Sunlight-assisted fabrication of a hierarchical ZnO nanorod array structure

Abstract

A ZnO hierarchical structure built up of a well ordered nanorod array was obtained by a simple treatment of zincate ion aqueous solution and a zinc foil mixture with sunlight irradiation. The as-prepared ZnO nanorods are all single crystalline with a uniform [0001] preferential growth direction and have an average diameter of approximately 40 nm and a length of approximately 300 nm. It is believed that sunlight gave rise to the driving force for the preformed ZnO nanorod to self-assemble into plates, which served as the substrate for secondary heterogeneous nucleation, and subsequently the crystal growth resulted into formation of a ZnO nanorod array. The formation mechanism of the ZnO hierarchical nanorod array structure was discussed, based on controlled experiment results. Raman spectroscopy, cathodoluminescence and UV-Vis absorbance spectra of the as-prepared ZnO product have been performed.