Electronic structure of organic interfaces - a case study on perylene derivatives

Organic semiconductors have attracted increasing interest owing to their potential application in various electronic and opto-electronic devices. Here, interfaces play an important role since they are responsible for the accumulation of charge carriers at and the efficiency of charge injection across interfaces. Both mechanisms are determined by the alignment of energy levels at the interface. This report is divided into two parts and presents some of the major physical mechanisms which determine the energy level alignment at interface of thin films of low molecular weight organic semiconductors. In the first part, the origin of interface dipoles, interface states, and surface band bending is discussed. In the second part, investigations on the properties of metal/perylene derivatives/inorganic semiconductor structures give further insight into the mechanisms at work, especially under non-thermal equilibrium conditions.