Regensburg 2007 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: POSTER: INTERNAL SYMPOSIUM Optical Spectrosopy

CPP 22.4: Poster

Wednesday, March 28, 2007, 16:00–18:30, Poster B

Mapping the Diffusional Landscape of a Porous Nanostructure — •Johanna Kirstein, Andreas Zürner, Steffen Schmidt, Markus Döblinger, Thomas Bein, and Christoph Bräuchle — Dept. Chemie und CeNS, LMU München, Germany

Single Molecule Spectroscopy (SMS) is used in combination with Transmission Electron Microscopy (TEM) to trace out the internal structure of mesoporous thin films and to gain insight into the diffusion dynamics with respect to the underlying structure of the host. Individual dye molecules acting as molecular beacons are incorporated into the pores and their diffusion pathway through the pore system is observed by optical widefield microscopy. However, structural features on the nanometer scale can not be observed by optical methods. To resolve the pore structure in detail TEM measurements are needed. Usually, the sample preparation for TEM is either time-consuming, when it involves the preparation of cross-sections, or it lifts the film off its substrate by scratching. With such methods it is thus not possible to directly correlate the nanopore structure of the film and the trajectories of the dye molecules obtained by SMS.

Here, we present the synthesis of thin mesoporous films loaded with fluorescent dye molecules that can be successively investigated by optical widefield microscopy and TEM. We developed a method to overlay the images obtained by the two methods. This is the first time that dynamical information from single particle diffusion can be directly correlated with the structural details of the porous host obtained by TEM.