Open AccessElectrochromic effect of nanostructured WO3 bulk
Author(s) -
Yang Xin-Sheng,
Weichao Yu,
Dong Liang,
Feng Zhang,
Qi Li-Zhen
Publication year - 2004
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.53.2724
Subject(s) - electrochromism , materials science , tungsten , valence (chemistry) , x ray photoelectron spectroscopy , ion , anode , tungsten trioxide , colored , chemical physics , nuclear magnetic resonance , electrode , chemistry , physics , organic chemistry , metallurgy , composite material
WO3 films are well known for the change of their color through electro, photo and thermochromism. We report here that the nanostructured WO3 bulk has an obvious electrochromic effect, which does not exist in ordinary WO3 bulk. The sample turns to a deep blue color upon changing from anode to cathode when external voltage is applied. There is no difference of the microstructure and phase structure between the colored and uncolored samples. X-ray photoelectron spectroscopy analysis shows that low valence state of tungsten ion (W5+) existed in the colored samples. Based on the experimental results, it is concluded that the coloration is an electron-injection effect. The high valence state of tungsten ion (W6+) in nanostructured WO3 bulk has enough activity to combine with electron and turns to the low valence state counterpart because of the surface effects of nanostructured materials. As a consequence, the sample changes its color.