Controlling Two-Dimensional Molecular Assemblies and Emergence of Superlayer Cocrystals via Molecular Mixing

Rodlike organic molecules composed of a rigid π-conjugated core（π-core）and flexible alkyl chains tend to exhibit liquid crystalline（LC）phases which promotes the formation of quasi two-dimensional（2D）ordering in layered crystalline phases. Since the layered assemblies of π-cores typically afford efficient carrier transport in organic thin film transistors, the ability of rodlike molecules to form layered structures is particularly suitable for organic semiconductors（OSCs）. However, the method of controlling the quasi 2D structures of OSCs via LC states has not yet been developed. Here we demonstrate that the emergence of LC phase allows the formation of cocrystal phase composed of slightly different OSC molecules, which can be effective way of controlling a distinct cocrystal phase which cannot be realized by pristine compounds.