Thermoluminescence and persistence luminescence of barium aluminate (BaAl2O4) and Eu doped BaAl2O4 phosphors: a preliminary study

Thermoluminescence (TL) and persistence luminescence (PerL) are two luminescence emission phenomena associated with trapping and subsequent release of charge carriers in various point defects in a crystal. We report preliminary results of TL and PerL of an undoped BaAl2O4 and a 2% Eu doped BaAl2O4 phosphor synthesized using a solution combustion method. Surface morphological analysis suggests that the average grain size of the undoped sample is ~ 60.67 nm whereas that of the doped sample is ~ 53.45 nm. A TL glow curve of the undoped sample recorded at 1 oC/s following 260 nm UV-C irradiation for 15 min shows a weak TL glow peak at ~ 102 oC. On the other hand, the doped sample under identical measurement conditions shows a high intensity glow peak at ~ 184 oC. For both samples, the peak intensity was found to increase sublinearly with irradiation time. Under the UV-C irradiation, both samples show PerL for more than 1 h. The intensity of PerL of the undoped sample is found to be weaker than that of the doped one. This study reveals that the undoped BaAl2O4 sample has intrinsic electron traps which help to persist luminescence in BaAl2O4. This preliminary study also reveals that the intensities of TL and PerL in BaAl2O4 can be enhanced by doping of Eu.