Revealing the energy spectrum of plasmonic hot-carriers via single molecule transport measurements

Abstract

Direct experimental elucidation of steady-state energy distributions of hot-carriers in plasmonic nanostructures is key for systematically advancing and evaluating competing theoretical frameworks as well as for rationally engineering hot-carrier technologies. In this study, we present a novel scanning probe-based approach and show that quantum transport measurements from single molecule junctions, created by trapping suitably chosen single molecules between an ultra-thin gold film supporting surface plasmon polaritons and a scanning tunneling microscope probe tip, can enable quantification of plasmonic hot-carrier energy distributions. Several key physical insights on the nature of hot-carrier distributions, obtained from these measurements, will be discussed.