Controlled Growth of ZnO Nanoparticles with Different Morphologies Using Sol-Gel Technique

Abstract

A low temperature sol-gel approach was demonstrated to prepare ZnO nanoparticles with controlled morphologies. By changing the concentration of NH4OH, the ZnO nanoparticles evolves from sphere-like, star-like and sheet-like structures. No peak of additional phase was observed in the XRD patterns except the diffraction peaks of ZnO. The estimated crystallite size of ZnO nanoparticles decreases with the increase of NH4OH. It is also found that the morphology of nanoparticles affects the optical bandgap of ZnO. The optical bandgap of sphere-like,star-like, and sheet-like ZnO nanoparticles are 3.55 eV, 3.48 eV and 3.45 eV, respectively. The growth mechanism of ZnO nanoparticles was discussed.