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Thin films of nickel oxide were deposited with different thicknesses in a mixed atmosphere of O₂ and Ar gases from a high purity target of 99.99% nickel using the reactive DC-sputtering technique. The same amount of the Pt-catalyst was sputtered from a high purity target of 99.99% platinum in Ar atmosphere onto the top of nickel oxide films with different thicknesses. The gasochromic behavior of the films was investigated. The optical response was measured for the as-deposited and for the intercalated films with hydrogen ions. The change of the transmission resulting from the ion insertion in the films was calculated in the visible and the near infrared regions. The fundamental optical energy gap was determined and studied as a function of the film thickness and the time of ion intercalation.

The NiO nanocrystalline/reduced graphene oxide (rGO) composite film was successfully synthesized using a simple hot-injection and dip coating method. The as-prepared samples were characterized using X-ray diffraction (XRD), Raman, scanning electron microscope (SEM), ultraviolet and visible spectrophotometer (UV). Compared to the NiO film, the NiO nanocrystalline/rGO composite film exhibits enhanced electrochromic properties and large $\mathrm{\Delta }T$ (40.7% at 550nm), fast switching speed ($t_c=4$.3s and $t_b=3$.9s), high coloration efficiency (12.85cm² C${}^{-1})$ and better cycling performance (1000 cycles). The improvement of the electrochromic properties was attributed to the large specific surface area and good conductivity of the rGO.

WO₃/Cu composite film electrodes were synthesized by hydrothermal combined electrodeposition method. Characterization of samples was conducted by SEM, XRD and XPS, which showed WO₃/Cu composite films had been synthesized. The diffusion coefficient, reversibility, response time, coloration efficiency and transmission rate of the samples were obtained by electrochemical and spectral measurements. The photocurrent and photoelectric catalysis degradation efficiency of the samples were obtained by photocurrent and photoelectric catalysis measurements. The WO₃/Cu composite films improve electrochromic performance, photocurrent and photoelectric catalytic activity compared with pure WO₃ nanoblocks, and the WO₃/Cu composite film obtained by depositing Cu nanoparticles at 50 s shows the highest electrochromic performance, photocurrent and photoelectric catalytic activity. Meanwhile, the direct photocatalytic and electric catalytic activity of the composite film are also discussed. The combined effects of the lower band gap and the Schottky junction lead to significant enhancement in the electrochromic and photoelectrochemical properties of the WO₃/Cu composite film.

Electrochromic (EC) materials have been widely studied in energy-saving smart windows due to their reversible control of optical performance under electric fields. Novel tungsten oxide-poly (3, 4-ethylenedioxythiophene) (WO₃-PEDOT) core–shell inverse opal (IO) films are obtained by electrochemical polymerization of PEDOT onto WO₃ IO templates. The WO₃ IO templates are prepared through the electrodeposition of WO₃ into the voids of a polystyrene (PS) colloidal crystal, followed by calcination to remove the polystyrene microspheres. The designed microstructure and chemical composition of the WO₃-PEDOT IO films are determined by SEM, XRD, XPS and Raman spectroscopy. The WO₃-PEDOT IO films exhibit promising optical contrast ($\sim$52% at 600 nm and $\sim$77% at 1020 nm), indicating their bifunctional potentials in both visible and near infrared (NIR) region modulation. The WO₃-PEDOT IO films also show excellent EC properties of much shorter response time (6.7 s for coloring and 5.8 s for bleaching) and superior cycling stability than that of the bare WO₃ IO. These results suggest that the synergistic effect between the WO₃ IO core and PEDOT shell may greatly increase the electrolyte accessibility to active sites and improve the interaction between the inorganic/organic interfaces to obtain enhanced EC performance.

Studies were carried out on gel electrolytes based on PMMA and non-aqueous solution of lithium salt, LiClO₄ in the mixed solvent of propylene carbonate and ethylene carbonate (PC+EC). This paper reports the influences of polymer concentration and ratios of mixed solvent on the properties of gel electrolytes. The addition of polymer has increased the viscosity considerably without affecting the stable potential window, resulting in thermally stable gels. Result shows that addition of EC increases the conductivity by two order of magnitude as compared to that of PC alone. However conductivity decreases with addition of EC beyond 2:1 ratio of EC:PC. These gel electrolytes showed good room temperature conductivity in the order of 10^-3 S/cm with high transmission in the visible region. This makes the gel a very promising electrolyte candidate for electrochromic device application.

Titanium dioxide (TiO₂) thin films were prepared by using sol-gel dip coating technique. The coating solutions were prepared by reacting titanium isopropoxide as precursors and ethanol as solvent. The films were formed on transparent ITO-coated glass by a dip coating technique and final dried at various temperatures up to 600 °C for 30 minutes. The films were characterized with the UV-Vis-NIR Spectrometer, Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). XRD results show that the films dried at 600 °C form anatase structure. From the spectroscopic studies, the sample shows electrochromic property.

Electrochromic(EC) coatings, thin films that change their optical absorptance as a function of injected ions (typically H⁺ or Li⁺ species), is an area of research and development that has received attention from academia, industry and government laboratories. In this paper a new hydrogenation technology and its fabrication process are put forward, the study on the resistivity, surface morphology, the crystal analysis, and the electrochromic properties is also performed, thus the optimum process is defined. In doing that, there is an important meaning for preparing the all-solid electrochromic devices.