Preparation And Property Of Silver Nanowires Flexible Transparent Conductive Films Via Self-Assembly

Silver nanowires(Ag NWs) that can be controllably synthesized in large quantities, have the merit to be fabricated to transparent conductive films through solution process using various methods. Ag NW films not only exhibit similar or even better optoelectronic performance than ITO, but also own the advantages of flexibility and stretchability that ITO lacked. Hence Ag NWs have become one of the most promising ITO alternatives. In this thesis, Ag NWs with different aspect ratios were synthesized by modified polyol reduction approach and hydrothermal process. According to their special one-dimensional(1D) structure, Ag NWs were fabricated into transparent conductive filmsby self-assembly method and their photoelectric properties was comprehensively studied. The asprepared Ag NW transparent conductive films was successfully applied as anode for organic solar cells. The main progresses are summarized as follows:1. Ag NWs with three different aspect ratios(100, 400, 1000) were synthesized in control, with the same diameter of 50 nm. Evaporation-induced assembly was utilized, combining with dip-coating, for achieving aligned Ag NW arrangement in one direction. By further second dip-coating in the perpendicular direction, Ag NW crossing network film was achieved. After comparison of the assembly of the different type of Ag NW, it can be demonstrated that, the dip-coating method was appropriate for the Ag NW with shorter aspect ratio, because Ag NW with high aspect ratio tended to aggregated into bundles during assembly. The transparent conductive film fabricated by shorter Ag NW exhibited excellent photoelectric properties, sheet resistance of 35 Ω sq-1 and transmittance of 92%, and could be applied in the solar cell as anode, the PCE of device could reach 2.83%.2. The bubble consisted of air- surfactant- water, formed by surfactant in water system, served as the template, and Ag NW were dispersed in the water phase. A “sandwich” structure, where Ag NW in the solution self-assemblied, was constructed by glass and PET with foam. The foam film was fast freezed to fix the pore structure of the foam formed, Ag NW porous film was finally achieved by freeze-drying. The concentration of the surfactant had influence on foam stability and bubble size, which further influenced the pore size of the film. The density of Ag NW in the film was tuned by adjusting the distance of two substrates.