In-silico experiments on the nanoscale

The emerging field of nanophysics offers innovative technologies, but meets also considerable public safety concerns. A detailed understanding of the processes that occur on the nanoscale are therefore crucial both to improve on existing technologies and to reduce reservations against these. In this talk we present theoretical methods that allow for the simulation of light- induced effects in nanomaterials from first principles at a moderate computational cost. After discussing the chances and challenges of these approaches, several case studies illustrate the level of information that can be drawn from such calculations: For Silicon nanocrystals, we discuss questions of quantum confinement, state localization and the effect of functionalization. Photo-darkening and light-induced defect formation are then investigated for some amorphous chalcogenides, and we close with preliminary results on low-cost photovoltaic cells that feature dye-coated TiO nanoparticles as functional ingredient.