Two step synthesis of ZnO/Ag and ZnO/Au core/shell nanocomposites: Structural, optical and electrical property analysis

In this work, based on the two-step synthesis ZnO/Ag and ZnO/Au core/shell nanocomposites (CSNCs) were developed and reported the structural, optical and electrical properties. The core material of the ZnO nanoparticles (NPs) was prepared by a simple hydrothermal route, where sodium hydroxide (NaOH) acts as reducing agent. In the ZnO/Ag and ZnO/Au CSNCs material, Ag and Au NPs act as the shell material and used for subsequent nucleated growth on the surface of ZnO NPs by using cationic surfactant Cetyl Tri-methyl Ammonium Bromide (CTAB). The FCC structure for Ag and Au material and the hexagonal wurtzite structure for ZnO material were analyzed by Powder X-ray Diffraction (PXRD) analysis. The presence of oxygen vacancies and Zn interstitials were confirmed by FT-Raman analysis and the functional groups were identified by Fourier Transform Infrared Spectroscopy (FTIR) analysis. The structural defects and charge distribution of the ZnO/Ag and ZnO/Au CSNCs was studied by Photoluminescence (PL) spectroscopy. The morphological studies of ZnO/Ag and ZnO/Au CSNCs were determined by using TEM analysis. The low value of dielectric constant and the dielectric loss obtained in both the material shows that the materials can be used for the various electronic device fabrication and also a small amount of activation energy observed for a higher frequency from ac conductivity measurements supports the materials to be used for the various electro-optic applications. (C) 2018 Elsevier B.V. All rights reserved.