LAUSR

Abstract The development and design of counter electrode (CE) materials using an excellent catalytic activity and cyclic stability have a significant importance for further achieving better photoelectric conversion efficiency (PCE) of dye-sensitised solar cells (DSSCs). Achieving an efficient integration of ternary active components into the CEs and understanding the interaction between the ternary components are desired. Herein, a multistep transformation approach to constructing NiS nanosheets that are fixed on the surface of N-doped hollow thin shell carbon spheres (NHCS), and then encapsulated using reduced graphene oxide (RGO) to form an NHCS/NiS/RGO nanocomposite, is demonstrated. The nanocomposite shows an excellent electrochemical property and further probes the interfacial charge distribution behaviour as a CE for DSSCs. The interfacial charge polarisation with a large surface area of RGO facilitates a charge transfer, and evenly distributed NiS nanosheets on the surfaces of the NHCS gathering electrons lead to a strong interfacial coupling and simultaneously further boost the charge transfer, as well as triiodide oxidation and reduction, with remarkable ternary functional electrode activities. A device with an NHCS/NiS/RGO nanocomposite as a CE produces a better photovoltaic conversion efficiency (PCE) of up to 9.32% more than the Pt as a CE (8.06%). This study not only offers a strategy to achieving a ternary-functional-catalyst material with a superb performance, but also unravels the role of the geometric configuration factor of the hybrid from the view of the interfacial charge distribution, offering an abundant prospective roadmap of electrode materials in energy devices.