Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Poster: Interfaces and Thin Films

CPP 13.18: Poster

Dienstag, 27. März 2012, 18:15–20:45, Poster A

Functionalization of silicon oxide nanopatterns by selective binding of fluorescent molecules — •Thomas Baumgärtel¹, Christian von Borczyskowski¹, and Harald Graaf² — ¹Center of Nanostructured Materials and Analytics, Institut für Physik, TU Chemnitz, 09107 Chemnitz, Germany — ²FB 10, Institut für Chemie, Heinrich-Plett-Str. 40, 34132 Kassel, Germany

Local anodic oxidation (LAO) of alkyl-terminated silicon is a neat way for generating nanostructures with lateral dimensions below 100 nm and a height of a few nm. One of the remaining challenges is to give those structures a desired functionality in order to build more complex systems. Functionalization can be achieved via different methods such as electrostatic or covalent binding of optically active materials (e.g. molecules or nanoparticles). Here we report on the selective binding of dye molecules to LAO nanostructures and their investigation by means of temporally and spectrally resolved fluorescence microscopy. The spectra of bound perylene dyes have only little similarity to the monomer spectrum, are strongly red-shifted and the radiative transition is characterized by a higher lifetime of the excited state. This can be understood in terms of an oligomer formation of the dyes bound to the nanostructure similar to thin films or stacks of perylene derivatives. Fluorescein dyes that are bound covalently to the oxide on the other hand exhibit a spectrum which is quite similar to the monomer spectrum except of a slight red-shift caused by the different environment. Both systems may be promising candidates for chemically well-defined optically functional nanodevices on semiconductor surfaces.