 5+ or Zn 2+ hardly changed the trap depth but co-doping Nb 5+ and Zn 2+ could modify the trapping level from 0.63 to 1.26 eV distinctively. In addition, adding a certain amount of B 3+ into CTO-PZN could also deepen the trap depth.