ABSTRACT
The integration of several classes of materials, both organic and inorganic, as semiconductors, metals, or insulators in electronic devices requires many steps of harmonization to enhance performance. On the structural level, inorganic-inorganic interfaces may require minimal lattice mismatch in the joining of two semiconductor layers in order to prevent unwanted electronic effects. With disordered organic semiconductors and metals, such levels of refinement are rarely to be expected, but a number of useful examples are already there. The use of intermediate layers can be helpful for modifying injection and collection properties by changing energy barriers, by giving a rough surface an extra planarizing overcoat, or by acting as a diffusion barrier for species traversing the interface between two electronic conductors. There are many instances in which such interlayers are helpful in the context of polymer electronics. The first example within polymer electronics was found in the use of poly aniline as an injection-controlling layer inbetween the electroluminescent polymer and the transparent indium-tin-oxide (ITO) normally used in polymer light-emitting diodes (LEDs) [1,2]. Much before this, a decade back in time, polypyrrole in its metallic form was used to stabilize and electrocatalyze the photoelectrochemical interfaces between silicon and liquid electrolytes [3]. This effect was due to suppression of the photo-oxidation of silicon, which very rapidly would be limiting the photocurrent transport through devices.
