Morphology Controlling of ZnO Sub-Micron- and Micro-Structures from Sub-Micron Zinc Citrate Precursor.

A wet-chemical route has been demonstrated to investigate the morphology evolution of high crystalline ZnO sub-micron- and micro-structures created from a zinc citrate precursor consisted of zinc citrate nanoparticles. The concentrations of precursor zinc citrate and the addition of trisodium citrate were key factors in the controlling of ZnO micro-morphology. Assembled growth resulted in the formation of ZnO sub-micron- and micro-structure with twin-cone and flower-like morphologies. The ZnO flower was consisted of cone petals. The shape of ZnO microstructures was further adjusted using trisodium citrate to created thin and thick hexagonal-plates. In the case of a high Zn concentration, thick hexagonal-plates were split into a flower-like morphology. The investigation of morphological evolution indicated that trisodium citrate is critical to control the growth rate of polar (0001) plane. The formation of a flower-like structure is ascribed to the assembly of crystal units with a high zinc citrate concentration.