Controlled Synthesis of Silver Nanostructures Using Polyol Methods

Abstract

This dissertation presents results from a series of studies aims at developing methods to achieve better control of the synthesis of silver nanostructures using the polyol method. Silver nanostructures have attracted significant research interest in both academia and industry due to their wide range of applications and reasonable cost. The polyol method, in which the polyol solvent reduces silver salt precursor to metallic silver, has shown great potential as a controllable, low-cost, and large-scale means to synthesize various silver nanostructures. However, it is still a challenge to produce purposefully nanostructures such as nanowires and nanobars in a controlled manner with desired diameter, aspect ratio, and tight size distribution. One major knowledge gap is the lack of a thorough understanding of the reaction mechanism. A plausible hypothesis suggests that the morphology, size, and crystal structure of the silver nanoparticles (Ag NP) seeds, as well as the combination of growing conditions, largely influence the size and shape of the final product nanomaterials. The silver reduction rate, the Ag-seeds-to-precursor ratio, and the nature of the capping agent exert the most control over the size and size distribution of product materials formed. Therefore, the production, stability, and growth of Ag NP seeds are at the center of silver nanostructure synthesis, and Ag NP seed preparation and growth were studied separately to provide detailed insight on the reaction mechanism. The knowledge gained from this research will contribute to the optimization of silver nanostructure synthesis.