单晶硫化镉光电化学电池中光阳极特性的研究

测量了单晶CdS电极在多硫体系和铁氰体系溶液中的光极化特性和波长响应特性,并由此计算出转换效率、填充因子和禁带宽度等有关参数。测量了CdS电极在不同频率下的阻抗谱,复数平面图近似半圆,表明电极/电解液的界面结构可以用一个较简单的模型来描述。Mott-Schottky关系线性良好,外延到电位轴得到的平带电位与光极化曲线上电流换向点电位相符。还发现平带电位与溶液pH值之间存在线性关系,可以用电极表面的水化氧化物膜与溶液中的H_aq⁺离子存在某种平衡来解释。

STUDIES ON ANODIC CHARACTERISTICS OF SINGLE CRYSTAL CdS PHOTOELECTROCHEMICAL CELL

The photopolarization and wavelength response of single crystal CdS electrode in polysulfide and cyanide couple were measured. The conversion efficiency, fill factor and band gap were then calculated. Impedance spectra were also measured using a frequency response analyzer at various frequencies. The complex plane diagrams obtained were approximately equal to a semicircle, therefore,the interfacial structure can be described with asimple model.The Mott-Schottky plots show a good linearity. By extrapolating these straight lines to the potential axis the flat-band potentials were obtained which were quantitatively in agreement with potentials of photocurrent transition in photopolarization curves. A linear relationship was found between the flat-band potential of CdS electrode and the pH value of the redox couple. This relationship is explained in ferms of the formation of hydrated oxide film on the surface of CdS electrode in equilibrium with the H_aq⁺ ions in solution.