Study On The Synthesis And Optical Properties Of Silver Nanostructure

Due to small size effect, quantum size effect, surface effect and quantum tunnel effect,nanomaterials have fascinating properties which are different from corresponding bulk materials, thusnanomaterials have great potential foreground in many scientific fields. Noble metal nanomaterialswith unique chemical and physical properties have extensive applications in electronics, optics, sensorand biomedical. Their properties are directly bound up with the shape and size of metal nanoparticles.Therefore, it is believed that property-controllable metal nanoparticles will be conveniently producedby tuning their morphologies, sizes, dimensionalities and compositions and expected to be fabricatedinto functional nanodevices. So far, although there have been a great progress on the synthesis ofnanomaterials, the shape-controllable synthesis is still a challenge. Therefore, it is important to get theshape-controlled nanomaterials and design the functional nanodevices.Taking silver nanoparticles as the research object, in this dissertation, we firstly prepare silvernanoplates through light induction method; the growth mechanism was also studied. This dissertationalso prepare silver dendrites using sonochemical method; the growth mechanism was also speculated.The main results and conclusions of this dissertation are outlined as follows:1. We begin with a brief introduction to synthesis methods, including template method,seed-mediated method, photo-induced synthesis and sonochemical method, in which photo-inducedsynthesis and sonochemical method are taken in our experiment to prepare silver nanostructure.2. Synthesis plate-like silver nanoparticles. Silver nanoplates with stacking fault weresynthesized by photo-induced method. In this protocol, trisodium citrate served as both reductant andcapping agent to reducing AgNO3in the presence of light source. The microstructure of nanoplateswas studied by TEM, SAED and XRD measurements. On the basis of analyzing chemical reactionsand growth process, a growth mechanism was proposed.3. Synthesis dendrite-like silver nanoparticles. Nanostructured silver dendrites were synthesizedby using sonochemical method from an aqueous solution of [Ag(NH3)2]+in the presence ofPoly-vinylpyrrolidone (PVP) as surfactant and ethylene glycol (EG) as both reductant and solvent.The microstructure of silver dendrites was studied by TEM, UV-visible absorption spectrum. Thegrowth mechanism was also surmised.