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 °C. The diameters of ZnO microspheres with narrow size distribution ranging (<8%) can be tuned from ∼670 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.