Inducing Molecular Aggregation of Polymer Semiconductors in a Secondary Insulating Polymer Matrix to Enhance Charge Transport

Polymer semiconductors (PSCs) are a desirable class of materials for next-generation electronics. However, the conformational complexity associated with macromolecules, as well the presence of unique inter- and intra-chain interactions, make it challenging to control the morphology of PSCs. Previously, it has been reported that beyond a certain molecular weight, thin film charge carrier mobility typically drops due to reduced crystallinity and increased entanglement. Here, the use of an insulating secondary matrix polymer, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS), is shown to induce molecular ordering of PSCs across multiple length scales. Aggregation-induced molecular ordering in SEBS/PSC hybrid films is strongly correlated to the molecular weight of the semiconducting component. The higher the molecular weight of PSC used to blend with SEBS, the greater the observed improvement in polymer aggregation and orientation. This leads to a 5-fold increase of charge carrier mobilit...