Construction of efficient counter electrodes for dye-sensitized solar cells: Fe2O3 nanoparticles anchored onto graphene frameworks

Exploiting cost-effectiveness and highly efficient counter electrodes (CEs) has been a persistent objective for large-scale practical application of dye-sensitized solar cells (DSSCs). Here, we propose an alternative design for the fabrication of low-cost and Pt-free CE materials by constructing fast electron transport network and creating highly active sites on the electron pathway using graphene and Fe2O3 nanoparticles. The hybridized structure of three-dimensional (3D) graphene frameworks (GFs) supported Fe2O3 nanoparticles is prepared by a simple hydrothermal self-assembly process. Due to the superior electrocatalytic activity originated from the uniformly dispersed Fe2O3 nanopartides and enriched edges and defects on graphene frameworks, along with the incorporation of 3D GFs which provide effective transport pathways for electrons transfer, the DSSC with Fe2O3/GFs as CE display a power conversion efficiency of 7.45%, which is superior to that of Pt as CE (7.29%). Therefore, the Fe2O3/GFs composites exhibit great potential in low-cost and highly efficient CE materials for DSSCs. (C) 2015 Elsevier Ltd. All rights reserved.