Low-temperature, solution-deposited metal chalcogenide films as highly efficient counter electrodes for sensitized solar cells

Abstract

Transition metal chalcogenide crystalline films FeSe₂, Cu_1.8S, and CuSe have been deposited from solution by drop casting their dissolved inks onto a conductive substrate, followed by a mild thermal treatment. We demonstrate that the resulting chalcogenide films exhibit an excellent catalytic activity and function as highly efficient counter electrodes (CEs) for dye- and quantum dot-sensitized solar cells (DSCs and QDSCs). In particular, the FeSe₂ and CuSe films produced herein with novel morphologies show better catalytic activity than that of the conventional Pt coated CE used in DSCs and Cu₂S in QDSCs, respectively. Ensuing devices present an improved photovoltaic performance with maximum values of 9.10% for DSCs and 4.94% for QDSCs, comparable to those based on Pt and Cu₂S CEs. The efficient CE materials developed here from such a facile and scalable route offer strong potential for a broader solar cell application that requires low-cost and large-scale production.