Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO) and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101) plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600？nm fiber diameter and nanocrystalline having size 40？nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3. 1. Introduction The electrochromism is key to green technology as it controls the energy of solar flux entering in building, utilizes solar energy, and increases comfort in buildings. Electrochromic materials are able to sustain reversible and persistent changes of their optical properties under the action of a voltage. The electrochromic phenomenon was discovered in tungsten oxide [1] and this material remains the most promising candidate for large-scale uses of electrochromic devices. Their potential applications include several technological areas, such as smart windows, self-dimming rear mirror, electrochromic display, and antiglare rear view mirrors of automobiles [2]. Among a variety of the transition metal oxides, tungsten oxide (WO3-x) is found to be the most efficient candidate for electrochromic applications. Granqvist [3] explains the theoretical explanation of electrochromic mechanism and reviews about different nanostructured oxides for electrochromic device and describes the mass fabrication by electrochromic foil technology. The electrochromic performance of tungsten oxide, reversible coloration under double injection of ions and electrons, strongly depends on its nature and microstructure. Nanoscale microstructure could improve the electrochromic performances of tungsten oxide thin film because it is easy for ion to intercalate and deintercalate in thin film. Mesoporous tungsten oxides exhibit superior high-rate ion-insertion performance for their short-diffusion length of lithium and hydrogen ions into electrochromic films [4]. Several researchers have attempted to employ the concept of nanotechnology to improve the drawbacks of thin-film-based electrochromic devices (ECDs) such as contrast, cycling life stability, and slow switching time between the colored and bleached states. The researcher developed transition metal oxide nanowires