In suit growth of CuSe nanoparticles on MXene (Ti3C2) nanosheets as an efficient counter electrode for quantum dot-sensitized solar cells

This paper reports a one-step hydrothermal method of in-situ growing copper selenide (CuSe) nanoparticles on the 2D materials-MXene (Ti3C2) nanosheets to form CuSe/Ti3C2 composite with three-dimensional structure. The CuSe/Ti3C2 slurry prepared via a solvothermal method was screen-printied onto graphite sheet to form a counter electrode (CE) in quantum dot-sensitized solar cells (QDSCs). The CuSe/Ti3C2 CE shows the better electrical conductivity for electron transfer, and a larger specific surface area to provide more active sites for polysulfide electrolyte reduction, as compared to the pristine CuSe CE and Ti3C2 CE. Hence, the device with CuSe/Ti3C2-30 mg CE achieves an efficiencies of 5.12%, which much better than that of CuSe CE (3.47%) and Ti3C2 CE (2.04%). The symmetrical dummy cells consisting of two CEs are further designed to confirm the best electrocatalytic activity and the excellent stability of composite CE towards polysulfide electrolyte. Therefore, CuSe/Ti3C2 is very promising as CE for QDSCs and this strategy provides a facile route for the design of the composite with MXene as a CE for QDSCs.