Green and chemically synthesized ZnO nanoparticles: A comparative study

Abstract

Green synthesis of ZnO nanoparticles using plant extract is an alternative method to traditional chemical synthesis method. In the present work, we report the synthesis of zinc oxide nanoparticles (ZnO) synthesized by two methods, first by green synthesis by using zinc acetate and leaves extract of Ocimum Tenuiflorum (Tulsi leaves) and secondly by chemical route method using organic capping agent. The effect of synthesis methods on structural, optical, and photoluminescence property of ZnO nanoparticle were analyzed. Formation of zinc oxide nanoparticles has been confirmed by UV-Visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The Scanning Electron Microscope reveals non spherical morphology of nanoparticles. The particle sizes of nanoparticles were calculated experimentally using XRD and SEM. The particle size measured by XRD pattern was found to be 63nm for chemically synthesized ZnO and 38nm for ZnO sample prepared by green synthesis. SEM images showed interesting flower like structure and agglomeration of nanoparticles. The blue-shift in absorption spectra was observed with reducing size of the nanoparticles. The FTIR spectra inferred that the stabilizing agent passivated the surface of the particles. The PL spectra showed blue shift for the sample prepared by green synthesis. The results suggest that ZnO sample synthesized be green route is better in comparison to the chemically synthesized samples.