Aggregation-induced growth of hexagonal ZnO hierarchical mesocrystals with interior space: nonaqueous synthesis, growth mechanism, and optical properties

A facile method is reported for the manipulation ZnO nanocrystals into hierarchical mesocrystalline ordered structures with interesting interior space morphology. The unique structures determined by field emission scanning electron microscopy (FESEM) showed that the as-prepared ZHMI is composed of many folds with a stable step, and the steps spontaneously align with one another to form a regular hexagonal interior cavity with a width of similar to 1.5 mu m and angles of about 120 degrees. The building of the ZnO hierarchical mesocrystals with interior space (ZHMI) was correlated to a nonclassical crystallization pathway. An aggregation-induced fast crystal growth mechanism was proposed to explain this novel growth mode. For a better understanding of the ZHMI formation process, the structure of ZHMI was analysed by XRD, FESEM and TEM. Finally, the relationship between the optical properties and the structural evolution of the ZHMI was described. It was found that the diffuse reflectance of the ZHMI is superior to other structural ZnO, showing the better light scattering ability of ZHMI.