Abstract

Most fascinating phenomena are observed in materials where various interactions take place on the same energy scale. Prominent examples thereof are organic-inorganic hybrid systems whose building blocks are very different in nature. Being governed by the interplay of electron-electron interaction, electron-phonon coupling, electron-hole correlations, and potentially also spin-orbit coupling, they pose challenges to the ab initio description of their electronic excitations. For example, density-functional theory has been found to predict the wrong level alignment at interfaces of organic molecules and 2D materials and therefore cannot be used as a starting point for describing optical and transport properties. Here, forefront many-body methodology is required to treat all interactions on the same footing. I will show the critical role of mutual dynamical screening of the constituents and how hybrid and charge transfer excitations can form at such interfaces. Another important example that I will present in this context, are 3D and 2D hybrid halide perovskites. In addition to discussing exciton physics in such complex materials, I will give an outlook towards exciton dynamics.