ABSTRACT
Recent advances in the performance of organic semiconductor materials in device configurations have been dramatic. In particular for light-emitting diodes (LEDs) [1-3], stability and durability have improved to levels that warrant their application in everyday life. The performance of organic optoelectronic devices has been found to depend crucially on the properties of the interfaces. This concerns electronic as well as structural aspects of interfaces. This feature can be exploited to improve the characteristics of a device. A well-known example is the incorporation of charge-transporting and charge-blocking layers in LEDs. Other functions of a layer between the active film and the electrodes may be to change the interface roughness or to act as a barrier for diffusion of oxygen or metal. In this chapter, the emphasis will be on the geometry of the interface between active components or, in other words, on the morphology of the active layer.
