Study of the morphological, optical, structural and photoelectrochemical properties of TiO2 nanorods grown with various precursor concentrations

Abstract

Vertically aligned TiO2 nanorods were grown on a fluorine-doped tin oxide (FTO) substrate covered with a TiO2 buffer layer by using the hydrothermal method with various titanium precursor concentrations. In this study, the effects of the precursor concentration on the morphological, structural, optical and photoelectrochemical properties of TiO2 nanorods were investigated. We observed that photoelectrochemical properties were mainly dependent on the nanorod length, surface area, transmittance and (002) XRD peak intensity, which indicates the oriented growth of the TiO2 nanorods perpendicular to the substrate. As a result, the sample grown from a 0.09 M precursor solution, which grew vertically and had the highest surface area, showed the highest photocurrent density, 0.733 mA/cm2 (at 1.0 V vs. SCE). Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to characterize the morphology of the nanorods, X-ray diffraction (XRD) was used to detect the structural properties of the nanorods, UV-visual spectroscopy was used to measure the optical properties, and analysis with a three-electrode potentiostat was used to measure the photoelectrochemical properties.