Low-temperature VUV photoluminescence and thermoluminescence of UV excited afterglow phosphor Sr3AlxSi1−xO5:Ce3+,Ln3+ (Ln = Er, Nd, Sm, Dy and Tm)

Abstract

Low-temperature (10 K) photoluminescence excitation and emission spectra of undoped Sr₃SiO₅ as well as Ce³⁺ and Eu³⁺ single doped Sr₃SiO₅ have been investigated. They show the host exciton band and the O²⁻ to Eu³⁺ charge transfer band at 5.98 eV (207 nm) and 3.87 eV (320 nm) respectively. Low-temperature thermoluminescence measurements are reported for Ce³⁺ and lanthanide (Er, Nd, Sm, Dy, Er and Tm) co-doped Sr₃Al_xSi_1−xO₅. The results show that Ce³⁺ is the recombination centre and Nd, Sm, Dy and Tm work as electron traps with trap depths of 0.95 eV, 1.89 eV, 1.02 eV, and 1.19 eV, respectively. Thermoluminescence excitation spectra of Sr_2.98Al_0.02Si_0.98O₅:0.01Ce³⁺,0.01Dy³⁺ show that the traps can be charged by 260 nm UV excitation.