Optical and structural properties of zinc oxide nanoparticles synthesized by different sol-gel routes

Abstract

Transformation into nanoscale from bulk structures involves an outstanding modification in the properties of materials. It gives an opportunity to get a novel behaviour such as size dependent in structural and optical properties. Zinc oxide nanoparticle is a promising material for many applications especially optical devices. There are many methods to synthesis these nanoparticles. In this work ZnO nanoparticles are synthesized by sol-gel method using different routes with different stirring temperatures. The structural, morphological and optical properties of ZnO nanoparticles are studied. The result of the XRD shows that the average particle size of ZnO particles decreases with increasing stirring temperature. By using Williamson-Hall formula to calculate the average size of ZnO nanoparticles it reveals that the Zinc Acetate precursor gives smaller nanoparticles than Zinc Nitrate (at 70 o C ~22 and ~50 nm respectively). FESEM images display the semi-spherical shaped of the synthesized nanoparticles and emphasise that the nanoparticles synthesized by Zinc Acetate are finer and more homogenous than those synthesized with Zinc Nitrate. Furthermore, the photoluminescence result shows that the band energy of the zinc oxide nanoparticles synthesized by Zinc Nitrate is 3.02 eV while for those synthesized with Zinc Acetate is 3.10 eV. The excellent features of the result suggest that this work may constitute a basis for the tuneable synthesis of ZnO nanoparticles suitable for optoelectronics devices.