Enhanced catalytic performance of MoO3/MoS2-rGO counter electrode towards a Pt-free dye sensitized solar cell

Abstract

The redox process at the electrolyte/counter electrode (CE) interface is a crucial step in achieving efficient charge flow cycles in DSSCs. The work focuses on enhancing the charge kinetics between the electrolyte, and MoO₃ CE using MoS₂-reduced graphene oxide (rGO) composites. Different weight percentages of rGO (5 wt%, 10 wt%, and 15 wt%) are composited with MoS₂. The MoO₃ surface is modified by screen-printing MoS₂, and MoS₂-rGO on it. The dense network of MoS₂, and rGO at the optimized concentration furnishes Pt-like electrocatalytic activity to MoO₃. The 10 wt% of rGO in MoS₂ (M/MSG10) imparts favourable properties to MoO₃ CE by lowering the charge transfer resistance by 2.6-fold and enhancing the electrocatalytic performance. The limiting, and exchange current densities increase by 2.2, and 2.9 times, respectively, compared to MoO₃. M/MSG10 CE exhibits a maximum power conversion efficiency of 5.0 %, which is 2.9 times higher than MoO₃. This champion device outperforms the conventional Pt CE by recording an efficiency 1.1-fold higher. This study identifies Pt-free CE, specifically MoO₃/MoS₂-rGO, as a potential candidate to reduce the cost of DSSCs, and promote commercialization.