Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.64: Poster
Wednesday, March 16, 2011, 17:30–21:00, P4
Volume plasmon modes in Ag@Au core-shell nanoparticles — Katja Höflich1, Aliaksei Dubavik2, Nikolei Gaponik2, Silke Christiansen1, Alexander Eychmüller2, Lukas M. Eng3, and •Thomas Härtling4 — 1Max-Plack-Institut für Mikrostrukturphysik, 06120 Halle, Germany — 2Physikalische Chemie und Elektrochemie, TU Dresden, 01062 Dresden, Germany — 3Institut für Angewandte Photophysik, TU Dresden, 01062 Dresden, Germany — 4Fraunhofer Institut für Zerstörungsfreie Prüfverfahren, 01109 Dresden, Germany
In the case of special nanoparticle geometries like e.g. spherical nanoshells and cylindrical core-shell structures, classical light can not only excite surface plasmons, but also volume plasmon modes [1, 2]. We investigate the properties of such a volume mode in core-shell Au@Ag nanoparticles which we find manifested as an UV extinction peak in the plasmonic spectrum. Analytical calculations with varied dielectric functions for the particle shell demonstrate that the mode occurs if the permittivity of the shell vanishes. We furthermore provide both theoretical and experimental proof that in contrast to surface plasmon modes the spectral position of the volume mode is independent of the core-shell geometry. To this end, we calculated and prepared Au@Ag particles with different geometries and compare their extinction spectra. [1] K. Höflich, U. Gösele, C. Christiansen, Phys. Rev. Lett. 103, 087404 (2009) [2] K. Höflich, U. Gösele, C. Christiansen, J. Chem. Phys. 131, 164704 (2009)