Surface plasmon enhanced near-UV emission in monodispersed ZnO:Ag core-shell type nanoparticles synthesized by a wet chemical method

摘要

Monodispersed core-shell type ZnO:Ag nanoparticles were synthesized by a wet chemical method and their salient properties were reported. The synthesis technique explores a facile route following a chemical reaction between aqueous solutions of poly-vinyl alcohol (PVA), sucrose and Zn~(2+) salt. The Zn~(2+)-PVA-sucrose polymer precursor powders so obtained after the reaction was further explored for the synthesis of ZnO:Ag nanoparticles. The key part of the process lies in the use of polymer encapsulated ZnO nanoparticles as templates to obtain the ZnO core-Ag shell type nanostructures. Structural, morphological and optical properties of the derived ZnO:Ag core-shell nanoparticles were evaluated with X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, and photoluminescence (PL) spectroscopy. Microstruc-tural analysis revealed monodispersed platelet shaped ZnO nanoparticles with a thin layer of Ag coating on the surface. The surface modified ZnO nanoparticles show colossal enhancement in their near-UV emission characteristics, primarily due to the efficient excitation of surface plasmons and excellent semiconductor-metal interfacing in the ZnO:Ag nanoparticles.