Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: POSTERS Dynamics and Diffusion
CPP 8.14: Poster
Montag, 25. Februar 2008, 16:45–19:00, Poster A
Adsorption Kinetics of Individual Dye Molecules on Semiconductor Nanocrystal Surfaces — •Mario Heidernätsch1, Thomas Blaudeck1,2, Jörg Schuster1, and Christian von Borczyskowski1 — 1Optical Spectroscopy and Molecular Physics, TU Chemnitz, 09107 Chemnitz, Germany — 2Print and Media Technology, TU Chemnitz, 09107 Chemnitz, Germany
Grafting of colloidal semiconductor quantum dots (QDs) with organic molecules is a common approach to adjust their optical, chemical, and electronic properties. In this respect, QD surfaces offer a certain yet finite number of binding sites to functionalization with molecules. With that, however, the common concepts of bimolecular reaction kinetics including their dissociation constants do not hold any more.
In our computational study, we employ numerical ab-initio techniques to separate the nanoaggregate formation process into the Brownian motion of an individual molecule in solution and its eventual adsorption and desorption in the potential of a particular binding site on the QD surface. Interestingly, the extrapolation of these elementary processes to an ensemble of QDs and molecules allows insights into the relationship between surface coverage and binding energies. Conclusions thereon are up to date impossible to draw solely by experimental methods. The comparison with previous results on the formation kinetics further backs the presence of a dynamic equilibrium.