Veranstaltungsdetails

6.7.2010, 17:00
Jungiusstr. 11, Hörsaal AP

SFB 668 - Kolloquium

Prof. Angelika Kühnle (Universität Mainz) :

Self-assembly of organic molecules on calcite

Molecular self-assembly represents a very promising strategy for surface functionalisation and fabrication of tailor-made functional structures e.g. for future molecular electronic devices. Consequently, molecular self-assembly has been studied extensively using scanning tunneling microscopy, gaining considerable insight into the mechanisms governing molecular self-assembly on metallic surfaces. For many applications, however, these studies need to be extended to insulating substrates in order to reduce electronic coupling to the substrate surface. So far, employing molecular self-assembly on insulating surfaces has been hampered by the comparatively high molecular mobility at room temperature. First attempts to create tailor-made molecular structures on insulating surfaces have resulted in clustering at step edges or even bulk crystal formation. Here, several approaches towards controlled molecular structure formation on insulating surfaces in ultra-high vacuum will be presented. Besides molecular structures formed on CaF2(111), emphasis will be on the natural cleavage plane of calcite. Calcite, being the most stable polymorph of CaCO3, plays a crucial role in a variety of different fields such as biomineralization and environmental geochemistry. Despite this, a controversy exists as to whether the (10-14) cleavage plane of calcite reconstructs or not. Self-assembly of different organic molecules on calcite will be presented, demonstrating the uni-directional growth of molecular wire-like structures on this insulating substrate. Promising aspects of on-surface covalent linking as well as high-resolution measurements under liquid conditions will be given in the outlook.