LAUSR

Owing to it being low-cost and eco-friendly and having multiple oxidation states, the ternary transition metal oxide CuCo2O4 has been used as an electrode material with superior electrocatalytic activity in numerous fields. However, its application in quantum dot-sensitized solar cells (QDSSCs) has not been investigated. Herein, we synthesized porous hollow micro-spherical CuCo2O4 nanomaterials by simple solvothermal and calcination processes and then applied them in QDSSCs as counter electrodes (CEs). Because of the low density, good shell permeability of the hollow porous structure and high catalytic activity of the material, QDSSCs achieved a higher efficiency of 6.19%. Furthermore, considering the structural flexibility, large specific surface area and high conductivity of graphene, CuCo2O4/RGO composites were further prepared. QDSSCs equipped with optimized CuCo2O4/RGO12 CEs achieved a power conversion efficiency (PCE) of up to 7.04% with Jsc = 22.83 mA cm-2, Voc = 0.61 V, and FF = 0.51, which is higher than that of the pure CuCo2O4 CE. Both EIS and the Tafel test proved that the CuCo2O4/RGO12 CE has the best catalytic activity and electron transport performance, which is beneficial for the regeneration of the S2-/Sn2- redox couple. The prominent cell performance mainly depends on the combination of the abundant catalytically active sites of CuCo2O4 and the excellent conductivity and structural flexibility of graphene.