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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Nanoparticles II

CPP 9.5: Vortrag

Montag, 23. März 2009, 15:00–15:15, ZEU 114

FRET and Non-FRET processes in quantum dot - dye nanoassemblies — •Danny Kowerko, Jörg Schuster, and Christian von Borczyskowsi — Center of nanostructured materials and analytics, TU-Chemnitz, 09107 Chemnitz

Assemblies of semiconductor quantum dots (QDs - donor) and organic (dye - acceptor) molecules are of increasing interest for numerous applications in science and technology. Recent publications on such systems report on charge and fluorescence resonant energy transfer (FRET), prevalently neglecting an exact quantitative spectroscopic analysis of the acceptor. Recently, calculations of Seifert et al. [1] and Blaudeck and coworkers [2] demonstrated the crucial dependence of trap state emission from the surface coverage. In our contribution we emphasize the role of dye induces surface trap states as one mechanism - besides FRET - for QD quenching. Thus detailed quantitative analysis of titration experiments of differently functionalized perylenebismide molecules and CdSe/ZnS quantum dots will be discussed. By means of single particle spectroscopy we may even compare spectroscopic properties of the free and bound species on one and the same sample under identical conditions. Furthermore, analysis of FRET allows for a distinction between different geometries of the dye-QD assemblies.

[1] J. Frenzel, J.-O. Joswig, G. Seifert, J.Phys.Chem.C 2007, 111, 10761 [2] T. Blaudeck, E. I. Zenkevich, F. Cichos, C. von Borczyskowski, J.Phys.Chem.C 2008, accepted