Boosted Reactivity of Low-Cost Solar Cells over a CuO/Co₃O₄ Interfacial Structure Integrated with Graphene Oxide

Developing cost-effective and environmentally friendly counter electrodes (CEs) with high performance is central for the commercial application of dye-sensitized solar cells (DSSCs). In this work, the porous interfacial CuO/Co₃O₄@GO (CCO@GO) hybrid was fabricated by encapsulating the self-assembled CuO/Co₃O₄ nanosphere in graphene oxide (GO) and acted as a CE for the first time. Further measurements verified that the optimized CCO@GO hybrid not only provided a higher specific surface area (86.7 m² g^–1) with more exposed catalytic sites but also significantly enhanced the power conversion efficiency (PCE = 8.34%) of DSSC, which was higher than those of the Co₃O₄-based CE (2.66%) and commercial Pt CE (7.85%). The results indicate that the interfacial CuO/Co₃O₄@GO hybrid synergistically accelerates the diffusion of a I₃^–/I^– redox couple and transmission of electrons, thus promoting the reaction kinetics. This work provides a remarkable way for exploring economical high-performance Pt-free CEs for DSSCs as well as contributes to their further development for other energy-related fields.