Molecular Self-Assembly of Methyl and Methoxy Substituted Benzoic Acids on Calcite(10.4) and Non-Equilibrium Structures of C60 on CaF2(111)

Research into nano materials is important for the future development of functional devices. Molecular self-assembly has been recognized as a promising tool in this endeavour, with insulating surfaces being particularly interesting for molecular electronics.<br /> Dynamic atomic force microscopy (AFM) in ultrahigh vacuum provides an excellent tool to study two dimensional self-assembled structures in a controlled environment. A precise understanding of the influence of the molecular structure on the self-assembly process is necessary in order to create specific structures on insulating surfaces. Unfortunately, it is not yet possible to predict the influence of small changes in the molecular structure on self-assembly. The structural variability is also lacking, due to self-assembled structures being confined to the thermodynamic equilibrium, and self-organised structures being inherently thermodynamically unstable.<br /> This thesis addresses both the influence of molecular structure on self assembly as well as the problem of structural variability.<br /> For the exploration of new molecular structures the existing knowledge of the self- assembly of benzoic acids on the calcite (10.4) surface is expanded by studying methoxy and methyl substituted benzoic acids on the same surface. Here, interesting new structures are found and unexpected changes to the intermolecular interactions are revealed.<br /> To create new structures for a given molecule-surface pairing, kinetically trapped non- equilibrium structures of C60 on the CaF2 surface are explored by variation of the preparation pathway. By comparing kinetic Monte Carlo simulations (kMC) with AFM experiments, the responsible molecular process could be identified.<br /> In summary, this thesis provides new insights into the molecular self-assembly on insulators, as well as a new avenue to increased structural variability on surfaces.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Bielefeld

Year

2024

Author dc:creator

• Höltkemeier, Lukas

Repository record source_url

https://pub.uni-bielefeld.de/record/3000619

OAI identifier oai:identifier

oai:pub.uni-bielefeld.de:3000619