Interaction of single metallo-porphyrins with Titania surfaces : advanced atomic force microscopy studies

In recent years, nanotechnology emerged as a new research field that has the goal to get control over matter at the nanoscale. Hence, basic research aims to understand and tailor the properties of the nanoscale building blocks such as single molecules or nanoparticles. The potential applications of such nanosystems comprise surface science, microfabrication, medicine and many more.
The present thesis examines this aspect for individual molecules that are adsorbed on surfaces. Thereby the surface gets functionalized with the molecular properties. The porphyrin-titania interfaces, which were studied in particular, become able to absorb light in the visible region. They are therefore suitable for application in organic-inorganic photovoltaics or photocatalysis. In order to enhance the performance of these interfaces it is important to investigate the molecular adsorption on the nanoscale. In this thesis, this task was first accomplished using a combined experimental approach with scanning probe microscopy (SPM) and photoelectron spectroscopy (PES) as well as density functional theory (DFT) calculations. The capability of atomic force microscopy (AFM) was further expanded during the thesis by the use of a recently developed measurement scheme. Applying this new method, it was demonstrated that the adsorption configurations of a single molecule at room temperature can be characterized by AFM alone. Hence, this thesis successfully pursued two main goals: the improvement of a well-known experimental technique and its use for high-resolution investigation of single molecules in application relevant organic-inorganic interfaces.