Gold nanocages and related nanostructures for plasmonic and biomedical applications

Abstract

Gold nanocages and related nanostructures have shown great potential in applications ranging from catalysis to theranostics. To make full use of these nanomaterials, it is crucial for us to precisely control their size, shape, and structure, since their physiochemical properties are determined by these parameters. This dissertation is focused on the synthesis of Au nanocages and their derivatives for photonic and biomedical applications. I start with the synthesis of Cu-doped Au nanocages through the co-reduction of Au and Cu precursors in the presence of pre-synthesized Au nanocages, and then demonstrate their use as a PET tracer when 64Cu is involved. With the insights gained from this study, I carry out a systematic study to examine the deposition of Pd on Au nanocages, and reveal the relationship between the reduction kinetics of metal precursors and the deposition behaviors. In the third project, I demonstrate the synthesis of compact Au nanorattles with edge length as small as 15 nm, through a two-step procedure that combines the deposition of Au on Ag nanocubes to enhance their physical robustness and a galvanic reaction to complete the synthesis. Finally, I demonstrate the synthesis of Ag@Au core-sheath nanowires through the deposition of Au on Ag nanowires in a galvanic-free manner, in an effort to improve their stability against various oxidants. The mechanistic understanding achieved in this dissertation paves the road for the rational design and controlled synthesis of colloidal noble-metal nanomaterials with desired sizes, shapes, compositions, and structures.