A facile way to fabricate graphene sheets on TiO2 nanotube arrays for dye-sensitized solar cell applications

Large-area graphene sheets on TiO2 nanotube arrays (RGO/TNAs) were fabricated using a simple electrochemical method. The RGO content loaded on the arrays was controlled by changing the electrochemical reaction time. The microstructures and properties of RGO/TNAs were characterized and measured using field emission scanning electron microscopy, X-ray diffraction pattern, X-ray photoelectron spectroscopy, FT-IR spectra, and ultraviolet-visible (UV-Vis) spectroscopy. The results indicated that an appropriate reaction time clearly enhances photoelectrochemical properties, while excessive RGO loading significantly lowers their performance. Remarkably, in sharp contrast to the dye-sensitized solar cells prepared by TNAs as photoanode, the RGO/TNAs showed a significantly enhanced power conversion efficiency of 4.46 %. The improvement of light harvesting is due to the excellent property of RGO and the special structure of the composite.