Large-scaled, uniform, monodispersed ZnO colloidal microspheres

Large-scaled and monodispersed ZnO microspheres have been prepared successfully by using triethanolamine (TEA) aqueous solution as solvent at low reaction temperature ranging from 150 to 200 degrees C. The diameters of ZnO microspheres with narrow size distribution ranging (< 8%) can be tuned from similar to 670 to similar to 1150 nm only by changing the reaction temperature, and each ZnO microsphere is composed of numerous ZnO aggregates nanocrystallines with diameters of 16.4-21.9 nm. A mechanism for the formation of ZnO microspheres has been proposed, in which TEA plays a crucial role in the formation of the wurtzite ZnO microspheres. Room-temperature photoluminescence spectra of the ZnO microspheres reveal a strong emission peak at 391 nm and several weak emission peaks at 420, 484, and 530 nm, respectively.