Spectroscopic study of the Tb3+→Eu3+ energy transfer process in TbAl3(BO3)4 doped with 1 % mol of Eu3+ in the 12–310 K temperature range

The Tb 3+ -to-Eu 3+ non-radiative energy transfer was studied through temperature-dependent luminescence spectroscopy (12−310 K), in TbAl 3 (BO 3 ) 4 crystals doped with 1 % mol Eu 3+ grown in a K 2 SO 4 -MoO 3 flux. Excitation and emission spectra were recorded and analyzed, along with the luminescence decay curves of the Tb 3+ emitting level ( 5 D 4 ). In the temperature range of 110–310 K, the decay curves were fitted using an adaptation of the Parent et al. model [20], where the Tb 3+ -to-Eu 3+ energy transfer process is described by the W parameter, representing the energy migration-assisted transfer. W (and thus the Tb 3+ -to-Eu 3+ transfer probability) decreases as temperature drops, reaching a plateau around 100 K. Below this temperature, the transfer probability remains relatively unaffected by further temperature reductions, likely due to the influence of non-regular Tb 3+ ions on the excited state dynamics of the 5 D 4 level.