Self-assembly of ZnO nanoplates into microspheres

The fabrication of ZnO micropheres self-assembled by single-crystal nanoplates using ZnC2O4 as a precursor was investigated. The precursors of hydrous zinc oxalate were obtained through dissolving 3 mmol of ZnCl2 and 3 mmol of Na2C2O4 in 30 mL distilled water under constant magnetic stirring for 10 min. The precipitates obtained were filtered, washed with distilled water, and dried. The X-ray powder diffraction (XRD) patterns of the products were recorded on a Philips X' pert X-ray diffractometer. All the diffraction peaks of the XRD pattern could be indexed to a pure hexagonal phase of ZnO with lattice constants a = 0.325 nm and c = 0.521 nm. The strong and clear diffraction peaks reveal good crystallinity of the as-obtain product. Due to their good crystallinity, photoluminescence properties, and high specific surface area, the product can be used in studies considering the effects of spatial orientation and arrangement of 2-D nanoscale building blocks.