Influence of thickness and morphology of MoS ₂ on the performance of counter electrodes in dye-sensitized solar cells

Non-platinum electrodes for photoelectric devices are challenging and attractive to the scientific community. A thin film of molybdenum disulfide (MoS ₂ ) was prepared on substrates coated with fluorine-doped tin oxide (FTO) to substitute the platinum counter electrode (CE) for dye-sensitized solar cells (DSSCs). Herein, we synthesized layered and honeycomb-like MoS ₂ thin films via the cyclic voltammetry (CV) route. Thickness and morphology of the MoS ₂ thin films were controlled via the concentration of precursor solution. The obtained results showed that MoS ₂ thin films formed at a low precursor concentration had a layered morphology while a honeycomb-like MoS ₂ thin film was formed at a high precursor concentration. Both types of MoS ₂ thin film were composed of 1T and 2H structures and exhibited excellent electrocatalytic activity for the I ₃ ^–/ I ⁻ redox couple. DSSCs assembled using these MoS ₂ CEs showed a maximal power conversion efficiency of 7.33%. The short-circuit value reached 16.3 mA·cm ⁻² , which was higher than that of a conventional Pt/FTO CE (15.3 mA·cm ⁻² ). This work reports for the first time the possibility to obtain a honeycomb-like MoS ₂ thin film morphology by the CV method and investigates the effect of film structure on the electrocatalytic activity and photovoltaic performance of CEs for DSSC application.