Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 43: Nanomaterials

MM 43.2: Talk

Wednesday, March 14, 2018, 17:15–17:30, H 0106

Ideal Dimers of Gold Nanospheres for Precision Plasmonics: Experiment and Theory — •Jun Hee Yoon, Florian Selbach, Ludmilla Langolf, and Sebastian Schlücker — Department of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany

A dimer of two noble metal nanoparticles is the simplest system in which electronic coupling between the particles via plasmon hybridization occurs. Theoretical predictions are typically based on ideal dimers comprising two perfectly spherical particles. Here, we present the synthesis and characterization of single ideal dimers of spherical gold nanoparticles with control over both gap distance and gap morphology. Electron microscopic and optical microspectroscopic experiments at the single-particle level show an excellent structural uniformity and an unprecedented homogeneity of their optical scattering spectra. In contrast, non-ideal dimers, i.e., dimers of non-spherical/nanocrystalline particles, with the same gap distance exhibit highly non-uniform properties. Interestingly, non-ideal dimers generate blue-shifted longitudinal plasmon peaks compared with the ideal dimers. We therefore performed FDTD calculations on non-ideal dimers with different gap morphologies using icosahedral particles. The calculations clearly demonstrate that plasmonic coupling in non-ideal dimers strongly depends on the gap morphology, i.e., the orientation of the crystal facets of the particles in the gap.