Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.27: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
Laser-tailoring of the size and shape of gold nanoparticles in solution — •Florian Vogel, Frank Hubenthal, and Frank Träger — Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology – CINSaT, Universität Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
Tailoring of metal nanoparticles with laser light has been a well
known technique since several years. Although selective tailoring of
certain shapes or sizes of supported metal nanoparticles has been
demonstrated with ns-pulsed laser light, tailoring of nanoparticles
in solution has remained a challenge.
In this contribution, we
present recent studies on tailoring colloidal gold particles
prepared by wet chemical reduction of HAuCl4 with trisodium
citrate. In general, this method produces elongated particles with
relatively broad shape and size distributions. Post-synthesis
irradiation with ns-pulsed laser light with photon energies of 1.9
eV and a laser fluence of (52 ± 4) mJ/cm2 permits reshaping
to spherical particles. This is accompanied by a clear reduction of
the half width of the plasmon resonance, while the size of the
particles remains nearly constant at approximately R = 25 nm. In
contrast, if a photon energy of 1.4 eV and a comparable fluence is
used, particles with axial ratios of about 0.3 are selectively
heated and form colloids with radii up to 70 nm by coagulation.