Fig. 4: Temperature-dependent photoluminescence properties.

a Thermal ionization process in BLAGSO:Ce3+ and BLAGSO:Ce3+, Bi3+. b, c The corresponding temperature-dependent PL spectra of BLAGSO:0.05Ce3+ and BLAGSO:0.05Ce3+, 0.01Bi3+. d Temperature-dependent PL intensity ratios I(T)/I(Tinitial) of BLAGSO:0.05Ce3+ and BLAGSO:0.05Ce3+, 0.01Bi3+. e, f The relation between Ln[I(Tinitial)/I(T) – 1] and 1/kT for BLAGSO:0.05Ce3+ and BLAGSO:0.05Ce3+, 0.01Bi3+