Preparation And Photoelectric Performance Of Graphene/TiO₂ Composite Films

Graphene is an important discovery after carbon nanotube and fullerene. Graphene has wide potential applications in the fields of nanoelectronic devices, battery materials, field emission materials, hydrogen storage materials and ultra-sensitive sensors, because of its excellent mechanical property, electrical property and thermal property. The composite consisted of graphene and TiO2 has attracted much attention, since the composite can improve the photoelectric performance of solar cell.In this paper, based on the TiO2 sol, the various graphene composite films were prepared by dipping-lifting. The films as-abtained were characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Ultraviolet-visible Spectrophotometer (UV-vis), Energy dispersive X-ray (EDX). The mechanism of charge transfer and the effect factors for the films were discussed, and the photoelectric conversion of the films was evaluated.Main work as follows:1. The preparation and photoelectrichemistry performance of Graphene/TiO2 composite filmThe graphene/TiO2 composite film on the conducting glass plate was prepared by dipping-lifting in sol-gel solution containing graphene oxide and reducing process. The films as-obtained were characterized by XRD, SEM, EDX and UV-vis. The photoelectric conversion property of films was examined at the electeochemical workstation with UV lamp as light source. The relationship of the photoelectric conversion efficiency with the layers of the composite films and the mechanism of charge transfer in the films were discussed. The results indicate that the graphene/TiO2 has a good photovoltaic property. The largest photocurrent was obtained by the graphene/TiO2 composite film with single layer.2. The preparation and photoelectrichemistry performance of Ag/Graphene/TiO2 composite film By dipping-lifting in sol-gel solution containing graphene oxide and reducing process, the graphene/TiO2 composite film on the conducting glass plate was first prepared. Then, the Ag/graphene/TiO2 composite film was fabricated by interface reaction with AgNO3 and N2H4·H2O on the surface of graphene/TiO2 composite film. The films as-obtained were characterized by XRD, SEM, EDX and UV-vis. The photoelectric conversion property of films was examined at the electeochemical workstation with UV and xenon lamp as light sources. The relationship of the photoelectric conversion efficiency with the graphene oxide amount added in titanium hydroxide sol and the mechanism of charge transfer in the films were discussed. The results indicate that the photovoltaic property of Ag/graphene/TiO2 composite film as-obtained is excellent. The largest photocurrent was obtained by the Ag/graphene/TiO2 composite film prepared with 1.0 ml 1.0 mg/ml graphene oxide mixed in titanium hydroxide sol.3. The preparation and photoelectrichemistry performance of CdS/Graphene/TiO2 composite filmBy dipping-lifting in sol-gel solution and reducing process, the graphene/TiO2 composite film on the conducting glass plate was first prepared. Then, the CdS/graphene/TiO2 composite film was fabricated by interface reaction with Cd(NO3)2 and Na2S on the surface of graphene/TiO2 composite film. The films as-obtained were characterized by XRD, SEM, EDX and UV-vis. The photoelectric conversion property of films was examined at the electeochemical workstation with xenon lamp as light source. The relationship of the photoelectric conversion efficiency with the the CdS amount in the composite film and the mechanism of charge transfer were discussed. The results indicate that the photovoltaic property of CdS/graphene/TiO2 composite film as-obtained is excellent. The largest photocurrent was obtained by the CdS/graphene/TiO2 composite film prepared with 0.1 mol/L solution and 0.1 mol/L Cd(NO3)2 solution.