Claudia Draxl, Humboldt-Universität, Berlin

From a theory point of view, the ab initio description of organic materials and, in particular, their interfaces to inorganic counterparts remains an exciting though challenging issue. Only having proper theoretical concepts and numerical tools in hand which consistently capture the features of molecular materials, from single molecules to hybrid interfaces, allows for getting insight into the leading excitation processes. As many-body effects play a dominant role forefront methodology, that is capable of reliably predicting the electronic structure and optical excitations, is a must.  Selected examples will show how many-body perturbation theory combined with density-functional theory can be used to explore, control, and predict level alignment and band gaps as well as light-matter interaction at hybrid interfaces, and how simple models and lower-level theory can fail.