Small molecules for interface engineering: tuning molecular transport characteristics and adhesion mechanisms

The general topic treated within this thesis is the synthesis of molecules for applications on surfaces for functional materials. But before the preparation and integration of molecular components into cutting edge devices, a fundamental understanding of the structure-property relationship of molecules is required. As a result, the structure-property relationship of several molecules associated with functional materials was investigated and can be categorised into two main topics. On one side, there is the interlinking of an organic structure and a bulk metal or metal oxide surface and on the other side, the electric and thermoelectric transport properties of organic structures anchored to gold electrodes. Although, not obvious at the first glance, both topics heavily rely on the way molecules are anchored to surfaces. Additionally, all treated subjects are accompanied by the beauty incorporated in the process of theorising and designing a specific structure, and then bringing it to reality. Therefore, a general introduction involving all of the investigated topics will be presented in the first chapter, followed by three individual chapters that describe the work performed within this PhD thesis. In the second chapter, the exploration of a novel silicon oxide functionalisation strategy utilising benzothiazole based structures will be elucidated. In the third chapter we will be looking at the transport properties of tolane-based structures, where the effect of different contacting modalities, internal conformation and electronic density variation of the backbone onto the transport properties of this very building block will be investigated. Thereafter, we will leave the family of closed-shell organic molecules and dive into the rich and interesting world of open-shell organic molecules (radicals) and their transport properties, which will be the topic of the fourth chapter. All experimental protocols and additional information supporting the research, presented in chapter two to four, are presented in the fifth and last chapter.