Hydrothermal growth of center-hollow multigonal star-shaped ZnO architectures assembled by hexagonal conic nanotubes

Three-dimensional (3D) center-hollow multigonal star-shaped ZnO architectures have been successfully fabricated on a large scale using Zn(acac)2 (acac = acetylacetone) and ethylenediamine as starting reactants via a surfactant-assisted hydrothermal process. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images show that the 3D multigonal star-shaped ZnO architectures are center-hollow, which are composed of hexagonal conic nanotubes. Room temperature photoluminescence spectrum shows a sharp and strong UV band-edge emission at 387 nm and a weak broad green emission around 534 nm. The contrastive experimental results indicate that the introduction of surfactant poly(vinylpyrrolidone) (PVP) or polyethylene glycol (PEG) is indispensable in controlling the growth of multigonal star-shaped ZnO with hollow structure. A so-called “soft-template-mediated growth” mechanism was proposed for the formation of ZnO hollow star.