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.