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, Co3Fe7 alloy anchored on the porous core-shell CoFe2O4 composites (CoFe2O4/Co3Fe7) were successfully manufactured as a counter electrode for DSSC. The detailed electrochemical measurements verified that the introduction of Co3Fe7 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 CoFe2O4/Co3Fe7-modified CEs achieve a satisfactory power conversion efficiency (PCE) of 8.54%, which surpasses that of conventional platinum (7.70%). Meanwhile, the stability of CoFe2O4/Co3Fe7 CE is also enhanced than noble metals platinum. This work highlights that the heterogeneous CoFe2O4/Co3Fe7 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.

Automated summary

This study successfully prepared CoFe2O4/Co3Fe7 composite materials as the CE for DSSCs, modifying the core-shell structure, enhancing electrical conductivity, promoting electron transfer, accelerating ion diffusion, and achieving a higher power conversion efficiency than traditional platinum.