Controllable synthesis of ZnO nanostructures by a simple solution route

Flower-shaped ZnO nanostructures, composed of ZnO nanorods, and sphere-shaped ZnO nanoclusters, composed of ZnO nanosheets, were synthesized by reacting zinc acetate dehydrate with sodium hydroxide and polyethylene glycol-20000 (PEG-20000) at 180 °C for 4 h in solution. The thickness of individual nanosheets is about 40-60 nm. The nanorods are of hexagonal shape with sharp tips, and have basic diameters of ca. 450-550 nm. The ZnO nanostructures were characterized by scanning electron microscropy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared, and Raman scattering measurements. The results demonstrated that the synthesized products are single crystalline with wurtzite hexagonal phase, the sphere-shaped ZnO grew in the [100] direction and the flower-shaped ZnO grew in the [001] direction.