Photoelectric properties of the layered raspberry sandwich amorphous ZnCo2S4@MnCo2S4/CP composite counter electrode in semiconductor-sensitized solar cells

Abstract

Multistage amorphous materials have promising applications in the catalytic performance of dye-sensitized solar cells (DSSCs). Herein, an amorphous sheet–raspberry sandwich-like ZnCo₂S₄@MnCo₂S₄/CP composite material was rationally designed and developed as a counter electrode (CE) for DSSCs by applying a three-step hydrothermal method. The first development of the amorphous composites as CEs resulted in lower charge transfer resistance at the CE/electrolyte interface and improved the fill factor and short-circuit current density. The excellent catalytic performance is mainly attributed to the large number of unsaturated coordination sites generated by the undirected structure of the lamellar–raspberry intercalated amorphous material, the smooth ion transport interface with a self-built corrosion-resistant layer, coupled with the dual catalytic performance of the Zn, Co, and Mn composites, and the good electrical conductivity of the C substrate. When ZnCo₂S₄@MnCo₂S₄/CP was used as the CE on a Ti substrate, the photoelectric conversion efficiency was as high as 11.68% (V_oc = 0.821, J_sc = 20.14 mA cm⁻², and FF = 0.71) under 100 mW cm⁻² light illumination. This paper provides a design idea for amorphous materials in terms of catalytic performance and a method for developing alternatives to Pt electrodes.