Mn3O4/graphene composite as counter electrode in dye-sensitized solar cells

Mn3O4-anchored reduced graphene oxide (Mn3O4/RGO) nanocomposites have been successfully synthesized via a facile, effective, energy-saving technique. The surface morphology and structure of the Mn3O4/RGO composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), high resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET) surface area and Barrett-Joyner-Halenda porosity (BJH). The composite material was applied as the counter electrode (CE) for dye-sensitized solar cells (DSSCs). Electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and Tafel polarization measurements revealed a better electrocatalytic performance for the reduction of triiodide in Mn3O4/RGO based DSSCs, compared with the devices with reduced graphene oxide (RGO) CEs. The Mn3O4/RGO improves the fill factor by 56% and the power conversion efficiency of this kind of DSSC reaches 5.90%, which is much higher than the DSSC assembled from RGO CEs. A Pt counter electrode as a reference was also tested.