Electrospun tailored ZnO nanostructures – role of chloride ions

Abstract

A novel way of transforming ZnO nanospheres to nanorods using an electrospinning technique has been identified as a simple method to control the growth of nanostructures. In this work, ZnO nanospheres and pencil like nanorods were successfully grown using an electrospinning technique with a precursor solution containing polyvinyl alcohol (PVA) and zinc acetate in the desired weight ratio. Also, to control the growth of ZnO nanostructures, chloride ions were used as a capping agent. The X-ray diffraction (XRD) pattern confirmed the influence of chloride ion concentration on the growth of ZnO nanostructures. Field emission scanning electron micrographs (FE-SEM) of as-deposited samples showed the formation of uniform and defect free ZnO–PVA composite nanofibers and the calcined samples revealed the growth of nanospherical and pencil like nanorod shaped ZnO. The growth mechanism, electrical characteristics as well as the room temperature ethanol sensing characteristics of the calcined ZnO nanostructures were investigated. The influence of morphology, grain and grain boundary resistances, activation energy of ZnO nanostructures and dissociation bond energy of ethanol molecules on the receptor and transduction functions of ZnO sensing elements has been discussed.