Metallic nanoparticles have found applications for thousands of years, starting with their use in stained glasses. We now know that the intense colors are due surface plasmons, the coherent oscillations of the conduction band electrons leading to intense absorption and scattering. Since then, surface plasmons have been exploited in many different ways, including recent efforts to generate hot carriers from plasmon decay and drive chemical reactions. Unlike in semiconductor photocatalysts, hot electrons and holes are, however, short-lived, leading to low overall quantum yields. Low efficiencies can be offset by large absorption cross sections and tunable resonances to match molecular orbital energies. However, to further enhance plasmonic photocatalysts an improved understanding of the generation and relaxation of hot carriers in different plasmonic nanostructures as a function of their surface chemistry is still necessary. In this talk I will discuss our recent work on plasmon generated hot carriers in gold and aluminum nanostructures. We employed single-particle spectroscopy to eliminate signal averaging over a heterogeneous distribution of nanoparticles and were able to quantify a variety of fundamental processes: interfacial energy and charge transfer(1), radiative emission(2), electron-phonon coupling(3), and localized nanoscale heating.
Speaker: Stephan Link, Rice University
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Stanford, CA 94305
Website: Click to Visit