The combination of modern approaches of condensed matter theory or quantum chemistry with real materials to generate insights and knowledge is the main motivation for our work. The research in my group is focused on the development of first-principles-based methods to study the fundamental properties of new materials that are not well understood. Various computational tools and algorithms are used or developed in-house.
Optical Properties and Excitons
Excitonic effects are important in absorption spectra of most materials ranging from single molecules to bulk semiconductors. They also govern the physical mechanisms of solar cells based on organic materials. Here excitons may be interconverted between different species and specifically the charge-transfer excitons at interfaces play an important role for the working principle of solar cells. Their strong Coulomb binding makes them interesting objects to study and the coupling to the molecular vibrations adds additional degrees of freedom that we investigate in this research line.
Organic Semiconductors and Covalent Organic Frameworks
These classes are based on molecules in condensed phases. They offer great potential as the molecular structure is precisely defined. Changing a single atom may change the physical properties completely. Electronics based on molecular structures is therefore an obvious direction for science because of the unique ways to manipulate electronic properties by chemical means and other modifications. We investigate the process of doping and its connection to charge transport properties. In addition band structure engineering as well as thermoelectric properties are explored. Our research on electronic, optical and transport properties enjoys several fruitful collaborations.
Quantum Dynamics and Quantum Transport
Dynamical processes in materials like electron transfer, charge-carrier transport, polaron transport, and spin phenomena are main research directions in the group. This includes also phenomena like the Hall effect. The quantum-to-classical transition is of particular interest. Intriguing questions include: What is the role of coherence? What is the role of vibrations?