Fundamental prerequisites to understand the physics inside organic electronic devices and improve their performance are the reliable extraction of material parameters and to have a good device model to investigate the impact of the physical parameters on the device operation and performance. We characterize pip devices using steadystate and impedance techniques and determine parameters using using the driftdiffusion model implemented in SETFOS. To further improve our device model, the physics of organic/organic interfaces was investigated and a comprehensive model based on the hopping transport theory was derived. It is able to capture the mechanisms happening in charge generation or recombination units in tandem devices., Presenter: Beat Ruhstaller