Premium
Prolonged lifetime of electrochromism of amorphous WO 3 –TiO 2 thin films
Author(s) -
Hashimoto Satoshi,
Matsuoka Hideki
Publication year - 1992
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740190187
Subject(s) - electrochromism , amorphous solid , lithium (medication) , materials science , x ray photoelectron spectroscopy , thin film , evaporation , vacuum evaporation , electrochromic devices , chemical engineering , analytical chemistry (journal) , crystallography , nanotechnology , chemistry , organic chemistry , electrode , thermodynamics , endocrinology , medicine , physics , engineering
The lifetime of the electrochromism of the WO 3 –TiO 2 films prepared by vacuum evaporation is found to exceed that of WO 3 films by a factor of five. X‐ray diffraction has revealed that the crystal structure of WO 3 –TiO 2 films stays amorphous, while crystalline compounds are formed in amorphous WO 3 films after colouring and bleaching. WO 3 –TiO 2 films stay amorphous after they are annealed at 400°C, although WO 3 films crystallize. SIMS and XPS analyses have revealed that half the amount of lithium injected during a colouring cycle is stored as OLi bonds in the bleached film. In WO 3 –TiO 2 films the number of bonds such as WOH and WO in which lithium ions accumulate is reduced. We conclude that the lifetime of the electrochromism is prolonged for amorphous WO 3 –TiO 2 films, because lithium does not accumulate and the WO 3 –TiO 2 films stay amorphous.