Electrochromic characteristics of a nickel borate thin film investigated by in situ XAFS and UV/vis spectroscopy

Masaaki Yoshida, Tsuyoshi Iida, Takehiro Mineo, Takumi Yomogida, Kiyofumi Nitta, Kazuo Kato, Hiroaki Nitani, Hitoshi Abe, Tomoya Uruga, Hiroshi Kondoh

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The electrochromic transition of a nickel borate thin film between colorless and brown was examined by means of in situ XAFS and UV/vis spectroscopy. The XAFS spectra showed that the average valence state of the nickel species in the film changed from +2.1 to +3.8 following the application of an electrode potential. Additionally, a broad peak at 700nm was observed during in situ UV/vis absorption measurements on the application of a positive potential. These results suggest that the nickel borate film reversibly forms a NiOOH structure with a domain size of several nanometers during the electrochromic reaction.

Original languageEnglish
Pages (from-to)355-358
Number of pages4
Issue number5
Publication statusPublished - 2014



  • Electrochromism
  • In situ measurement
  • Nickel borate
  • X-ray absorption spectroscopy

ASJC Scopus subject areas

  • Electrochemistry

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