title: Molecular Plasmonics.
abstract: Graphene supports surface plasmons that have been observed to be both electrically and geometrically tunable in the mid- to far-infrared spectral regions. In particular, it has been demonstrated that graphene plasmons can be tuned across a wide spectral range spanning from the mid-infrared to the terahertz. The identification of a general class of plasmonic excitations in systems containing only a few dozen atoms permits us to extend this versatility into the visible and ultraviolet. As appealing as this extension might be for active nanoscale manipulation of visible light, its realization constitutes a formidable technical challenge. We experimentally demonstrate the existence of molecular plasmon resonances in the visible for ionized polycyclic aromatic hydrocarbons (PAHs), which we reversibly switch by adding, then removing, a single electron from the molecule. The charged PAHs display intense absorption in the visible regime with electrical and geometrical tunability analogous to the plasmonic resonances of much larger nanographene systems. Finally, we also use the switchable molecular plasmon in anthracene to demonstrate a proof-of-concept low-voltage electrochromic device.
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Adam
authors.initials: A
authors.lastname: Lauchner
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Schlather
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Manjavacas
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Yao
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McClain
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Stec
authors.affiliation: ICFO-Institut de Ciencies Fotoniques , Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.|ICREA-Institució Catalana de Recerca i Estudis Avancats, Passeig Lluís Companys , 23, 08010 Barcelona, Spain.
authors.forename: F Javier
authors.initials: FJ
authors.lastname: García de Abajo
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Nordlander
authors.affiliation: Laboratory for Nanophotonics, Smalley-Curl Institute, Rice University Houston, Texas 77005, United States.
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Halas
keywords: Plasmonics; electrochemistry; graphene; photonics; polyacenes; polycyclic aromatic hydrocarbons