Preparation, Characterization And Properties Of Silver/Copper Nanostructures

Basing on the investigations on the preparation and ion conductive properties of RbAg4I5 and CuI fast ionic conductor films, we devised a solid-state ionics method to synthesize silver and copper nanostructures. In this process, RbAg4I5 film and CuI film were employed as the media for transmitting silver and cuprous ions, respectively. Controlled synthesis of metal nanostructures could be achieved by adjusting the applied electric field strength. Centimeter-scale long well aligned metal nanowire ribbons were also prepared with this method.After subsequent experiments, we got a set of parameters to the preparation of film by vacuum thermal evaporation. Pure RbAg4I5 fast ionic conductor films were prepared when we use NaCl or quartz glass as substrates. Pure CuI fast ionic conductor films could also be prepared on quartz glass substrates. AFM, SEM, TEM, XRD, XPS and absorption spectrum were employed to characterize the films, including their morphologies, crystal structures and components. Electrical measurements were also carried out. Results show that at room temperature the ionic conductivities of RbAg4I5 fast ionic conductor film is 0.12?-1cm-1 on a NaCl substrate, while 0.07?-1cm-1 on a quartz glass substrate; at 80°C the conductivities of CuI film is 8.3×10-3?-1cm-1 on a quartz glass substrate.If we use two pieces of silver (copper) films as electrodes, RbAg4I5 (CuI) film as the medium for transmitting silver (cuprous) ions, silver (copper) nanostructures could be prepared when a direct current electric field was applied. Metal nanostructures with different morphologies, such as nanowire arrays, nanotube arrays and nanoparticle arrays, could be prepared in different electric field strength ranges. In the range of preparing metal nanowires, when slightly change the field strength, we can control the arrangement of the nanowires. When we use an optical fiber as substrate for RbAg4I5 film, centimeter-scale long silver nanowire ribbons with large aspect ratio were prepared. Further more, we found the temperature played an important role in influencing the morphology of the nanowires; I think thisphenomenon is of great help to the controlling synthesis of metal nanowires. Investigation on the nanostructures indicates the products are single crystal with a face center cubic structure.Research on well-aligned silver nanowire ribbons indicates that they have obvious characteristic of reflective polarization; The fluorescence of central wavelength at 500nm could be got when the silver nanowire ribbon was excited by two photon at 730nm; When the ribbon was used as the surface-enhanced Raman scattering substrate,Raman spectrum of R6G solution as low as 10-12mol/L in concentration could be detected; It also can enhance fluorescences of FITC-IgG solution and biological cell of labeled FITC-IgG; as substrate, it can catalyse biological reaction of firefly fluorescence.