Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 2: Colloide, Nanopartikel und Kapseln

CPP 2.8: Vortrag

Montag, 24. März 2003, 12:00–12:15, ZEU/260

Conductive Core-Shell Nanoparticles: An Approach to Self-Assembled Electrical Circuits — •Gisela Kaltenpoth^1,2, Michael Himmelhaus¹, Lorenz Slansky², Frank Caruso³, and Michael Grunze¹ — ¹Angewandte Physikalische Chemie, Universität Heidelberg, Germany — ²DaimlerChrysler Research and Technology, Germany — ³Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia

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.