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 Tb3+-to-Eu3+ non-radiative energy transfer was studied through temperature-dependent luminescence spectroscopy (12-310 K), in TbAl3(BO3)(4) crystals doped with 1 % mol Eu3+ grown in a K2SO4-MoO3 flux. Excitation and emission spectra were recorded and analyzed, along with the luminescence decay curves of the Tb3+ emitting level (D-5(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 Tb3+-to-Eu3+ energy transfer process is described by the W parameter, representing the energy migration-assisted transfer. W (and thus the Tb3+-to-Eu3+ 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 Tb3+ ions on the excited state dynamics of the D-5(4) level.