Titanium dioxide thin films were deposited by Metallorganic Chemical Vapor Deposition at substrate temperatures ranging from 250 degrees C to 450 degrees C over soda lime glass and indium tin oxide coated glass substrates. X-ray diffraction studies show that films have a crystalline anatase structure at all the deposition temperatures. Particle size decreases and texture changes with the increase in substrate temperature. X-ray photoelectron spectroscopy confirms the appearance of a new well resolved state in the core level of Ti 2p spectrum shifted by 1.16 eV to lower binding energy due to the reduction of Ti+4 to Ti+3 upon litheation. Chronoamperometery, cyclic voltammetery and in situ UV-Vis spectrophotometeric studies were carried out on the prepared samples. Particle size and crystallinity control the electrochromic performance. The 350 degrees C film shows the highest ion storage capacity and the highest optical modulation along with an appreciable band gap broadening. (C) 2010 Elsevier B.V. All rights reserved.