title: Resonances of nanoparticles with poor plasmonic metal tips.
abstract: The catalytic and optical properties of metal nanoparticles can be combined to create platforms for light-driven chemical energy storage and enhanced in-situ reaction monitoring. However, the heavily damped plasmon resonances of many catalytically active metals (e.g. Pt, Pd) prevent this dual functionality in pure nanostructures. The addition of catalytic metals at the surface of efficient plasmonic particles thus presents a unique opportunity if the resonances can be conserved after coating. Here, nanometer resolution electron-based techniques (electron energy loss, cathodoluminescence, and energy dispersive X-ray spectroscopy) are used to show that Au particles incorporating a catalytically active but heavily damped metal, Pd, sustain multiple size-dependent localized surface plasmon resonances (LSPRs) that are narrow and strongly localized at the Pd-rich tips. The resonances also couple with a dielectric substrate and other nanoparticles, establishing that the full range of plasmonic behavior is observed in these multifunctional nanostructures despite the presence of Pd.
authors.affiliation: Department of Materials Science and NanoEngineering, Rice University, 6100 Main St., Houston TX 77005, USA.
authors.forename: Emilie
authors.initials: E
authors.lastname: Ringe
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: DeSantis
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Collins
authors.affiliation: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institut 5 (PGI-5), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
authors.forename: Martial
authors.initials: M
authors.lastname: Duchamp
authors.affiliation: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institut 5 (PGI-5), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
authors.forename: Rafal E
authors.initials: RE
authors.lastname: Dunin-Borkowski
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405, USA.
authors.forename: Sara E
authors.initials: SE
authors.lastname: Skrabalak
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Midgley