Novel Preparation of Anatase TiO2@Reduced Graphene Oxide Hybrids for High-Performance Dye-Sensitized Solar Cells

An effective method was developed to prepare hybrid materials of TiO2 nanoparticles on reduced graphene oxide (RGO) sheets for application in solar cells. The morphology, size, and crystal phase of the TiO2 nanoparticles and TiO2@reduced graphene oxide (TiO2@RGO) hybrids were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), Raman, and UV-vis diffuse reflectance spectroscopy. A possible growth mechanism of TiO2@RGO hybrids is proposed based on observations of the TiO2 nanoparticles obtained from the hydrolysis process under different conditions. The effects of different reduced graphene oxide contents on the energy conversion efficiency of the dye-sensitized solar cells (DSSCs) based on J-V and incident photon-to-current conversion efficiency (IPCE) spectra are also discussed. DSSCs based on TiO2@RGO hybrid photoanodes with a graphene content of 1.6 wt % showed an overall light-to-electricity conversion efficiency of 7.68%, which is much higher than that of pure anatase nanoparticles (4.78%) accompanied by a short-circuit current density of 18.39 mA cm(2), an open-circuit voltage of 0.682 V, and a fill factor of 61.2%.