Precursor induced synthesis of hierarchical nanostructured ZnO

Abstract

As-synthesized ZnO nanostructures with a bladed bundle-likearchitecture have been fabricated from a flower-like precursorZnO·0.33ZnBr2·1.74H2O via a mechanism of dissolution–recrystallization. Experimental conditions, such as initial reactantsand reaction time, are examined. The results show that no bladed bundle-like ZnO hierarchicalnanostructures can be obtained by using the same molar amount of other zinc salts, such asZnBr2, instead ofthe flower-like ZnO·0.33ZnBr2·1.74H2O precursor, and keeping other conditions unchanged. The products werecharacterized by field emission scanning electron microscopy (FE-SEM) andtransmission electron microscopy (TEM). The ZnO nanostructures are mainlycomposed of nanowires with a diameter around 40–50 nm and length up to1.5–2.5 µm. Meanwhile, ZnO nanoflakes with a thickness of about 4–5 nm attached to the surface ofZnO nanowires with a preferred radially aligned orientation. Furthermore, thephotoluminescence (PL) measurements exhibited the unique white-light-emittingcharacteristic of hierarchical ZnO nanostructures. The emission spectra cover the wholevisible region from 380 to 700 nm.