Increasing the surface area of electrodeposited-Pt through adding surfactant for dye-sensitized solar cell application
|Yi-Hsuan Lai 1,2, Chia-Yu Lin 1, Chii-Wann Lin 2,3, Kuo-Chuan Ho 1,4|
1. Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei city 10617, Taiwan
Counter electrodes, as one of important components in dye-sensitized solar cells (DSSCs), play a role of transferring electrons arriving from external circuit back to the iodide (I-)/triiodide (I3-) redox electrolyte and to catalyze the reduction of the redox couple . Although sputtered-platinum (SP-Pt) on conducting glass, such as ITO or FTO, was generally used as the counter electrode in DSSCs for I3- reduction, less attention has been paid to increase the active surface area for I3− reduction as well as the cell efficiency by controlling the morphology of Pt through adding the surfactant in the electrodeposition bath. .
In this study, a Pt counter electrode for ZnO-based DSSCs was prepared by electrochemical deposition of H2PtCl6 on ITO substrate in the presence of nonionic surfactant, t-octylphenoxypolyethoxyethanol (Triton® X-100). Triton® X-100 was selected to achieve an ordered structure for the electrochemically deposited Pt, which is based on the fact that a nonionic surfactant forms liquid crystalline phase that can be used as a template for the production of a well-defined mesoporous Pt . Cyclic voltammetry (CV) was utilized here to compare the I−/I3− redox behavior between the SP-Pt electrode and the electrodeposited-Pt (ED-Pt) electrode. Both the peak current density and the charge capacity for the ED-Pt film are larger than those of the SP-Pt film. This can be interpreted in terms of increased active surface area of this film. The ZnO-based cells fabricated with an ED-Pt counter electrode showed a higher conversion efficiency of 1.69% compared with cell fabricated with a SP-Pt (1.21%) counter electrode under the illumination of 100 mW/cm2. The enhancement was attributed to the increase in the effective surface area of Pt for I3− reduction.
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Presentation: Short communication at SMCBS'2009 International Workshop, by Yi-Hsuan Lai
See On-line Journal of SMCBS'2009 International Workshop
Submitted: 2009-08-31 14:07 Revised: 2009-08-31 14:07