Hydrothermal preparation and optical properties of orientation-controlled WO3nanorod arrays on ITO substrates

Abstract

The orientation controlled synthesis of h-WO₃ nanostructures on ITO substrates has been successfully realized in large scale via a simple hydrothermal method. The influences of pH value and growth time on the orientation and morphology of WO₃ nanostructures were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The nanorod bundles parallel to ITO substrate and nanorod arrays vertical to ITO substrate can be selectively prepared by adjusting the final pH value just to 2.0 and 2.4, respectively. The morphology evolution and the growth mechanism of well aligned WO₃ nanorod arrays were intensively studied. Moreover, the optical properties of the WO₃ with different oriented alignment were also examined.