Fe3O4-reducedgrapheneoxide(Fe3O4-RGO)binderfree counter electrode (CE) is prepared by using an easy and lowcost electrophoretic deposition method and controlling the hydrogen evolution process followed by an electrochemical reduction process for dye-sensitized solar cell (DSSC). X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive spectrometer, Raman spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy (TEM) indicate clearly the formation of Fe3O4-RGO nanocomposite. TEM images show that the Fe3O4 nanoparticles with diameters in the range of 10–30 nm are uniformly deposited on RGO. The layerby- layer deposition of iron oxide species anchored on graphene nanosheets during the EPD on FTO provides a unique film for DSSC. To evaluate the chemical catalysis and stability of preparedCEs toward I3− reduction and the interfacial charge transfer properties, Fe3O4-RGO nanocomposite and RGOare characterized by cyclic voltammetry, Tafel polarization, and electrochemical impedance spectroscopy. Under AM 1.5 irradiation (100 mW cm−2), the DSSC based on the Fe3O4-RGO shows a power conversion efficiencyof5.91%,which iscomparable with the Pt CE, suggesting that the Fe3O4-RGO nanocomposite is an effective CE material for low-cost DSSC. The proposed approach can prepare a thin film of Fe3O4-RGO at short time with suitable performance in DSSC.
