Tailoring scintillation and luminescence through Co-doping engineering: A comparative study of Ce,Tb Co-doped YAGG and GAGG garnet crystals
Kazuya Omuro, Masao Yoshino, Karol Bartosiewicz, Takahiko Horiai, Rikito Murakami, Kyoung Jin Kim, Kei Kamada, Romana Kučerková, Vladimír Babin, M. Nikl, Akihiro Yamaji, Takashi Hanada, Yuui Yokota, Shunsuke Kurosawa, Yūji Ohashi, Hiroki Sato, Akira Yoshikawa
Abstract
The development of scintillators with co-doping mechanisms has received significant attention due to the resulting enhancements in luminescence and scintillation properties. Scintillators such as Ce-doped (Gd,Tb) 3 (Al,Ga) 5 O 12 have been recognized for their improved performance, attributed to the effective energy transfer between Ce 3+ and Tb 3+ ions. Nevertheless, the presence of Gd 3+ introduced complexities, as its absorption lines strongly overlap with those of Tb 3+ , thus masking the details of mechanisms of the Tb 3+ ↔Ce 3+ energy transfer. This study endeavored to elucidate this mechanism by comparing the luminescence characteristics of Ce,Tb co-doped Y 3 Al 2 Ga 3 O 12 (YAGG) and Gd 3 A 2 Ga 3 O 12 (GAGG) single crystals . Through detailed photoluminescence spectral analysis, it was discerned that GAGG exhibited a more robust Tb 3+ ↔Ce 3+ energy transfer, as evidenced by a marked extension in the decay time of Ce 3+ luminescence. Furthermore, GAGG demonstrated superior integrated radioluminescence intensity across all compositions which is a result of efficient energy transfer from Gd 3+ to the luminescence centers. Additionally, comparative thermally stimulated luminescence glow curves, revealed distinctive spectral features between YAGG and GAGG, underscoring the complexity of their luminescence mechanisms. This comparative study not only augmented our comprehension of the intricate energy transfer processes in Ce, Tb co-doped garnet scintillators but also underscored the potential for tailored scintillator development through strategic ion co-doping.