(495c) Mechanism and Design Principles for Directing Energy Flow in Multicomponent Plasmonic Systems

Plasmonic metal nanoparticles exhibit enhanced light-matter interactions through the excitation of localized surface plasmon resonance. Plasmon excitation results in the confinement of light energy to the nanoparticle surface manifested in high electric field enhancements. This elevated field subsequently decays through either radiative photon scattering or through non-radiative excitation of hot carriers in the bulk material. Many researchers have been attempting to understand the mechanisms of plasmon decay in metallic nanoparticles with the ultimate objective of controlling this decay process.

In this presentation, we shed light on the physical mechanisms underlying plasmon decay in multicomponent plasmonic systems. Using Raman spectroscopy, we show that the introduction of a probe molecule on the surface of plasmonic nanoparticles introduces a new plasmon decay pathway resulting in the selective dissipation of light energy into the molecule. We develop the physical framework governing this energy dissipation and discuss our application of this framework to the design of multimetallic plasmonic nanostructures. We demonstrate that by coating plasmonic nanoparticles with non-plasmonic metals, the plasmon energy is selectively dissipated in the non-plasmonic metal shell. We provide insights into how this physical framework can aid the rational design of multicomponent plasmonic systems for various applications in light harvesting, plasmonics and photocatalysis.