Doping effects of Nb⁵⁺ on red long afterglow phosphor CaTiO₃:Pr³⁺

A series of Nb⁵⁺ codoped red long afterglow phosphors CaTi_1-xNb_xO₃:Pr _0.002³⁺ (0 ≤ x ≤ 0.05) is prepared by a solid state reaction method. Their photoluminescence, phosphorescence and thermoluminescence are investigated. The results indicate that codoping Nb⁵⁺ can improve the photoluminescence and phosphorescence property of CaTiO₃:Pr³⁺ significantly. When 3-mol% Nb⁵⁺ is codoped, the emission intensity of CaTiO₃:Pr³⁺ is enhanced twice, while the afterglow time is extended from 10 min to about 40 min. Thermoluminescence results reveal that the trapping level of CaTiO₃:Pr³⁺ is reduced from 0.82 eV to 0.62 eV by codoping Nb⁵⁺. The effect of Nb⁵⁺ doping on enhancing the photoluminescence intensity and afterglow time of CaTiO₃:Pr³⁺ is discussed.