Selective synthesis and characterization of flower-like ZnO microstructures via a facile hydrothermal route

Flower-like ZnO microstructures with an average diameter of 1 μm assembled from nanorods have been successfully synthesized via a facile hydrothermal method under mild conditions using aqueous zinc nitrate as zinc source, sodium hydroxide as precipitating reagent and triethylamine (TEA) as both alkaline and complexing reagent. The influences of hydrothermal temperature, reaction time, and concentration of NaOH and TEA on the morphology and size of final products have been carefully investigated. The phase structures, morphologies and optical properties of the final products were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscope (HRTEM), and photoluminescence (PL) and UV–vis absorption spectrometer. The probable formation mechanism was also proposed based on the experimental results. The photoluminescence characterization of flower-like ZnO microstructures exhibited a blue emission at 465 nm and a broad visible emission in green region and a red-shift was observed in their UV–vis absorption spectrum.