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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Nanoparticles and Composite Materials II

CPP 27.1: Talk

Wednesday, March 13, 2013, 15:00–15:15, H39

Growth of silver nanowires within nanotubular J-Aggregates — •Egon Steeg, Holm Kirmse, Frank Polzer, Yan Qiao, Jürgen Rabe, and Stefan Kirstein — Institut für Physik, Humboldt-Universität zu Berlin

It was demonstrated earlier [1] that ultrathin but long Ag nanowires with diameters less than 7 nanometer and length exceeding micrometers can be fabricated by reduction of silver salt using uniform nanotubular J-Aggregates of amphiphilic cyanine dyes as templates. Here, we report on the growth mechanism of these Ag wires as revealed by conventional and cryogenic transmission electron microscopy. The growth is initiated by short illumination with UV light and observed over time scales ranging from minutes to days. In an early stage, within the tubular aggregates silver nanoparticles are formed which act as seeds for continous growth of separate pieces of wires. The diameter of the wires is determined by the inner diameter of the tubes. In the final state, the pieces of wire totally fill the aggregate. As revealed by high resolution TEM, the fragmented growth of the wires from separate seeds leads to silver nanowires consisting of single crystalline domains exceeding 100 nm in length. The growth process indicates transport of Ag-ions through the tubular wall membrane. The experiments demonstrate that these J-aggregates may also act as a soft template for the growth of other wire-like inorganic materials.

[1] D.M. Eisele et al., J. Am. Chem. Soc. 132 (2010) 2104.