Controllable growth of ZnO nanostructures by citric acid assisted hydrothermal process

The disk-like, flower-like and nanorod flower-like ZnO nanostructures have been controllably fabricated by citric acid (CA) assisted hydrothermal process. All the ZnO nanostructures are hexagonal and single crystal in nature. The effects of the growth conditions such as temperature, pH value and the molar ratio of Zn2+ and CA on the morphology of ZnO nanostructures have also been investigated. It is considered that CA has a critical role in the formation of disk-like ZnO nanostructure. The pH value is the main factor to determine the anisotropic growth. The blue shift in the ZnO nanostructures is observed. Finally, the mechanism for CA assisted hydrothermal synthesis of the ZnO nanostructure is discussed.