1. Insights into luminescence and energy transfer processes in Ce3+- and Tb3+ co-doped (Gd, Y)3Al2Ga3O12 garnet single crystals.
- Author
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Omuro, Kazuya, Yoshino, Masao, Bartosiewicz, Karol, Horiai, Takahiko, Murakami, Rikito, Kim, Kyoung Jin, Kamada, Kei, Kucerkova, Romana, Babin, Vladimir, Nikl, Martin, Yamaji, Akihiro, Hanada, Takashi, Yokota, Yuui, Kurosawa, Shunsuke, Ohashi, Yuji, Sato, Hiroki, and Yoshikawa, Akira
- Subjects
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ENERGY transfer , *SINGLE crystals , *DOPING agents (Chemistry) , *LUMINESCENCE , *GARNET , *X-ray imaging - Abstract
Driven by the pursuit of optimizing the luminescent properties of garnet-based single crystals for X-ray imaging applications, this work reports on the successful synthesis and in-depth characterization of GYAGG crystals doped with Ce³⁺ or Tb³⁺ ions, and doubly-doped with both of them. Micro-pulling down synthesis yielded crystals with a single cubic phase confirmed by X-ray diffraction. Photoluminescence (PL) and radioluminescence (RL) measurements on Ce³⁺,Tb³⁺ co-doped GYAGG revealed bidirectional energy transfer processes. Characteristic broadband 5d 1 →4f emission of Ce³⁺ centers peaking at 530 nm and narrow 4f→4f emission lines of Tb³⁺ ions starting from 5D 4 level within 480–630 nm were observed. At higher doping levels, cross-relaxation in Tb³⁺ pairs resulted depleted 5D 3 state and only the emission from 5D 4 one was observed in the spectra. Analysis of PL decay characteristics corroborated the spectral observations, confirming progressively decreasing Ce³⁺ decay time (down to 40 ns at 15 % Tb3+) due to enhanced Ce³⁺→Tb³⁺ energy transfer. Similarly, the Tb³⁺ decay time accelerated by more than 60 % after the Ce³⁺ co-doping. Notably, co-doping with 0.5 % Ce³⁺ and 10–15 % Tb³⁺ doubled the luminescence intensity of RL spectra compared to 0.5 % Ce³⁺-doping alone, attributed to the increased density of emitting centers. • High-quality and crack-free GYAGG:Ce,Tb single crystals were successfully grown. • The photoluminescence spectra revealed Ce³⁺↔Tb³⁺ bidirectional energy transfer. • At lower Tb³⁺ doping (0.5 %), the bidirectional energy transfer was inefficient. • High Tb³⁺ doping (15 %) significantly enhanced energy transfer. • Co-doping yielded a two-fold radioluminescence intensity compared to sole doping. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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