Influence of graphene oxide on the dielectric properties of biogenically synthesized ZnO nanoparticles

Abstract

This study presents a novel and biogenic route to synthesize zinc oxide (ZnO) nanoparticles using Phoenix dactylifera fruit extract as a plant-mediated reducing agent. Graphene oxide (GO) was synthesized using the improved Hummer's method, and a series of GO-ZnO nanocomposites were produced by the ultrasonic-dispersion method. The structural and optical properties of the nanocomposites have been analyzed using XRD, TEM, FESEM-EDX, UV-vis. DRS, and FTIR spectroscopy. The results indicate that ZnO nanoparticles are deposited over GO sheets in the nanocomposites. The structural analysis and Rietveld refinement confirmed the successful synthesis of crystalline single-phase ZnO nanoparticles with a hexagonal-wurtzite structure. The influence of GO on the dielectric properties of green-synthesized ZnO nanoparticles was analyzed in the frequency range 20 Hz-2 MHz at ambient temperature. The results showed a significant increase in the dielectric constant and ac conductivity with growing GO content in the nanocomposites compared to that of pristine ZnO. Complex impedance analysis revealed the non-Debye type relaxation and a decreasing trend in the complex impedance value with increasing GO content. This novel biogenic synthesis approach is energy-efficient and environment-friendly, which can provide an effective route for low-cost and scaled-up production of nanocomposites for several applications.