Co-Investigator(Kenkyū-buntansha) |
ISHIDA Yutaka Nippon Paint Co., : Manager, 中央研究所, 課長
KATO Tamihiko Nagoya Institute of Technology : Lecturer, 工学部, 講師 (90024257)
KOBAYAKAWA Koichi Faculty of Engineering, Kanagawa University : Assistant, 工学部, 助手 (40078332)
SATO Yuichi Faculty of Engineering, Kanagawa University : Associate Professor, 工学部, 助教授 (20201535)
BABA Ryo Faculty of Engineering, University of Tokyo : Assistant, 工学部, 助手 (70198951)
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Research Abstract |
Photochromic materials, whose optical absorption properties change in response to light, are important for a number of technological applications. A stable, reusable photochromic thin-film could be used, for example, in optical displays and high-density memories. Thin films of some transition-metal oxides can be colored blue by band-gap excitation using ultraviolet light. For use with common semiconductor laser sources, however, photochromic materials are required that respond to visible light. Here we have investigated the preparation of visible-light-sensitive, reversibly photochromic films of MoO_3. Pretreated, vacuum-evaporated MoO_3 thin films were slightly blued by cathodic polarization in a non-aqueous electrolyte ; subsequent irradiation with visible light in air produced a strong colour enhancement. The photochromism could be erased by anodic polarization, and the coloration-decoloration process was repeatable over at least five cycles. The behaviour of these films contrasts with those blued by band-gap irradiation, which were not responsive to visible light.
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