期刊
JOURNAL OF LUMINESCENCE
卷 181, 期 -, 页码 277-285出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jlumin.2016.09.025
关键词
Scintillation; Pr4+; Luminescence; Codoping; Lutetium-aluminum garnet
类别
资金
- Czech Science Foundation (GACR) [15-18300Y]
- Japan Science and Technology Agency (JST)
- Ministry of Health Labor and Welfare
- New Energy and Industrial Technology Development Organization (NEDO)
- Ministry of Economy, Trade and Industry (METI)
- Association for the Progress of New Chemical Technology
- Japan Society for the Promotion of Science (JSPS)
- Adaptable and Seamless Technology Transfer Program through Target-driven RD (A-STEP), JST
- Ministry of Education, Youth and Sports of Czech Republic [LM2015088, LO1409]
- European Union [644260]
The influence of the Mgt(2+) codoping and annealing in the air on the scintillation and luminescence characteristics of Pr-doped lutetium-aluminum garnet crystals (LuAG) was studied to find a possible positive effect of Pr4+ The overall scintillation efficiency under X-ray excitation of the annealed Pr-doped samples decreased with increasing Mg concentration. This was explained by increased overlap of the Pr3+ 5d-4f emission with the charge-transfer (CT) absorption band of the Pro(4+) ion stabilized by Mg2+. This absorption caused even greater decrease of the light yield, as the light is collected from the whole sample volume in the pulse-height spectrum measurement. Electron centers based on oxygen vacancies (F+ centers) which can have negative influence on scintillation mechanism were revealed by the electron paramagnetic resonance (EPR) experiments. The O- hole center was detected as well and the temperature dependences of the EPR spectra showed that its thermal stability was decreased by Mg codoping. Negligible changes in the decay time of Pr3+ 5d-4f photoluminescence exclude the non radiative energy transfer from relaxed 5d(1) excited state of Pr3+ towards CT absorption transition of Pr4+ and suggest that simple reabsorption of the emitted light takes place. Unlike for the Ce-doped analogs, promoting the Pr3+ luminescence center to the tetravalent state by divalent ion co-doping and air annealing did not improve scintillation properties of Pr-doped LuAG. (C) 2016 Elsevier B.V. All rights reserved.
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