Plasmonic metal nanoparticles (PMNPs), by virtue of their localized surface plasmon resonance (LSPR), are attractive for a range of applications centered in optics and sensing. Colloidally, PMNPs are largely limited to silver and gold nanoparticles. Silver is superior plasmonically and more amenable to shape-selective synthesis through oxidative etching, while gold features superior chemical stability – consequently, the composite Au-Ag PMNPs based on templating AgNPs can offer an optimal combination of functional properties. The surface chemistry of PMNPs is essential for their shape- and size-selective synthesis and transformations required for applications.<br/><br/>In the presentation, several topics based on our work with PMNPs will be reviewed from the perspective of nanoparticle surface chemistry: surface stability and species used in surface stabilization, modification and morphological control. First, synthesis of PMNPs will be considered in terms of two major pathways: thermal and photochemical, and their interplay with surface stabilization. Second, core-shell PMNP morphologies will be discussed, using an example of encapsulation of gold-plated silver PMNPs with metal oxide shells. The need for protective plating on AgPMNPs, the range of accessible metal oxides and conditions for uniform deposition with controlled shell thickness will be examined. Finally, surface plasmon resonance (SPR) sensing with PMNPs will be presented: sensing of surface-adsorbing species, the effect of morphological transformations, and approaches to impart sensing selectivity through the shell functionalities in core-shell PMNP morphologies.

Importance of surface chemistry in synthesis, transformations, and sensing applications of plasmonic metal nanoparticles

2019 Spring National Meeting

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