The main focus of the ultrafast spectroscopy workgroup is on the investigation of photo-induced processes in both semiconductor nanostructures and molecular systems which are complexly structurally (functionally) correlated (e.g., in molecular semiconductor-hybrid materials or a cellular environment). The center of interest is systems with potential applications for the conversion of solar energy into usable forms of energy (e.g., in photocatalysis and photoelectrochemical catalysis for use in water splitting or Grätzel solar cells). In addition, systems with specific interactions with their environment are investigated regarding their usability, for example, as sensors or as photoactive therapeutics.
The goal is the development of a detailed understanding of such influential factors as the molecular structure, the type of coupling between molecules and semiconductors, and the morphology of semiconductor nanostructures on the photo-induced processes to be monitored, as well as an understanding of the relationship to the desired function.
Different optically spectroscopic methods are available for the investigation of photo-driven processes in molecules, molecularly-functionalized semiconductor surfaces, and semiconductor nanostructures. Time-resolved transient absorption spectroscopy and emission spectroscopy make it possible to trace photo-induced processes from the fs to the ms time scale. In addition, cavity ring-down spectroscopy, spectroelectrochemical methods, in situ and in operando spectroscopy, and microspectroscopic technology such as, for example, resonance Raman microscopy and transient absorption microscopy are also used. This workgroup addresses not only the application of these methods in connection with specific physical/chemical issues but strives to further develop these spectroscopic methods in terms of sensitivity and spatial and temporal resolution and to adapt them to deal with certain issues.