Cavity of cyclodextrin, a useful tool for the morphological control of ZnO micro/nanostructures

Micro/nanostructures of ZnO with different morphologies were successfully prepared by using β-cyclodextrin (β-CD) as a crystallization modifier, at relatively mild conditions. The as-prepared products were characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The effects of β-CD concentration, the reaction time and temperature on the final morphologies of ZnO crystals were discussed. The results showed that the β-CD concentration and reaction time played an important role for the morphological change of ZnO crystals. Additionally, the cavities of β-CD molecules were underlined in the process of ZnO crystallization. On the basis of the multiple functions of β-CD molecules, we proposed a possible mechanism for the morphological evolution of various ZnO crystals.