CTAB-facilitated ex-situ synthesis of chitosan-based ZnO, CuO, and ZnO/ CuO nanocomposites for improved optical emission

The present investigation deals with the synthesis and characterization of CTAB assisted pristine ZnO, CuO and ZnO/CuO nanoparticles and their corresponding chitosan based nanocomposites. The XRD and FTIR results reflect the successful formation of pristine nanoparticles as well as their chitosan nanocomposites. The X-ray photoelectron spectroscopy (XPS) study confirms the tagging of chitosan by revealing the presence of element nitrogen which is expected to be derived from the chitosan biopolymer itself. The optical investigation reveal the bandgap energy of the pristine ZnO, CuO and ZnO/CuO nanoparticles to be 3.2, 1.95 and 2.60 eV, respectively. The interaction of chitosan with the pristine samples bring in changes in the bandgap energy due to alterations in energy band structure. The photoluminescence (PL) studies also clearly indicate the improved optical and electronic property of the composites on addition of chitosan by introducing defects in the crystal structure.