Single-layer graphene-TiO2 nanotubes array heterojunction as photoanode to enhance the photoelectric of DSSCs

Abstract Photoanode optimization of the dye-sensitized solar cell (DSSC) is a crucial way to improve efficiency. In this investigation, a kind of heterojunction fabricated based on TiO2 nanotubes and graphene by wet transfer method, furthermore, the heterojunction was fabricated as photoanode of DSSC. This method has the advantages of simple operation and time-saving, and micromorphological characterization revealed that graphene and TiO2 combined well. UV-Visible diffuse-reflectance spectrum and photon-to-current conversion efficiency (IPCE) data demonstrated that the graphene transfer enhanced the cell's absorbance in the visible range and reduced the bandgap. The J-V curve was obtained under solar simulation, and the conversion efficiency of 4.18% was reached, which is 83% higher than that of graphene free cell. Therefore, the heterojunction of graphene/TiO2 nanotubes makes a promising prospect for further applications in DSSCs.