Uniform nano/micron-sized ZnO spheres with controllable diameter

Novel uniform nano/micron-sized ZnO spheres assembled from the aggregation of nano-particles have been synthesized by hydrothermal method. It was observed that ZnO spheres with controllable diameter were obtained when various volume ratios of triethanolamine (TEA) to H2O were used. Increasing the volume ratio of TEA to H2O could result in the formation of loosely packed ZnO spheres. The UV-visible absorption spectra show that the absorption peak red-shifts with the increasing average diameter of the spheres.