Study On The Chemical Preparation And Enhanced Fluorescence Properties Of Different Shapes Of Silver Nanoparticles Assisted By AAO Template

Metal nanomaterials have extensive potential applications in nanoelectronics, optics,electromagnetism,sensor and biological imaging.The unique physical and chemistry properties of metal nanoparticles are strongly depended on their size and shape.Therefore,the preparation of metal nanoparticles with controllable size and shape attracts extensive attentions.At present,although there are varieties of synthesis methods,all of them have some drawbacks.Based on the research on synthesis of Ag nanoparticles,this dissertation presents a facile,well repetitive chemical method assisted by Anodic Alumina Oxide(AAO) template to prepare silver nanoparticles with various morphologies.It makes exploratory and experimental research on the application of Ag nanoparticles in metal-enhanced fluorescence(MEF).The main results and conclusions are outlined as follows:1.It explores the pretreatment process of the anodic alumina,oxide(AAO). Homogeneous and ordered anodic alumina oxide(AAO) with average diameter of 60nm was fabricated by twice-anodic oxidation method.The research indicates that the most suitable experimental conditions are as follows:the oxidation constant current is 0.06A and the concentration of oxalic acid is 0.3mol/L.Both of the anodic oxidization time is 4h.The optimum pore-widening time is 20 minutes to 30 minutes.2.Dendritic nanostructure silver is synthesized on the surface of AAO which is used as carrier by electrochemical deposition.The results indicate that the trunk length of the dendritic structure can reach a dozen even dozens of micrometer and the branch is clear and parallel.The product is readily separated because it is produced on the surface of AAO.3.With the assist of AAO,silver nanoparticles with various morphologies are synthesized by solvothermal method using ethylene glycol(EG) and N,N-dimethylformamide(DMF) as reductant separately.Results show that when we use EG as reductant,the introduction of AAO as a heteromesic facies is favorable to the formation of one-dimensional silver nanoparticles on the surface of AAO.When using DMF as reductant,Polyvinylpyrrolidone K30(PVP K30) is added into the reaction solution.The reaction product mainly consists of one-dimensional silver nanoparticles as well as triangular,chamfer triangle and hexagonal nanoflakes.The unique structure of AAO can make PVP reaching its critical micelle concentration on the surface of AAO easily which leads to the formation of one-dimensional silver nanomires in shorter time.4.Ag nanograins and silver nanowires obtained by centrifuged,are deposited on the glass substrate and AAO separately.The effect of product on the fluorescence property of Rhodamine B is studied.The results indicate that more obvious enhanced fluorescence phenomenon can be observed from the Ag nanowires deposited on the AAO than that on the glass substrate.But the enhanced factor is lower than the Ag nanowires deposited on the glass.However,the enhanced factor of Ag nanograins on the AAO is higher than that deposited on the glass.