Precursor induced synthesis of hierarchical nanostructured ZnO

As-synthesized ZnO nanostructures with a bladed bundle-like architecture have been fabricated from a flower-like precursor ZnO·0.33ZnBr2·1.74H2O via a mechanism of dissolution-recrystallization. Experimental conditions, such as initial reactants and reaction time, are examined. The results show that no bladed bundle-like ZnO hierarchical nanostructures can be obtained by using the same molar amount of other zinc salts, such as ZnBr2, instead of the flower-like ZnO·0.33ZnBr2·1.74H2O precursor, and keeping other conditions unchanged. The products were characterized by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The ZnO nanostructures are mainly composed of nanowires with a diameter around 40-50 nm and length up to 1.5-2.5 μm. Meanwhile, ZnO nanoflakes with a thickness of about 4-5 nm attached to the surface of ZnO nanowires with a preferred radially aligned orientation. Furthermore, the photoluminescence (PL) measurements exhibited the unique white-light-emitting characteristic of hierarchical ZnO nanostructures. The emission spectra cover the whole visible region from 380 to 700 nm