Study On The Synthesis And Shape Controlling Of Silver Nanostructure

Nanomaterial refers to superfine material graining size level of Nanometer (10-9meters). Theparticle size (the general size is100nm) is larger than the atomic clusters and smaller than the usualparticles. Nanomaterial presents the unique physical and chemical properties due the fundamentaleffects, such as small size effect, quantum effect, surface effect, quantum tunneling effect et al. Noblemetal nanomaterials with unique chemical and physical properties have extensive applications inelectronics, optics, sensor and biomedical. And the properties and applications are closely related withtheir size and shape. Therefore, it is believed that property-controllable of metal nanoparticles andfurther designing functional nanodevices will be conveniently realized by tuning their morphologies,sizes, dimensionalities and compositions.Silver nanostructures were the research object in this dissertation. In the first part, we preparedtriangle silver nanoplates through photochemistry method, followed by disscussing growthmechanism. Then, silver nanodisks with nearly uniform size were prepared using reduction method,and influence of experimental parameters on the morphology of final products was studied. In thethird part, silver nanowires were prepared using hydrothermal method and assemblied with theaddition of THF.The main research and results of this dissertation are outlined as follows:1. The preparation of triangular silver nanoplates. Using light induced method, silver nitrate asprecursor, trisodium citrate as reducing agent and surfactant, we synthesized triangular silvernanoplates. UV-Vis spectroscopy, TEM, SAED, XRD were used to characterize their nanostructureand shapes. The effects of experimental reagents on the products were further studied. It is found thatthe addition of excessive trisodium citrate was useful for the formation of silver nanoplate, anddissolution and growth co-existed during the formation of silver nanoplates.2. The preparation of disk silver nanoplates. Using rapid reductive deposition method, silvernitrate as precursor, ascorbic acid as reducing agent, trisodium citrate as surfactant, silver nanodiskswith nearly uniform size (~25nm) were produced. Influence of experimental parameters (such aspreparation method of seed, concertrations of reducing agent and surfactant.) on the morphology ofproducts was investigated. It is found that trisodium citrate is nessary in the synthesis of seeds, whilesilver nanodisks can be obtained without the addition of trisodium citrate.3. The preparation and self-assembly of silver nanowires. Using hydrothermal method, silver nitrate as precursor, ethylene glycol as reducing agent, PVP as surfactant, we synthesized highlypurified silver nanowires. Growth mechanics of silver nanowires, involving the effects of PVP andHCl, were proposed. Then, we explored the effects of experimental reagents on the cleaning andsample preservation. Finally, assembly of silver nanowires was carried out with assistance of THF(tetrahydrofuran).