Abstract
We utilize nanoscale carbon materials as the counter electrodes of dye-sensitized solar cells (DSSCs) to explore how the catalytic ability of carbon electrodes responds to iodium/triiodide redox. We find that the surface area of carbon electrodes has markedly influences on the charge transfer resistance, the efficiency of catalytic process of I3－ ions, and the energy conversion efficiency. Through the relationship between charge transfer and mass transfer control, nanocarbon electrodes possess the ability to catalyze electrolyte; on the other hand, both MWNTs and LWNTs only play the role of assistance. Moreover, according to the experimental result, the catalytic ability of nanocarbon electrodes is inferior to the Pt electrode. The energy conversion efficiency of thermal deposited Pt and LWNTs counter electrodes are 4.136 % and 3.156 %, respectively, which indicates that LWNTs has the potential to substitute Pt as counter electrodes of DSSCs. This energy conversion efficiency of the Pt/LWNTs electrode can be enhanced due to increasing surface areas of LWNTs and employing Pt particles as the active sites of catalysis. This work proposes a thorough method to analyze counter electrode and shows how the parameters such as structure, morphology, surface areas, and defects of materials, affect the electric conductivity, catalytic activity, and stability of the electrode. Furthermore, this study also establishes a criterion for the application of carbon materials as counter electrode in DSSCs.