Impact of rGO Concentration on the Physical Characteristics of CuO/rGO Nanocomposite for Sensing and Optoelectronic Applications

Abstract

Facile synthesis demonstrated formation of CuO/rGO composite for enhanced optical and electrical characteristics for sensing and photonic devices. CuO nanoparticles synthesized using sol-gel method and various rGO percentages (10%–30%) were loaded to form composite via ultra-sonic assisted technique. Structural study using XRD and TEM confirms the formation of CuO polyhedral nanoparticles with monoclinic structure showing deviations in the unit cell parameters, crystallite size, axis strain. These deviations cause transformation of polyhedral particles into rod shaped nanocomposites with embedded CuO single crystals with changed rGO. X-ray photoelectron spectroscopy showed varied elemental composition of CuO/rGO nanocomposites having Cu2+ chemical state. Optical measurements exhibit modified direct (1.54 eV–1.51 eV) and indirect bandgap (1.38 eV–1.31 eV) having higher absorption in Visible to NIR region for photovoltaic applications. Raman spectroscopy and FTIR confirms the presence of Raman active bands and functional groups corresponding to Cu-O. Electrical measurements shows decreased resistance with increased incorporation of rGO. The higher presence of oxygen sites and low resistance facilitate easy electron transport alongwith an optimum bandgap (1.51 eV) and higher absorption in Visible to NIR region showed possible utility of the grown nanoparticles and composites in gas/photo sensing and optoelectronic applications.