Oriented growth of urchin-like zinc oxide micro/nano-scale structures in aqueous solution

The urchin-like ZnO microcrystals with high crystallinity decomposed from [Zn(OH)4]2− directly were obtained via a hydrothermal method. The morphology, particle size, crystalline structure and fluorescence of the as-prepared ZnO were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) analyses. The results demonstrated that the urchin-like ZnO crystals with wurtzite structure had a narrow distribution in size, which could be adjusted in the range of 30–80 μm by varying reaction time. Broad visible light emission peak was also observed in the PL spectra of the synthesized ZnO products. A multistep growth process about how to form such a structure was proposed.

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► Highly oriented and well-defined ZnO urchin-like crystals were successfully fabricated by a facile and effective hydrotherm method.
► Polyvinylpyrrolidone- and hydrogen peroxide-assisted synthesis of ZnO could optimize its crystalline quality and the obtained ZnO have smooth surface, radial growth of morphology, obvious crystal edges and decreased defects.
► The physicochemical properties of samples were studied by analysis of its structure, morphology, surface and optical properties.
► This study represented a multistep mechanism based on [Zn(OH)4]2− growth units about formation such urchin-like structure.