Dynamic Coloration Properties of Spin-coated WO_3 Thin Films

WO3 thin films were fabricated on ITO glass substrates by the spin-coating technique usingH2WO4 and H2O2 as precursors. The films annealed at 150℃ for 1h show dynamic colorationand bleaching efficiencies of 10.0, 8.6 cm2/C respectively at 633um during cycling between --1 and+1V (vs. SCE) in LiClO4/PC at the scan rate of 20mV/s. The films annealed at 350℃ showimproved cycling stability while losing some efficiency. The films annealed at 150 ℃ have also beenelectrochemically cycled by a constant current charge injection, which is found to be more easy tocontrol the amount of charge injected into the films, and avoid overcharging the films, especiallythe surface layer.