Triiodide reduction activity of hydrangea molybdenum sulfide/reduced graphene oxide composite for dye-sensitized solar cells

The molybdenum sulfide/reduced graphene oxide (MoS₂/rGO) composite is prepared by a hydrothermal method. The hydrangea MoS₂ powder is composited with rGO to serve as a low-cost and non-platinum counter electrode (CE) to improve photovoltaic performance for dye-sensitized solar cells (DSSCs). The Tafel polarization and electrochemical impedance spectroscopy (EIS) indicate that the MoS₂/rGO counter electrode has exceptional electrocatalytic ability and reduction reaction kinetics for the I⁻/I₃⁻ couples on the counter electrode, which is due to hydrangea structure MoS₂ formed on rGO surface and matrix as well as the MoS₂/rGO composite strongly attached on FTO substrate. The DSSC with novel MoS₂/rGO CE achieves a higher power conversion efficiency of 6.72% than that with Pt CE (5.74%) under standard sunlight illumination.