Enhanced Performance Of Low-Cost Dye-Sensitized Solar Cells With Pulse-Electropolymerized Polyaniline Counter Electrodes

In this study, the pulse potentiostatic electropolymerization of anilines was employed in synthesizing polyaniline (PANI) nanofibers with rough surface morphology onto a fluorinated tin oxide (FTO) glass substrate as a Pt-free counter electrode (CE) for low-cost dye-sensitized solar cells (DSCs) for the first time. A variety of pulse parameters were investigated to control the surface morphology of PANI nanofibers. After the optimization, the well-distributed rough PANI nanofibers with the diameter of 100 nm can be obtained under 1.1V pulse-on potential, DV pulse-reversal potential, 1 s pulse-on period, 0.5s pulse-reversal period, and total 150s duration time. The extensive cyclic voltammograms revealed that the pulsed PANI CE not only had superior electrocatalytic activity for I-3(-) reduction, but also exhibited excellent electrochemical stability. Moreover, the electrochemical impedance spectroscopy showed the pulsed PANI CE had the relatively lower series resistance and charge-transfer resistance than those of the PANI CE prepared by the conventional potentiostatic (I-t) electropolymerization. Therefore, the DSC assembled with the pulsed PANI CE exhibited an enhanced photovoltaic conversion efficiency of 5.19% (compared to 4.35% for the DSC with the I-t PANI CE) up to similar to 90% level of the DSC using the Pt CE. As the result, the pulsed PANI CE can be considered as a promising alternative CE for low-cost DSCs. (C) 2012 Elsevier Ltd. All rights reserved.