A uniform titanium oxide film was grown on indium tin oxide/glass substrate with the aqueous solutions of ammonium hexafluoro-titanate and boric acid. The as-grown titanium oxide film shows good electrochromic characteristic because of fluorine passivation on defects and dangling bonds. The transmittance of as-grown titanium oxide on indium tin oxide/glass with a thickness of 270 nm is about 85% at the wavelength of 550 nm. After 50 times electrochromic cycling test, the transparency ratio is kept at 45% between fully colored state and fully bleached state at the wavelength of 550 nm. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3599637] All rights reserved.