Electrospun Carbon Nanofibers as Low-Cost Counter Electrode for Dye-Sensitized Solar Cells

摘要

Electrospun carbon nanofibers (ECNs) have been explored as an electrocatalyst and low-cost alternative to platinum (Pt) for triiodide reduction in dye-sensitized solar cells (DSCs). The results of electrochemical impedance spectroscopy (E1S) and cyclic voltammetry measurements indicated that the ECN counter electrodes exhibited low charge-transfer resistance (R_(ct)). large capacitance (C). and fast reaction rates for triiodide reduction. Although the efficiency (η) of ECN-based cells was slightly lower than that of Pt-based cells, their short circuit current density (J_(sc)) and open circuit voltage (V_(oc)) were comparable. The ECN-based cells achieved an energy conversion efficiency (η) of 5.5 % under the AM 1.5 illumination at 100 mW cm~(-2). The reason for lower cell performance using the ECN electrode was because of its lower fill Factor (FF) than that of Pt-based cells, probably caused by high total series resistance (R_(Stot))at ～15.5Ωcm~2. which was larger than that Of ～4.8Ωcm~2 in the Pt-based devices. Simulated results showed that the fill factor (FF) and η could be substantially improved by decreasing R_(Stot), which might be achieved by using thinner and highly porous ECNs to reduce the thickness of the ECNs counter electrode.