AVS 50th International Symposium
    Contacts to Organic Materials Topical Conference Tuesday Sessions
       Session OM-TuP

Paper OM-TuP4
Conductive Core-Shell Nanoparticles: An Approach to Self-Assembled Mesoscopic Wires

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: G. Kaltenpoth, Universität Heidelberg, Germany
Authors: G. Kaltenpoth, Universität Heidelberg, Germany
M. Himmelhaus, Universität Heidelberg, Germany
L. Slansky, Daimler-Chrysler AG, Germany
F. Caruso, University of Melbourne, Australia
M. Grunze, Universität Heidelberg, Germany
Correspondent: Click to Email
Conductive core-shell nanoparticles were prepared by coating negatively charged monodisperse polystyrene (PS) latex spheres with a thin layer of polyethyleneimine (PEI). Subsequently, gold colloid with 3 nm in size was electrostatically adsorbed onto the PEI-coated spheres, and finally, an electroless gold plating step was repeatedly carried out to yield a high gold coverage and thus a conductive gold shell. The metallic behavior was investigated by XPS and UV-vis. In the XPS Au4f peak, a shift due to charging effects was observed at low metal coverage, which decreased with increasing gold decoration, and vanished with the formation of a conductive metal shell. The UV-vis spectra show a coverage-dependent shift and broadening of the Au plasmon resonance. The self-assembly of the metal coated spheres into continuous lines was investigated to explore the applicability of such particles to realize self-assembled electrical circuits. It was found that the particles selectively adsorb to the carboxyl-terminated areas of line patterns fabricated by microcontact printing of alternating carboxyl- and methyl terminated alkanethiolates on gold.