Structure and Optical Behavior of Nanocomposite Hybrid Films of Well Monodispersed ZnO Nanoparticles into Poly (vinylpyrrolidone)
Structure and Optical Behavior of Nanocomposite Hybrid Films of Well Monodispersed ZnO Nanoparticles into Poly （vinylpyrrolidone）

We fabricated an inorganic-polymeric photoluminescent thin film based on ZnO nanoparticles, which were grown directly in the poly(vinylpyrrolidone) (PVP) matrix. The microstructure, composition, thermal stability,and the temperature-dependent photoluminescence of the thin film were investigated. X-ray diffraction (XRD)and transmission electron microscopy (TEM) results indicated that all the ZnO nanoparticles with a polycrystalline hexagonal wurzite structure were well separated from each other and were dispersed in the polymeric matrix homogeneously and randomly. Raman spectrum (Raman) showed a typical resonant multi-phonon process within the hybrid thin film. The shifts of infrared bands for PVP in the hybrid film should be attributed to strong coulombic interaction between ZnO and polymeric matrix. The stability of the hybrid film and the effect of the perturbation of ZnO on the stability were determined by means of the thermogravimetric analysis (TG) and differential thermal analysis (DTA). The ultraviolet-visible adsorption (UV-vis) showed distinct excitonic features. The photoluminescent spectrum (PL) of the ZnO nanoparticles modified by PVP molecules showed markedly enhanced ultraviolet emission and significantly reduced green emission, which was due to the perfect surface passivation of ZnO nanoparticles. Temperature dependent photoluminescent spectrum studies suggested that the ultraviolet emission was associated with bound exciton recombination.