Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (8): 1487-1494.doi: 10.3866/PKU.WHXB201405272

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Influence of pH Values on the Structure and Performance of a Polypyrrole Counter Electrode for Dye-Sensitized Solar Cells

SU Jia1,2, LU Shan2, WANG Sha-Sha2, ZHANG Xue-Hua2, FU Yu-Bin1, HE Tao2   

  1. 1. Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100, Shandong Province, P. R. China;
    2. National Center for Nanoscience and Technology, Beijing 100190, P. R. China
  • Received:2014-04-17 Revised:2014-05-26 Published:2014-07-18
  • Contact: ZHANG Xue-Hua, FU Yu-Bin, HE Tao E-mail:zhangxh@nanoctr.cn;ffyybb@ouc.edu.cn;het@nanoctr.cn
  • Supported by:

    The project was supported by the Ministry of Science and Technology of China (2010DFB63530), National Natural Science Foundation of China (51043010, 21203039), and Hundred-Talent Program of Chinese Academy of Sciences.

Abstract:

The pH of the solution used to produce an electro- polymerized polypyrrole (PPy) film has a significant impact on the morphology and properties of the resulting film and, by extension, on the electrocatalytic activity of the film for the I-/I3- redox reaction. Accordingly, the performance of dye-sensitized solar cells (DSSCs) based on PPy counter electrodes (CEs) is affected by solution pH. In this study, p-toluene sulfonate ion-doped PPy (PPy-TsO) CEs on fluorine-doped tin oxide (FTO) glass substrates were fabricated using an electrochemical method under a constant bias in solutions with various pH values. The effect of the pH of the synthetic solution on the morphology, structure, and electrocatalytic activity during the I-/I3- redox reaction of the obtained PPy CEs was thoroughly investigated by scanning electron microscopy (SEM), UV-Vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). A pH value of 2.0 was found to represent the optimal value, since the PPy-TsO film produced at this pH exhibited the highest degree of doping, the longest conjugation length, and the highest catalytic activity. When working as the CE of a DSSC, this film also showed the highest power conversion efficiency. Films synthesized at pH values either above or below 2.0 exhibited inferior properties and lower performance when in DSSCs.

Key words: Polypyrrole, Electrochemical polymerization, pH value, Electrocatalytic activity, Counter electrode, Dye-sensitized solar cell

MSC2000: 

  • O646