Tungsten Phosphide Microsheets In-Situ Grown on Carbon Fiber as Counter Electrode Catalyst for Efficient Dye-Sensitized Solar Cells

The development of low-cost, green, and pollution-free counter electrode materials with high catalytic activity plays a critical role in improving the photovoltaic performance of dye-sensitized solar cells (DSSCs). In recent years, transition metal phosphides have been widely used in DSSCs due to their outstanding catalytic activity and stability. Herein, a novel binary phosphide is immobilized on carbon paper (CP) by a two-step strategy. This strategy involves the preparation of WO3 precursor by the hydrothermal method, and synthesis of tungsten phosphide (WP) with the vapor deposition method, which finally leads to the uniform dispersion of WP on carbon paper. The acquired WP/CP counter electrode demonstrates high electrical conductivity and prefect catalytic ability for reducing triiodide, and the DSSCs assembled with WP/CP counter electrode achieve a high-power conversion efficiency of 10.29%, which is superior to that of the Pt-based (7.34%). These findings illustrate that the WP microsheets in-situ grown on carbon paper are a potential candidate to replace Pt as an economical and efficient counter electrode for DSSCs.