Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Electronic+Optical Properties
CPP 6.9: Vortrag
Montag, 25. Februar 2008, 16:15–16:30, C 230
Spectroscopic and Electrochemical Investigation of Tubular J-Aggregates During Photo-Assisted Growth of Silver — •Dörthe M Eisele1, Constans Weber1, Jennifer Lyon3, Hans v. Berlepsch2, Stefan Kirstein1, Christoph Böttcher2, Keith J Stevenson3, David A Vanden Bout3, and Jürgen P Rabe1 — 1Humboldt University Berlin — 2Free Universtiy Berlin — 3University of Texas at Austin
Cyanine dye J-aggregates have been intensively investigated as sensitizers for photo induced electron transfer processes and are used in photographic films to form elementary silver specks in solid silver halide crystallites. Of particular interest are tubular J-aggregates formed by amphiphilic cyanine dye molecules upon self assembly aggregation in aqueous solution. A detailed understanding of their physicochemical properties is necessary for applications as spectral sensitizers in artificial light harvesting systems.
In this contribution, this light accelerated electron transfer from the tubular aggregates to noble metal ions such as silver is studied. This photo assisted charge transfer induces the growth of metallic nanoparticles that are located on the J-aggregate surface and does not disrupt the long-range tubular morphology. The reduction of the silver is observed by monitoring the oxidation of the J-aggregate using absorption and emission spectroscopy. Independent spectro-electrochemical investigations also show that the reduction of silver is associated with an oxidation of the cyanine dyes.