聚3-甲基噻吩修饰量子点硫化铅连接TiO2纳米结构膜的光电化学研究

采用原位化学法在纳米结构TiO2电极上制备了量子点PbS(Q-PbS), 并用电化学方法在TiO2/Q-PbS表面聚合3-甲基噻吩[poly(3-Methylthiophene), PMeT]. 研究结果表明, PMeT和Q-PbS单独修饰纳米结构TiO2电极和PMeT修饰Q-PbS连接纳米结构TiO2电极的光电流产生的起始波长都向长波方向移动; 在可见光区光电转换效率均比纳米结构TiO2的光电转换效率提高显著; PMeT与Q-PbS修饰的纳米结构TiO2之间存在p-n异质结. 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离, 提高了光电转换效率.

Photoelectrochemical Study of Poly(3-methylthiophere) Modified Q-PbS Anchored Nanostructured TiO2 Film

The PbS quantum dots(Q-PbS) were formed in situ on a nanocrystalline TiO2 electrode by using chemical bath deposition techniques and the PMeT were prepared with electrochemical method on TiO2/Q-PbS film. The photoelectrochemical properties of TiO2/Q-PbS film and poly(3-methylthiophere)(PMeT) modified Q-PbS anchored nanostructured TiO2 film were studied by using the photocurrent action spectra and the photocurrent dependence of potential. The bandgap of Q-PbS films was 1.68 eV. The energy level of Q-PbS film was determined with photoelectrochemical method. The results indicate that PMeT and Q-PbS respectively modified TiO2 film and PMeT modified Q-PbS anchored nanostructured TiO2 film produced photocurrent in the longer wavelength region under a certain condition. In infrared light region, the conversion efficiency of light to electricity for the composite semiconductor nanoporous films was greatly improved comparing with that of the nanostructured TiO2.The experiment result shows that the p-n heterojuction existed in the nanostructure TiO2/Q-PbS/PMeT film electrode, which resulted in the separation of electron/hole pairs generated by photoexcitation, thus photoelectric conversion performance was improved.