3D flowerlike ZnO micro-nanostructures via site-specific second nucleation in the zinc–ethylenediamine–hexamethylenetetramine tertiary system

Three-dimensional flowerlike ZnO micro-nanostructures were fabricated from aqueous solution in the zinc–ethylenediamine (EDA)–hexamethylenetetramine (HMT) tertiary system at relatively low temperature (95 °C) in 2 h, via selective adsorption and site-specific second nucleation of EDA and selective adsorption of growth units. The obtained ZnO micro-nanostructures exhibit well-defined flowerlike morphology, hexagonal wurtzite structure and strong UV photoluminescence. The petals, which present hexagonal pyramidal feature, are single crystal and preferentially growing along the [0 0 0 1] direction. Effects of EDA, HMT, concentration and temperature were investigated. It shows that the EDA is crucial to the formation of 3D flowerlike ZnO by selective adsorption and site-specific second nucleation, and both EDA and HMT have an effect on the petal morphology. Moreover, lower concentration leads to smaller size of product and lower temperature makes nuclei liable to aggregate. In addition, the growth process of 3D flowerlike ZnO was also discussed.