Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 23: Plasmonics and Nanooptics: Structure, Fabrication and Characterization

O 23.9: Talk

Tuesday, March 17, 2015, 12:30–12:45, MA 043

Surfactant-Controlled Kinetic Overgrowth of Gold Rods into Gold-Core Silver-Shell Rodboids to Induce Controlled Internal Mirror Charges — •Tobias König, Moritz Tebbe, Martin Mayer, Christian Kuttner, and Andreas Fery — Physical Chemistry II, University of Bayreuth, 95447 Bayreuth, Germany

We present the surfactant-controlled overgrowth of gold nanorods into gold-core silver-shell nanoparticles (rodboids) to gain low growth rates for full control of the kinetic process. In gold-core silver-shell rodboids not much attentions has been paid to the overlap region of the intraband gaps of gold and silver (326 to 515 nm). In this optical region, the gold core acts as a retarding element because of the much higher damping in the core compared to the silver shell. Electromagnetic simulations show that the silver shell induces mirror charges at the core/shell interface which results in a similar signature as an anti-bonding mode. An excitation outside the overlap region yields in-phase oscillations of the surface charges (signature of a bonding mode). In contrast to plasmonic hybridization, the energetic splitting of the two modes is weaker so that both modes are present in the optical spectrum. Consequently, full control over the kinetic process allows for precise tailoring of the resonance wavelengths of both modes. Tailored rodboids represent ideal candidates as a building block for metamaterials and are suitable for application as optical sensor, light harvesting, and information technology.