阳极氧化膜WO_3(Ⅱ)——电显色的介质效应

WO_3 Anodic Oxide Film (Ⅱ)--Effect of Media on- Electrochromic Process

用循环计时电量法、循环伏安法、电化学现场(in-situ)紫外可见反射光谱技术和光电流谱技术研究了溶剂和阳离子(H^+,Li^+)对阳极氧化膜WO_3电显色稳定性和过程的影响。从循环计时电量图可以测定表征膜稳定性的氢或锂的累积量和暂态周期数。实验发现W/WO_3/LiCLO_4乙腈溶液体系具有高的电显色稳定性。引起WO_3膜可逆电显色的H^+和Li^+离子的嵌-脱过程的界面电化学机理不同。着色态WO_3膜的色心是自由电子,其密度超过10^(21)/cm^3,生色机理是等离子体振荡。

The effect of solvents and cations of H+ and Li+ on the- electrochromic stability and process at the WO3 anodic, oxide film were investigated by using cyclic chronocoulometry , cyclic voltamme-try, in situ UV/Vis reflectance spectroscopy and photocurrent spectroscopy. The parameters of hydrogen or lithium accumulation amount in the film and the number of the transient perods which can be determined from the Q^t transient can be characteristic of the stability of the film, It can be found that the electrochromic system of W/WO3/LiClO4 solution in acetonilrile has a high stability. The in-terfacial electrochemical mechanism of the injection-extraction of Li ions in the electrochromic process is quite different from H+ ions. The color center for the anodic oxide film WO3 is considered to be the free electrons whose density is over 1021/cm3 and the optical transition, i. e, coloring process, arises from the plasma oscillation.