Enhanced electrocatalytic activity in dye-sensitized solar cells via interface coupling of the CoFe2O4/Co3Fe7 heterostructure

The exploitation of high-efficient yet non-precious counter electrode (CE) materials is of great significance for practical applications of dye-sensitized solar cells (DSSCs). Herein, Co 3 Fe 7 alloy anchored on the porous core-shell CoFe 2 O 4 composites (CoFe 2 O 4 /Co 3 Fe 7 ) were successfully manufactured as a counter electrode for DSSC. The detailed electrochemical measurements verified that the introduction of Co 3 Fe 7 alloys modifies the original core-shell structure, contributing to enhance electrical conductivity and promote interfacial electron transfer. While the porous structure increases the potential for exposing active sites and accelerates the diffusion of iodide ions. Moreover, the formation of hetero-junction facilitates the generation of active facet sharing and multi-component synergy, thus prominently boosting the reduction of triiodide and accelerating reaction kinetics. As a consequence, DSSCs structured with CoFe 2 O 4 /Co 3 Fe 7 -modified CEs achieve a satisfactory power conversion efficiency (PCE) of 8.54%, which surpasses that of conventional platinum (7.70%). Meanwhile, the stability of CoFe 2 O 4 /Co 3 Fe 7 CE is also enhanced than noble metals platinum. This work highlights that the heterogeneous CoFe 2 O 4 /Co 3 Fe 7 with a rich interface can effectively stimulate the catalytic activity of reducing triiodide to enhance the performance of the solar cell. This strategy also paves the way for enhancing material activity in the field of energy storage and conversion.