1994 Fiscal Year Final Research Report Summary
Study on Fabrication of Intense Fluorescent Oxides doped with Rare Earths
| Project/Area Number |
05453073
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SHIMADA Masahiko Tohoku University, Institute for Advanced Materials Processing, Professor, 素材工学研究所, 教授 (80029701)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Tadashi Tohoku University, Faculty of Engineering.Professor, 工学部, 教授 (30176797)
TAKIZAWA Hirotsugu Tohoku University, Institute for Advanced Materials Processing, Research Associa, 素材工学研究所, 助手 (90226960)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Tantalates / Intense emission / Blue luminescence / Green luminescence / Red luminescence / Energy migration / Fluorescent rare earth solid solution oxides |
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| Research Abstract |
Fluorescent Oxides doped with rare earths such as Tm^<3+>, Tb^<3+> and Eu^<3+> have attracted much attention because of their blue, green and red luminescence. However, an enriched quantity of rare earths frequently leads to a quenching phenomenon in luminescence owing to the energy transfer between rare earth ions i. e. concentration quenching. It is important to elucidate the quenching mechanism in oxides in order to realize intense fluorescence. In the present study, the luminescence properties of Tm^<3+>, Tb^<3+> and Eu^<3+> in (La_<1-X>R_X) Ta_7O_<19> (R=Tm, Tb, Eu) solid solutions were examined systematically. X-ray diffraction patterns of the solid solutions indicated wat the crystal structure consisted of a network of (La^<3+>_<1-X>R^<3+>_X, Ta^<5+>)-O^<2-> polyhedra interstratified with a double layr of Ta^<5+> -O^<2-> polyhedra. According to the emission spectra, the most intense emissions were found near 460nm and X=0.14 in (La_<1-X>Tb_X) Ta_7 O_<19>, near 547nm and X=0.8 IN (La_<1-X> Tb_X) Ta_7O_<19>, near 610nm and X=1.0 in (La_<1-X>Eu_X)Ta_7O_<19>. As a results, a low dimensional arrangement of Tm^<3+>, Tb^<3+> or Eu^<3+> was much more preferable for getting intense emission, because it reduced the energy migration between rare earth ions in (La_<1-X>R_X) Ta_7O_<19> solid solutions.
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