| Project/Area Number |
14550037
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Gifu University2002 |
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Principal Investigator |
YAMAGA Mitsuo Gifu University, Department of Mathematical and Design Engineering, Professor, 工学部, 教授 (90159202)
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| Co-Investigator(Kenkyū-buntansha) |
KODAMA Nobuhiro Akita University, Department of Materials Science and Engineering, Professor, 工学資源学部, 教授 (90282152)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | long-lasting phosphorescence / Optical energy storage materials / Barium silicate crystals / Rare earth ions / Europium ions / electron-hole recombination / Self-trapped holes / Color centers / 長残光 / バリウムケイ酸塩結晶 / メリライト結晶 |
|---|
| Research Abstract |
UV or visible excitation for Eu^<2+:>Ba_2SiO_4 and Eu^<2+:>\Bs_3SiO_5 crystals produces broadband luminescence with peak wavelengths of 510 and 590 nm, respectively. The intensities of the long-lasting phosphorescence were measured as functions of temperature and time. The radiative decay times are distributed in the wide range of 1-10^3 seconds besides the Eu^<2+> fluorescence lifetime of 10^6 seconds. The decay curves above one second in the temperature range of 100-500 K fit t^n(n〜1). The temperature dependence of the long-lasting phosphorescene intensities integrated, in a time domain. obeys the modified Arrhenius's equation. with thermal activation energies including radiative and nonradiative decay processes. These results suggest that electrons and holes produced by UV or visible excitation move back to Eu2+ sites in the crystals through thermal hopping and/or tunneling and recombine radiatively at Eu^<2+>.
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