Temperature Dependence on Structural Properties of Liquid Phase Synthesized ZnO

Abstract

Transparent conducting oxide material, ZnO nanoparticles has been synthesized using inexpensive and eco-friendly synthesis procedures with less or environmental pollutants and no liquid waste products. The effect of the temperatures on the structural properties for the synthesized ZnO nanocrystals has been investigated. In this study, we report an easy, low-cost, re-producible method for synthesizing ZnO nanoparticles by means of the liquid phase method. The ZnO nanocrystals were synthesized using the wet chemical route and the effect of temperature variation on the structural properties of investigated synthesized using powder x-ray diffractogram (XRD). The temperatures for the synthesis were varied from 120 °C to 200 °C in steps of 20 °C. The results show that, during the first stage of the synthesis of ZnO (at 120 °C), the XRD diffraction pattern confirms the cubic structure of zinc peroxide and the XRD pattern of the samples obtained at temperatures of 140 °C, 160 °C, 180 °C and 200 °C were confirmed to be hexagonal (wurtzite) crystal structure of ZnO. The XRD diffraction patterns of the 140 °C and 160 °C samples show some impurity phases which were associated with the zinc acetate by-product which is a colloid complex of water and methyl succinate and were removed by evaporation as temperatures were increased to 180 °C and 200 °C respectively. As temperature increases, the peak of the diffractograms of the sample becomes sharper and narrow indicating a decrease in width. A shift in peak positions to higher angles was observed and the positional parameter, bond angle, β, average crystallite size, APF, number of unit cells and density generally increase with temperature. However, the lattice parameters ‘a’ and ‘c’, bond lengths b and b1, bond angle, α, dislocation density, strain and unit cell volume were found to generally decrease with temperature.