Papers by Author: Chih Ming Wang

Abstract: This work present a low resistance dye-sensitized solar cell (DSSC) based on metal substrates. Different kinds of metal meshes are used to fabricate nanocrystalline TiO2 electrode and counter-electrode. The nanoporous TiO2 thin films were fabricated via an aerosol deposition method. The TiO2 colloid was produced by dissolving P25 powder in deionized (DI) water and atomized using an ultrasonic nebulizer. The flexible electrodes can be sintered under 450–550 °C and exhibit high-temperature sinterability. The tuning of TiO2 film thickness coated on metal mesh towards optimization of solar energy conversion efficiency had been investigated. Experimental results show that the excellent electric conductivities improve the fill factor and conversion efficiency for the large-size DSSCs due to the reduced internal resistance of the cell. These flexible metal substrates are a promising approach especially from the viewpoint of large-scale, cost effective industrial manufacturing of solar cells.

Abstract: 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.

Abstract: In this present work, we adopt conventional solid state reaction techniques to obtain CaCu3Ti4O12 (CCTO) ceramics and the dielectric properties of polycrystalline CCTO samples sintered in the temperature range 900 − 1100°C were investigated. X-ray diffraction (XRD) patterns show no obvious change in crystal phase with various sintering temperature. However, experimental results show that the dielectric properties of CCTO ceramics are very sensitive to processing parameters and the dependence of dielectric constant and loss tangent of CCTO ceramic on processing can be obtained. The effect of sintering conditions on the surface microstructures and the electrical properties of CCTO ceramics are also discussed in this study.