B. Ohtani, Kunihiro Iwai, S. Nishimoto
Sep 1, 1994
Citations
0
Influential Citations
50
Citations
Journal
Journal of The Electrochemical Society
Abstract
Thin layers of niobium oxide (NbO[sub x]) were accumulated by the sol-gel process, with the sol of NbO[sub x] in ethanol prepared by partial hydrolysis of commercial niobium (V) ethoxide, on glass plates coated with transparent conducting tin oxide. Characterization by X-ray diffraction, differential thermal analysis, and thermogravimetry revealed that the as-prepared film, consisting of fully hydrated amorphous niobium(V) oxide, undergoes dehydration into the partially hydrated form and, finally, crystalline niobium(V) oxide (Nb[sub 2]O[sub 5]) by calcination at the temperature up to 873 K. The films exhibited electrochromic (EC) properties; the reversible color change was observed between colorless and brown-black by alternating anodic and cathodic polarizations, respectively. Among the films used in this study the crystalline Nb[sub 2]O[sub 5] film showed the best EC properties and its spectral change, durability for repeated coloration-decoloration cycles, and retentivity of colored states, i.e., memory characteristics under open-circuit conditions were investigated in detail.