Influence of thickness and morphology of MoS2 on the performance of counter electrodes in dye-sensitized solar cells

Abstract

Non-platinum electrodes for photoelectric devices are challenging and attractive to the scientific community. A thin film of molybdenum disulfide (MoS₂) 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 MoS₂ thin films via the cyclic voltammetry (CV) route. Thickness and morphology of the MoS₂ thin films were controlled via the concentration of precursor solution. The obtained results showed that MoS₂ thin films formed at a low precursor concentration had a layered morphology while a honeycomb-like MoS₂ thin film was formed at a high precursor concentration. Both types of MoS₂ thin film were composed of 1T and 2H structures and exhibited excellent electrocatalytic activity for the I₃ ^-/I^- redox couple. DSSCs assembled using these MoS₂ 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 MoS₂ 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.

Keywords: cyclic voltammetry (CV); dye-sensitized solar cells (DSSCs); electrocatalytic activity; honeycomb-like; molybdenum disulfide (MoS2); thin film.