(Invited) Photophysics and Photochemistry of Individual Plasmonic Nanostructures

Abstract

A surface plasmon in a metal nanoparticle is the coherent oscillation of the conduction band electrons leading to both absorption and scattering as well as strong local electromagnetic fields. These fundamental properties have been exploited in many different ways, including surface enhanced spectroscopy and sensing, photocatalysis, photothermal cancer therapy, and color display generation. Chemical synthesis and assembly of nanostructures are able to tailor plasmonic properties that are, however, typically broadened by ensemble averaging. Single particle spectroscopy together with correlated imaging is capable of removing heterogeneity in size, shape, and assembly geometry and furthermore allows one to separate absorption and scattering contributions. In this talk I will discuss our recent work on distinguishing the different contributions that cause plasmon decay as probed by the homogeneous single-particle linewidth.[1-4] In particular, I will focus on plasmon damping due to energy and charge transfer from the metal to its environment with the goal to mechanistically understand how energy conversion from an incident photon to a plasmon and then a localized excitation can be maximized while circumventing fast metal-intrinsic internal conversion that simply leads to heat generation.