The influence of directed π–π interactions in solution on the thin film organic semiconductor device properties of small molecule polymer blends

Abstract

In good solvent 6,13-(triisopropylsilylethynyl) pentacene (TIPS-pentacene) was found to persist only as a unimer in solution at very low concentration, forming dimers and subsequently higher aggregates with increasing concentration well below the solubility limit. The extent of dimer and higher aggregate formation was found to be influenced by the addition of isotactic polystyrene through the formation of a supramolecular complex between TIPS-pentacene and isotactic polystyrene in a mutually good solvent through π–π stacking interaction. We believe this behaviour is a contributory factor in the previously reported improved organic thin film transistor device performance and stability of such blends mitigating the loss in performance often ascribed to solution processed small molecule organic semiconductors.