title: From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties.
abstract: The optical properties of metallic nanoparticles are highly sensitive to interparticle distance, giving rise to dramatic but frequently irreversible color changes. By electrochemical modification of individual nanoparticles and nanoparticle pairs, we induced equally dramatic, yet reversible, changes in their optical properties. We achieved plasmon tuning by oxidation-reduction chemistry of Ag-AgCl shells on the surfaces of both individual and strongly coupled Au nanoparticle pairs, resulting in extreme but reversible changes in scattering line shape. We demonstrated reversible formation of the charge transfer plasmon mode by switching between capacitive and conductive electronic coupling mechanisms. Dynamic single-particle spectroelectrochemistry also gave an insight into the reaction kinetics and evolution of the charge transfer plasmon mode in an electrochemically tunable structure. Our study represents a highly useful approach to the precise tuning of the morphology of narrow interparticle gaps and will be of value for controlling and activating a range of properties such as extreme plasmon modulation, nanoscopic plasmon switching, and subnanometer tunable gap applications.
authors.affiliation: Smalley-Curl Institute Applied Physics Program, Rice University, Houston, TX 77005, USA. ; Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Chad P
authors.initials: CP
authors.lastname: Byers
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Dayne F
authors.identifier: 0000-0003-0274-4815
authors.initials: DF
authors.lastname: Swearer
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Yorulmaz
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Hoener
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Da
authors.initials: D
authors.lastname: Huang
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Anneli
authors.initials: A
authors.lastname: Hoggard
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA.
authors.forename: Wei-Shun
authors.initials: WS
authors.lastname: Chang
authors.affiliation: School of Chemistry and Bio21 Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Mulvaney
authors.affiliation: Department of Chemistry, Rice University, Houston, TX 77005, USA. ; Materials Science and Nanoengineering, Rice University, Houston, TX 77005, USA.
authors.forename: Emilie
authors.initials: E
authors.lastname: Ringe
authors.affiliation: Smalley-Curl Institute Applied Physics Program, Rice University, Houston, TX 77005, USA. ; Department of Chemistry, Rice University, Houston, TX 77005, USA. ; Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA. ; Materials Science and Nanoengineering, Rice University, Houston, TX 77005, USA. ; Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Halas
authors.affiliation: Smalley-Curl Institute Applied Physics Program, Rice University, Houston, TX 77005, USA. ; Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA. ; Materials Science and Nanoengineering, Rice University, Houston, TX 77005, USA. ; Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Peter
authors.identifier: 0000-0002-1633-2937
authors.initials: P
authors.lastname: Nordlander
authors.affiliation: Smalley-Curl Institute Applied Physics Program, Rice University, Houston, TX 77005, USA. ; Department of Chemistry, Rice University, Houston, TX 77005, USA. ; Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Stephan
authors.initials: S
authors.lastname: Link
authors.affiliation: Smalley-Curl Institute Applied Physics Program, Rice University, Houston, TX 77005, USA. ; Department of Chemistry, Rice University, Houston, TX 77005, USA. ; Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Christy F
authors.initials: CF
authors.lastname: Landes
keywords: Nanoparticles; active plasmonics; charge transfer plasmon; interparticle gaps; materials science; optical properties