Nanometal conductive layers and organic heterostructures for polymer semiconductor devices

Abstract

The further development of organic polymer electronics depends on advances in printable materials systems and in multilayered semiconductor heterostructures. We modified the Brust-Schiffrin process by mixed functionalised carboxy- and hydroxyl-alkylthiol monolayers to produce extremely water dispersible nanoparticles. Their thin films can be annealed to the high conductivity state below 250 degrees C. This makes it possible to deposit these materials directly on organic underlayers without damaging them. The critical challenges of coalescence-induced cracking are overcome by forming nanocomposites with compatibilising polymer matrices. These materials are useful as electrodes in transistors and interconnects in light emitting diodes and photovoltaic cells. In the second part of this work we demonstrate that sequentially solution-deposited semiconducting polymer films can be doped to give p-i-n structures by contact with dopant solutions or dry dopant films. We demonstrate efficient p-i-n light emitting diodes based on p-doped, intrinsic and n-doped layers of poly (9, 9-dioctylfluorene-alt-benzothiadiazole).