Controlled synthesis of ZnO spheres using structure directing agents

Abstract

Controlled liquid phase deposition has been developed for fabricating zinc oxide (ZnO) nano/microspheres using a mixture of precursor solution of zinc acetate dihydrate, ammonium hydroxide, and structure directing agents (SDAs) such as ethanol and urea. We found that ZnO spheres can be formed when the SDAs are optimized with the proper pH values. At pH values less than 12, an anisotropic growth of ZnO flowers and rod structures was produced with/without SDAs. On the contrary, at a pH value of 12 the directional growth of ZnO was absolutely controlled and an isotropic growth of ZnO spheres was developed with the presence of SDAs. We also found that the volume ratio of ethanol and urea in the solution was a key factor to modulate the uniform size distribution and diameter of the ZnO spheres from nanometer to micrometer range. (C) 2013 Elsevier B.V. All rights reserved.