Site dependent thermoluminescence of long persistent phosphorescence of BaAl2O4: Ce 3+, Opt

Abstract A very long persistent phosphor BaAl 2 O 4 : Ce 3þ was prepared and studied. The Ce 3þ 5d-4f emissions from two Ba 2þ sites in the BaAl 2 O 4 were observed at 450 and 402 nm. The lowest 4f-5d excitation peaks were recorded at 357 and 335 nm, respectively. The persistence times of the long afterglow emissions from Ce 3þ at the two sites were found to be longer than 10 h. Site-selective thermoluminescence spectra of the sample were measured. Two sets of thermoluminescence peaks were detected at )43, )26 and 27°C, and )53, )36 and 30°C (heating rate 13.3°C/min) corresponding to the two sites at 450 nm (site-1) and 402 nm (site-2), respectively. Dy 3þ , Ce 3þ co-doped samples were also prepared, which introduce new defect-related traps at 18, 50, and 82°C (heating rate 10°C/min). These defect-related traps due to Dy 3þ co-doping also contribute to the Ce 3þ afterglow at the two sites.