Effect of tungsten oxide thin films deposited on cerium oxide nano rods for electrochromic applications

Abstract

Cerium oxide Nanorods were synthesized on Fluorine-doped Tin Oxide (FTO) coated glass substrate by hydrothermal process. Optimized Tungsten Oxide (WO3) films were coated on the top of cerium oxide (CeO2) Nanorods by a sputter deposition method. WO3 thin film was deposited at a constant substrate temperature of 300K under partial pressures of oxygen (ppo2) at 8 × 10−4 mbar. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV–Visible spectrometer, and cyclic voltammetry were used to analyse the films for material, optical, surface, and electrochemical properties. The improved CeO2/WO3 films increased the cathodic peak current which is related to their high active surface area and increased H+ ions intercalation in the films. In addition, the CeO2 Nanorods/WO3 hybrid films had a better electrochemical property in terms of the diffusion coefficient of 5.53 × 10−8 cm2/s. These structures produce considerable coloration efficiency when compared to pure WO3 (9.88, 10.19 and, 8.14 cm2/C at 700 nm). This study predicts that how varying concentrations of cerium oxide Nano rods change WO3 electrochemical behaviour which will help to choose the right rare earth elements and concentrations for energy-efficient smart windows.