A graphene–Bi8La10O27 nanocomposite (GBL) was successfully synthesized by a facile microwave-assisted method, and applied as a counter electrode for efficient dye-sensitized solar cells. This allowed the size and distribution of the Bi8La10O27 nanoparticles formed on a flexible graphene sheet to be effectively controlled, which is crucial for achieving high electrocatalytic activity for I3− reduction. GBL showed the highest catalytic activity and the lowest electrolyte diffusion resistance, mainly due to the homogeneous single-layer immobilization of Bi8La10O27 nanoparticles on a graphene sheet with high density. A dye-sensitized solar cell with GBL as a counter electrode can yield 7.09% photoelectric conversion efficiency, which is comparable to that of the cell with a Pt-film counter electrode (6.23), which demonstrates the application potential of GBL as a low cost non-Pt CE material for DSSCs.
