Reasonable construction of Fe3O4/Ni@N-RGO nanoflowers as highly efficient counter electrodes for dye-sensitized solar cells

The rational design of high-performance yet low-cost counter electrodes (CEs) with exceptional catalytic activity for the I−/I3− redox couple and excellent corrosion resistance is of great importance for dye-sensitized solar cells (DSSCs). Metal nickel-based CEs have super electrical conductivity for the oxidation of I−, but they lack the ability to restore I3−, leading to relatively poor photoelectric conversion efficiency (PCE). Herein, we propose the design and development of a novel nanostructured CE material composed of hierarchical porous Fe3O4 nanoflowers decorated with Ni nanoparticles and wrapped by N-doped reduced graphene oxide nanosheets (Fe3O4/Ni@N-RGO). The as-prepared multi-component electrode material was applied as a CE for DSSCs, attaining high efficiency and excellent stability. The PCE of Fe3O4/Ni@N-RGO based DSSCs reaches 8.96%, which is superior to those based on Fe3O4 (7.92%) or Pt (7.87%). Moreover, the Fe3O4/Ni@N-RGO electrode also displays ultrahigh corrosion resistance under complicated working conditions. The advantages of the Fe3O4/Ni@N-RGO electrode material indicate its good potential for application in DSSCs as a high-performance and inexpensive CE material.