환원 백색소자인 텅스텐 산화물 적극 계면의 전기화학적 특성 연구 = The Electrochemical Characteristics on the Surface of Tungsten Oxide Electrode as Cathodic Coloring Material

다국어 초록 (Multilingual Abstract)

The phenomenon of the electrochromism of tungsten oxide films, which were deposited by electron-beam vacuum evaporation on indium tin oxide(ITO) glass and by thermal oxidation of tungsten bulk, was studied in H₂SO₄ solution. The electrochemical characteristics of these two kinds of electrodes were examined by cyclic voltammetry and Tafel polarization method. Considering the effect of dissolved oxygen on the Tafel polarization, the ion exchange current densities were slightly increased, while the catholic Tafel slopes were decreased with an increase of oxygen content. If the coloring process is assumed completely irreversible, the number of electrons or protons consumed in the coloring reaction would be 0.62 as a maximum value. This indicates that the evaporated film used in this study provided the good reactivities for the electrochromic reaction. The Tafel slope was linearly decreased with the decrease of hydrogen ion concentration and the reaction mechanism seems to be changed in a solution with very low hydrogen ion concentration. From the results of SEM, severe and moderate cracks were observed on the surface of thermally oxidized films and evaporated films, respectively. By the analysis of XRD, the structure of thermally oxidized film was identified as polycrystalline, whereas that of evaporated film was amorphous.