Three-dimensional nitrogen doped holey reduced graphene oxide framework as metal-free counter electrodes for high performance dye-sensitized solar cells

•3D reduced GO framework (NHGF) with unique hierarchical pores is synthesized.•The compressed NHGF paper is used as free-standing counter electrode for DSSC.•The DSSC performance with NHGF paper CE is 5.56% and is higher than using Pt (5.45%).

Three-dimensional nitrogen doped holey reduced graphene oxide framework (NHGF) with hierarchical porosity structure was developed as high-performance metal-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). With plenty of exposed active sites, efficient electron and ion transport pathways as well as a high surface hydrophilicity, NHGF-CE exhibits good electrocatalytic performances for I−/I3− redox couple and a low charge transfer resistance (Rct). The Rct of NHGF-CE is 1.46 Ω cm2, which is much lower than that of Pt-CE (4.02 Ω cm2). The DSSC with NHGF-CE reaches a power conversion efficiency of 5.56% and a fill factor of 65.5%, while those of the DSSC with Pt-CE are only 5.45% and 62.3%, respectively. The achievement of the highly efficient 3D structure presents a potential way to fabricate low-cost and metal-free counter electrodes with excellent performance.

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