Contrast, Switching Speed, and Durability of V[sub 2]O[sub 5]–TiO[sub 2] Film-Based Electrochromic Windows

Abstract

films as ion storage layers were proposed for electrochromic windows (ECWs) based on poly(3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine). films were fabricated by a sol-gel electrodeposition technique. The films were investigated by X-ray diffraction, a scanning probe microscope, and impedance spectroscopy. The cycling behaviors of the films were studied using cyclic voltammetry (CV) in /propylene carbonate solution. Electrochromism of the films upon intercalation was investigated by transmittance measurements during the CV process. The film-based ECW was successfully processed and studied. The ECW exhibited its high electrochromic contrast, rapid switching speed, and long-term cyclic stability. Its contrast was with a minimum transmittance, , at wavelength. The ECW took to reach a fully colored state from a fully bleached state. It took to go to a fully bleached state. The asymmetry of coloring and bleaching time was explained by modeling the ECW as a simple equivalent circuit. The cyclic durability of the ECW was tested over . It revealed the contrast degradation of only 2% at wavelength.