Hierarchical Fe 3 O 4 -reduced graphene oxide nanocomposite grown on NaCl crystals for triiodide reduction in dye-sensitized solar cells

Cost-effective reduced graphene oxide sheets decorated with magnetite (Fe O ) nanoparticles (Fe O -rGO) are successfully fabricated via a chemical vapor deposition (CVD) technique using iron (III) nitrate as an iron precursor, with glucose and CH as carbon sources, and NaCl as a supporting material. TEM analysis and Raman spectroscopy reveal hierarchical nanostructures of reduced graphene oxide (rGO) decorated with Fe O nanoparticles. Fe K-edge x-ray absorption near edge structure (XANES) spectra confirm that the nanoparticles are Fe O with a slight shift of the pre-edge peak position toward higher energy suggesting that the fabricated Fe O nanoparticles have a higher average oxidation state than that of a standard Fe O compound. The hierarchical Fe O -rGO is found to exhibit an excellent catalytic activity toward the reduction of triiodide to iodide in a dye-sensitized solar cell (DSSC) and can deliver a solar cell efficiency of 6.65%, which is superior to a Pt-based DSSC (6.37%).