Surface Organization of Donor-Acceptor Polymers for Transistor Applications

The control of molecular organization in donor-acceptor polymers over various length scales is essential for the charge carrier migration in organic field-effect transistors. Comprehensive understanding of the relation between chemical structure of the polymer, molecular packing, self-assembly, microstructure and charge carrier transport after solution processing, has been carried out thoroughly. The impact of the molecular structure variation on the local packing of the polymer chains within well-defined layer-type superstructures has been found. The role of molecular weight, bulkiness, and substitution position of the alkyl chains and backbone curvature on the packing, microstructure and device performance is discussed. The surface organization of polymer and its film microstructure are also influenced by the processing conditions. Corresponding processing techniques have been developed that allow a fine control over the film deposition, microstructure formation and molecular orientation. Under optimized conditions, defect-free and highly ordered mesoscopic fibers result in superior device properties. The following minireview is separated into two main topics which cover the influence of chemical design and processing conditions on local packing and microstructure formation of polymeric organic semiconductors applied in field-effect transistors.