Chih-Ming Wang

Effect of Deposition Temperature on the Electrochromic Properties of Electron Beam-Evaporated WO3 Thin Films

Tungsten oxide (WO3) thin films were deposited on ITO/glass substrates using the electron beam evaporation technique. The WO3 films were grown on substrates at temperatures varying from room temperature (RT) to 240 °C. The structural characterization and surface morphology were examined using X-ray diffraction (XRD) and a field emission scanning electron microscope (FE-SEM). The electrochromic properties of WO3 thin films were investigated using cyclic voltammograms (CVs) and in situ transmittance measurements, which were performed on WO3 thin films immersed in an electrolyte of 1 M LiClO4 in propylene carbonate (PC). An amorphous 510-nm-thick WO3 film heated at RT exhibits the maximum transmittance variation (ΔT%) of 61.8% between the bleached state and the colored state, with a ΔOD of 0.739, Q of 17.31 mC/cm2 and η of 42.69 cm2/C at a wavelength (λ) of 550 nm.

Electrochromic Properties of Nano-Columnar Nickel Oxide

Electrochromic properties of transition metal oxides had much attention in recent years. The electrochromic thin films can be assembly as electrochromic devices (ECDs) and then used for applications in devices such as mirrors, panels and smart windows. A kind of complementary ECD is popular in resent years. Therefore, a specific investigation on nickel oxide (NiO) electrochromic properties is completed in this study. The crystalline structure of the NiO films was analyzed using XRD (PANalytical X’Pert PRO) with Cu-Kα radiation. The atmosphere of oxygen concentration increasing has changed the NiO films crystalline from (200) to (111). The thicknesses and surface microstructures of the NiO films were investigated using a scanning electron microscope (SEM, Philips/FEI XL40 FEG). It is observed that films are relatively smooth deposited without oxygen. The characterization of the electrochromic properties was carried out in a two-electrode cell with an electrochemical analyzer (CHI 611B). The NiOx changes the transmittance of NiO films in the wavelength range of 300-1500 nm and the color of the film changes from transparent to brown. The nano-crack exhibits in the NiO film did enhance the electrochromic properties.

Electrophoretic Deposition of TiO2 Films on Metal Mesh for Dye-Sensitized Solar Cells

Transparent conducting oxides (TCO) are commonly used in electrodes of dye-sensitized solar cells (DSSCs). The flexible DSSCs presented in this work was changed to be based on stainless steel (StSt) meshes and the mesoporous TiO2 films were fabricated by electrophoretic deposition (EPD) method which consists of repetitive short-term depositions with intermediate drying. The optimum efficiency was found by changing the TiO2 concentration of EPD solution and the potential difference between the electrodes. The experimental results show that the photovoltaic efficiency (η) of the DSSC with an active size of 1 cm2 is 3.25% under an electric field of 60 V/cm and a TiO2 concentration of EPD solution of 1.0wt%.

Electrochromic Property of Sputtered Amorphous NiO Films

Nickel oxide (NiO) thin films were deposited on ITO/glass substrates by radio frequency magnetron sputtering. The electrochromic property of NiO films was investigated using cyclic voltammograms (CV), performed on NiO films immersed in an electrolyte of 1 M LiClO4 in propylene carbonate (PC). Optical, electrochemical and structural properties of the films, as a function of coloration–bleaching cycle, were characterized using an UV-Vis-NIR spectrophotometer, cyclic voltammetry (CV), X-ray diffraction(XRD) and a field emission scanning electron microscope (FE-SEM). The optimal electrochromic NiO film, with a thickness of 180 nm, exhibits a maximum transmittance variation (ΔT%) of 53.97 %, an optical density change (ΔOD) of 0.66, an intercalation charge (Q) of 14.65 mC/cm2, and a coloration efficiency (η) of 44.85 cm2/C between the colored and bleached states at a wavelength (λ) of 550 nm.

Structural and photoluminescence characteristics of ZnO films by room temperature sputtering and rapid thermal annealing process

The paper reports on the structural and photoluminescence characteristics of ZnO films, which are successfully deposited on SiO/sub 2/-Si substrates at room temperature and annealed at ambient atmosphere from 200/spl deg/C to 900/spl deg/C. X-ray diffraction and scanning electron microscopy are used to study structural changes.