Facile and cost-effective methodology to fabricate MoS2 counter electrode for efficient dye-sensitized solar cells

Interests in the development of economical and high-efficiency counter electrodes (CEs) of dye-sensitized solar cell (DSSC) to replace the excessively cost and scarce platinum (Pt) CEs have been increased. In this report, we demonstrate a facile chemical bath deposition (CBD) route to prepare layered MoS2/fluorine-doped tin oxide (FTO) films that directly act as the CEs of DSSCs. A DSSC containing the CBD-synthesized MoS2/FTO CE (prepared at 0.03 M Mo source concentration, 90 degrees C bath temperature and 30 min deposition time) exhibits high power conversion efficiency (PCE) of 7.14%, which is approaching that of DSSC with Pt/FTO CE (8.73%). The electrocatalytic activity of the MoS2/FTO and Pt/FTO CEs are discussed in detail with their cyclic voltammetry (CV), Tafel polarization curves, and electrochemical impedance spectra (EIS). The observed results indicate that our low-cost CE has a high electrocatalytic activity for the reduction of triiodide to iodide and a low charge transfer resistance at the electrolyte-electrode interface with a comparable state to that of a Pt/FTO CE.