A dye-sensitized solar cell based on magnetic CoP@FeP4@Carbon composite counter electrode generated an efficiency of 9.88%

Transition metal phosphates have aroused wide attention and been applied in the field of energy conversion due to their high catalytic properties and low cost, but magnetic metal phosphates are rarely used in DSSC. In this work, the magnetic CoP@FeP4 thin film was prepared on carbon paper (CP) using a two-step process and proposed as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). The morphology of CoP@FeP4@CP with a silkworm-like structure is advantageous to enhance the catalytic ability for the interface reaction, establish a good connection between the electrode material and electrolyte, and accelerate the electron transmission. The characterizations using cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel curves all indicate that the CoP@FeP4@CP CE shows excellent electrochemical catalytic performance for the I−/I3− electrolyte. Under optimal conditions, a high power conversion efficiency of 9.88% is achieved for DSSC with CoP@FeP4@CP CE much higher than that of Pt (7.49%) and CoP@CP (8.73%) CEs. This phenomenon can be attributed to the unique chemical structure and the synergistic effect of CoP@FeP4@CP CE. CoP@FeP4@CP CE with the advantages of efficient, low cost, and facile synthesis is a promising alternative to the expensive Pt CE for the DSSCs in the future.