title: Slow Relaxation of Surface Plasmon Excitations in Au55: The Key to Efficient Plasmonic Heating in Au/TiO2.
abstract: Gold nanoparticles distinguish themselves from other nanoparticles due to their unique surface plasmon resonance properties that can be exploited for a multiplicity of applications. The promise of plasmonic heating in systems of Au nanoparticles on transition metal oxide supports, for example, Au/TiO2, rests with the ability of the surface plasmon in Au nanoparticles to effectively transfer energy into the transition metal oxide. Here, we report a critical observation regarding Au nanoparticle (Au55) surface plasmon excitations, that is, the relaxation of the surface plasmon excitation is very slow, on the order of several picoseconds. Starting from five plasmon states in Au55 nanoparticles using nonadiabatic molecular dynamics simulations, we find that the relaxation time constant resulting from these simulations is ∼6.8 ps, mainly resulting from a long-lived intermediate state found at around -0.8 eV. This long-lived intermediate state aligns with the conduction band edge of TiO2, thereby facilitating energy transfer injection from the Au55 nanoparticle into the TiO2. The current results rule out the previously reported molecular-like relaxation dynamics for Au55.
authors.affiliation: Department of Physics and Astronomy, West Virginia University , Morgantown, West Virginia 26506-6315, United States.
authors.forename: Oshadha
authors.initials: O
authors.lastname: Ranasingha
authors.affiliation: Department of Physics and Astronomy, West Virginia University , Morgantown, West Virginia 26506-6315, United States.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnicḱa 10, CZ-16200 Prague, Czech Republic.|Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague , CZ-16200 Prague, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Zobač
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Cukrovarnicḱa 10, CZ-16200 Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jelínek
authors.affiliation: Department of Physics and Astronomy, West Virginia University , Morgantown, West Virginia 26506-6315, United States.
authors.forename: Gihan
authors.initials: G
authors.lastname: Panapitiya
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Neukirch
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.|Department of Chemistry, University of Southern California , Los Angeles, California 90089-1062, United States.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Prezhdo
authors.affiliation: Department of Physics and Astronomy, West Virginia University , Morgantown, West Virginia 26506-6315, United States.
authors.forename: James P
authors.initials: JP
authors.lastname: Lewis
mesh_terms: D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D006046:Gold; D014025:Titanium