Interfacial structure in semiconducting polymer devices

We discuss some recent findings relating to the structure of interfaces in semiconducting polymer devices. The structure of three different types of interface is characterized via neutron reflectivity and scanning force microscopy. In the first example we find that enrichment of dopant occurs at the surface of a doped polymeric conductor, and that this enriched layer penetrates several nanometres into the material. Secondly, we find that the interface between a semiconducting polymer and an insulating polymer is not molecularly sharp, but is rather broad with a width typically of the order of 1 nm. Finally we present some initial neutron reflectivity measurements on the interface between two different semiconducting polymers (one of which is deuterated). Again we find that this interface is diffuse, with a typical width of the order of a few nanometres.