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The electrochromic films featuring the well dispersed ITO nanocrystal (about 10 nm) in amorphous WO 3 (ITO@WO 3 ) have been successfully fabricated with a solution process. The structure and electrochromic properties of the as-prepared films were studied by high resolution transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction, and electrochemical methods. The measured coloration/bleach time decreases from 10.5/27.8 s to 5.7/0.9 s with the increasing of ITO/AMT ratio indicating that embedded ITO nanocrystals induce the nanocrystal/glassy interface effect remarkably improving the ion diffusion coefficient and electrochemical activity. The optimal T at 633 nm of 0.1 ITO@WO 3 films is about 53.80% much higher than that of pure WO 3 (about 42.09%). But in near-infrared (NIR) range the pure WO 3 films show the best transmittance modulation rather than the composite films. The above stated results are indicative that the interface effects of embedded ITO nanocrystals play the key role while its plasmon-induced electrochromic effects are limited because of not only excellent NIR modulation capability of amorphous WO 3 itself but also the relative large size of ITO nanocrystals used, demonstrating that smaller nanocrystal size (∼5 nm) are required for better electrochromic performance of the composite films.

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Transparent electrochromic nickel oxide films with Ni-rGO (reduced graphene oxide) co-doping were deposited on ITO substrates by a facial sol-gel method. The structure characterization of the composite film was carried out by XRD, SEM and TEM, and proposed the growth model to illustrate the fabrication process. The electrochromic properties of Ni/NiO/rGO films have been studied in 1 mol/L KOH aqueous electrolyte via cyclic voltammetry, chronoamperometry and visible light transmission. The optimum Ni/NiO/rGO composite films with a thickness about 80 nm exhibits the maximum anodic/cathodic diffusion coefficient of 6.28 × 10 −9 cm 2 • s −1 /4.94 × 10 −9 cm 2 • s −1 and outstanding electrochromic properties, including the stable and reversible coloration-bleaching cycles, and large coloration efficiency (48.15 cm 2 • C −1 ), as well as large transmittance modulation (51.6%) and fast coloration/bleaching response speed (4.2 s/2.4 s) at a wavelength of 550 nm. These characteristics open the possibility to the industrial applications, particularly for the large-area electrochromic devices.