Influence of annealing temperature on photoelectronic properties and wettability of TiO2 nanotube arrays

Abstract

TiO2 nanotube arrays (TNs) were prepared by anodization of titanium foil and then annealed at different temperatures (300°C, 400°C, 500°C, 600°C, and 800°C). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV-Vis). Effect of annealing temperature on crystalline structures, morphology, photoelectronic properties, and wettability has been investigated. The results indicate that low temperature (below 500°C) has no obvious influence on surface morphology, while amorphous phase changes into anatase phase and rutile phase. The ultraviolet absorbance decreases while the visible light absorbance slightly increases with the increase of annealing temperature. At 500°C, the TNs show the highest photocurrent and maximum light-induced contact angle change, which are ascribed to their good crystallization, mixed crystal structure, and nanotubular structure.