“Propriedades Eletrocrômicas de Filmes Finos de WO3, WO3:Li+ eWO3:Li+ :TiO2”.

Abstract

This work studies thin film of tungsten oxide (WO3), tungsten oxide doped with lithium salt (WO3: Li+ ) and tungsten oxide-doped lithium salt and titanium (WO3: Li+ :TiO2) prepared by the sol-gel process. The sols were obtained by the using metallic tungsten, lithium salt (LiCF3SO3) and titanium alkoxide (titanium isopropoxide) as precursors, ethanol as solvent and glacial acetic acid as catalyst. The films were prepared by dip-coating technique on a substrate (FTOPilkington Glass). There were a systematic study to obtain films with the desired electrochemical properties. The films deposited after rapid hydrolysis in air and were submitted to a heat treatment at 240°C for 1 hour. Thin films of WO3 and WO3 doped were studied by different electrochemical techniques such as chronoamperometry, cyclic voltammetry, electrochemical impedance measurements and optical measurements (UV-Vis) to study the insertion/extraction process. X-ray measurements were performed in order to study the crystalline or amorphous character of the films. To study the morphology of the films were measured by scanning electron microscopy(SEM) and atomic force microscopy(AFM). The goal of this project is to prepare and characterize thin films, which will be part of a working electrode electrochromic device, in order to obtain satisfactory electrochromic properties.