Synergistic NiO/Fe2O3 heterostructure-enhanced electrocatalytic performance in dye-sensitized solar cells

Abstract

Dye-sensitized solar cells (DSSCs) can efficiently convert solar energy into electricity, which is considered a promising approach to reduce the dependence on fossil resources. However, the development of counter electrodes (CEs) has been limited. Hence, the search for efficient earth-abundant CE materials is highly desired. Herein, an improved simple synthesis method is reported for the deep optimization of electrode activity by coupling the N-defect carbon with the NiO/Fe₂O₃ heterojunction (denoted as NiO/Fe₂O₃@NC). The carbon layers with large specific surface area and high conductivity as bridging transporters not only can maintain structural stability but full exposure to active sites. Moreover, the synergetic effect of NiO and Fe₂O₃ can promote I₃⁻ reduction reaction and suppress iodide ion coupling simultaneously. The obtained NiO/Fe₂O₃@NC serves as CEs. Compared with the unsupported NiO@NC, the Fe₂O₃@NC composites displayed superior electrochemical properties. Meanwhile, the power conversion efficiency (PCE) of DSSC with NiO/Fe₂O₃@NC CE attained 8.69%, exceeding that with NiO@NC (6.51%), Fe₂O₃@NC (6.22%), and commercial Pt CEs (7.52%). This study would contribute to the construction and development of excellent electrocatalysts for other important reactions.