用光电流作用谱、光电流-电势图等光电化学方法研究了铟锡导电玻璃(ITO)/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)膜电极以及ITO/TiO2/3-己基噻吩和2-噻吩甲酸共聚物(CTCHT)复合膜电极的光电转换性质.结果表明,CTCHT膜为p-型半导体,禁带宽度为2.44eV,价带位置为-5.73eV.研究表明在ITO/TiO2/CTCHT复合膜电极中存在p-n异质结,p-n异质结的存在能够使光生电子和宅穴有效的分离。有效地降低了电荷的反向复合几率,提高了光电转换效率,CTCHT膜修饰ITO/TiO2电极可使光电流增强,使宽禁带半导体电极的光电转换效率得到改善。
The conversion properties of nanostructured TiO2/copolymer of thiophene-2-carboxylic acid and 3-hexylthiophene (CTCHT) film electrode were studied by the photocurrent action spectra and the photocurrent dependence of potential with the CTCHT film bandgap of 2.44 eV. The diagram of energy level of CTCHT film was determined with cyclic voltamogram and photoelectrochemical method. The valence band of CTCHT film was at -5.73 eV, the conduction band was at -3.29 eV and the p-n heteroconjuction is existed in the nanostructured TiO2/CTCHT film electrode, which favors the separation of electron/hole pairs generated by photoexcitation. The nanostructured TiO2/CTCHT film electrode could enlarge the visible optical absorption region and obviously increase the photocurrent in visible region. The photocurrent threshold was shifted to 〉650 nm, thus the conversion efficiency of light to electricity was improved.