Study On Synthesis And Optical Properties Of ZnO-Au And ZnSe-base Hybrid Nanocrystals

Hybrid nanocrystals (HNCs) are structurally elaborated multimaterial nanocrystals, consisting of two or more chemically different material sections interconnected through permanent inorganic interfaces. As compared with single phase nanocrystals, HNCs exhibit distinct properties such as enhanced photoluminescence, modified magnetic behaviors and improved photocatalystic responses. Moreover, asymmetric HNCs (e. g. nanodimers, nanotrimers) could serve as bifunctional or multifunctional materials.In this thesis,appropriate route for ZnO-Au Hybrid nanocrystals (HNCs) was obtained by comparing reverse microemulsion, aqueous chemical methods and high temperature reflux. ZnO-Au hybrid nanocrystals with good dispersibility and uniform size are prepared via a high temperature reflux route. The structure, morphology, interface structure and optical properties were characterized by X-ray diffraction high resolution transmission electron microscope and UV-vis absorption spectrophotometer. The formation of hybrid nanocrystals was believed to arise from the heterogeneous nucleation and epitaxial growth, high temperature and surfacantant are proposed as the key factors for producing fine and uniform hybrid nanocrystals. As compared with pure ZnO, the hybrid nanocrystals exhibit strong visible light emission arising from the defects at the ZnO-Au interface and good photocatalytica properties.Different ZnSe-based HNCs was prepared via high temperature reflux route. The photoluminescence of ZnSe-Au was quenched because there are interfacial defects between ZnSe and Au nanocrystals. Meanwhile, Photoluminescence wavelength of ZnSe nanocrystals was modified by preparing ZnSe-Ag2Se HNCs.ZnO-ZnSe is promising type-Пsemiconductor. In this thesis, ZnSe-ZnO HNCs was prepared via high temperature reflux.