Luminescence and energy transfer processes in Ce3+ activated (Gd,Tb)3Al5O12 single crystalline films.

The luminescence and scintillation properties of gadolinium terbium aluminium garnet single crystalline films, Gd 3−x Tb x Al 5 O 12 , doped with Ce 3+ are investigated as a function of the Gd/Tb ratio with the aim of an improved understanding of the energy transfer processes between Ce 3+ and Tb 3+ ions in the aluminium garnet hosts. Upon replacing the Gd 3+ by Tb 3+ , the crystal field splitting for the 5d energy level of Ce 3+ does not change significantly, due to comparable sizes of the Gd 3+ and Tb 3+ cations. Temperature dependence of the decay time of Tb 3+ and Ce 3+ luminescence confirms an efficient energy transfer from the Tb 3+ to Ce 3+ and provides a qualitative understanding of this process. Furthermore, bidirectional energy transfer processes between the Ce 3+ and Tb 3+ are revealed. Scintillation decays under α-particles excitation show the presence of the fast and slow sub-microsecond components. [ABSTRACT FROM AUTHOR]