Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.16: Poster

Mittwoch, 25. März 2009, 17:45–20:30, P2

Optical spectroscopy of single laser-trapped gold nanoparticles — •Ninet Babajani, Stephan Eifel, Maximilian Reismann, and Gero von Plessen — Inst. of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany

The plasmon lines of chemically synthesized noble-metal nanoparticles of nearly spherical shape and approximately equal size exhibit surprisingly large particle-to-particle variations of their resonance peak positions and line widths [1].

The reasons for these spectral variations are still unknown. Possible explanations include faceting of the nominally spherical particles, charges and chemical effects within the suspension, and interactions with the substrate.

In this work, a method is presented in which a single gold nanoparticle suspended in an aqueous environment is trapped by an optical tweezer and its light-scattering spectrum, which is free of substrate effects, is measured. Subsequently the trapped nanoparticle is deposited onto a substrate using the optical tweezer and its spectrum is measured again. A comparison of the single-particle spectra allows us to draw conclusions about the origin of the spectral differences between the particles.

[1] C. Sönnichsen et al., New J. Phys. (2002) vol. 4 pp. 93