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2002 Fiscal Year Final Research Report Summary

Efficient phosphors for mercury-free fluorescent lamps

Research Project

Project/Area Number 12650817
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 工業物理化学
Research InstitutionTokyo University of Technology

Principal Investigator

YAMAMOTO Hajime  Tokyo University of Technology, School of Bionics, Professor, バイオニクス学部, 教授 (00247298)

Co-Investigator(Kenkyū-buntansha) OKAMOTO Shinji  Nara Institute of Science and Technology, Graduate School of Materials science, Assciate researcher, 物質創生科学科, 助手 (50324976)
MITA Yo  Tokyo University of Technology, Faculty of Engineering, Professor, 工学部, 教授 (20200040)
Project Period (FY) 2000 – 2002
KeywordsMercury-free lamp / Vacuum ultraviolet / Phosphor / Rare-earth ion / Quantum efficiency / Energy transfer / Non-linear luminescence
Research Abstract

[I]Efficient phosphors were surveyed to convert VUV light of 172nm wavelength obtained from Xe excimers to visible light. In 2001, we investigated feasibility of quantum cutting processes in stable oxides, specifically rare-earth orthophosphates. The results showed that nonradiatative relaxation from a high-energy excited level of a rare-earth ion and energy transfer between rare-earth ions in the UV region can reduce the probability of the quantum cutting. However, energy transfer from Pr3+ or Tm3+ to Gd3+ leads to efficient Gd3+ luminescence line at 312nm, which can be applied to lamps, which activate photoactive catalysis. This phenomena result from simple electronic configurations of Pr3+ or Tm3+, which have two 4f electrons or holes.
[II]In 2002, we investigated materials excited by energy transfer from a host to an activator ion.
(1)Substitution of Y by Gd in red-emitting YAIO3:Eu3+ gives rise to 30% increase in efficiency under 172nm light excitation. This remarkable effect result … More s from a red shift of the absorption edge of the host crystal by Gd substitution. We also developed a synthesis method to provide a single-phase material of high efficiency, which uses theta alumina as a starting material and firing temperature as high as 15000.
(2)In efficient red phosphor, SrTiO3:Pr3+, Al, energy is provided from the bound exciton to Pr3+.This work has shown that energy overlap between the fundamental absorption band of the host and 4f-5d absorption band of Pr3+ is correlated with the luminescence efficiency.
[III]Bright warm-white emission was discovered by cathode-ray excitation of rugged powder layers of insulater materials. This emission appears above the threshold electron-beam current and drastically increases in intensity with an increase in the beam-current density. The lowest threshold so far obtained is 0.02mA under 25kV electron excitation with a beam diameter of about 0.3mm. This emission may be a candidate of new non-mercury light source if the threshold can be further decreased. Less

  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] Y.Sato, S.Okamoto, P.Kumagai, H.Yamamoto, S.Tanaka: "Energy Transfer between Gd^<3+> and Other Rare earth Ions in the VUV region"Extended Abstracts, The 1^<st>" Int Conf On the Science and Technology of Emissive Displays and Lighting. 33-36 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Yamamoto, S.Okamoto, H.Kobayashi: "Luminescence of rare-earth ions in perovskite-type oxides from basic research to applications"Journal of Luminescence. 100. 325-332 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Okamoto, H.Yamamoto: "Emission from BaTiO_3 Pr^<3+> Controlled by Ionic Radius of Added Trivalent Ion"Journal of Applied Physics. 91(8). 5492-5494 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Okamoto, H.Yamamoto: "Luminescence properties of praseodymium-doped alkaline-earth titanates"Journal of Luminescence. 102-103. 586-589 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Yamamoto, M.Mikami, S.Nakamura: "Nonlinear cathodoluminescence from insulators"Journal of Luminescence. 102-103. 782-784 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 熊谷 高梓, 佐藤 裕二, 山元 明, 国本 崇: "紫外領域におけるGd^<3+>と他の希土類イオン間のエネルギー伝達"電子情報通信学会技術研究報告(TECHNICAL REPORT OF IEICE). 2001-124. 139-144 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Sato, T.Kumagai, S.Okamoto, H.Yamamoto, S.Tanaka: "Energy Transfer between Gd^<3+> and Other Rare earth Ions in GdPO_4 under Vacuum UV Excitation"Japanese Journal of Applied Physics. (to be published). (2004)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Sato, S.Okamoto, T.Kumagai, H.Yamamoto, S.Tanaka: "Energy Transfer between Gd3+ and Rare earth Ions in the VUV region"Extended Abstracts, The 1st Int.Conf.On the science and Technorogy of Emissive Displays and Lighting. 33-36 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Yamamoto, S.Okamoto, H.Kobayashi: "Luminescence of rare-earth ions in perovskite-type oxides : from basic research to applications"Journal of Luminescence. 100. 325-332 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Okamoto, H.Yamamoto: "Emission from BaTiO3:Pr3+ Controlled by Ionic Radius of Added Trivalent Ion"Journal of Applied Physics. 91[8]. 5492-5494 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Okamoto, H.Yamamoto: "Luminescence properties of praseodymium-doped alkaline-earth titanates"Journal of Luminescence. 102-103. 586-589 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Yamamoto, M.MIkami, S.Nakamura: "Nonlinear cathodoluminescence from insulators"Journal of Luminescence. 102-103. 782-784 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] 熊谷 高梓, 佐藤 裕二, 山元 明, 国本 崇: "紫外領域におけるGd3+と他の希土類イオン間のエネルギー伝達"電子情報通信学会技術研究報告 (TECHNICAL REPORT OF IEICE). 2001-124. 139-144 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Sato, T.Kumagai, S.Okamoto, H.Yamamoto, S.Tanaka: "Energy Transfer between Gd3+ and Other Rare earth Ions in GdP04 under Vacuum UV Excitation"Japanese Journal of Applied Physics. (to be published). (2004)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2005-04-19  

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