Emergence of mixing-induced polymorphic phase with higher mobility in alkylated layered organic semiconductors

The fabrication of functional layers with desired molecular ordering is a fundamental challenge in organic electronic materials. In this study, the authors demonstrate that the layered crystalline order of alkylated organic semiconductors can be precisely controlled by mixing molecules with varying alkyl chain lengths, resulting in a nearly tenfold enhancement in hole mobility compared to the parent materials. Advanced structural analysis using electron diffraction reveals that the crystal structure of the mixing-induced phase is stabilized by alkyl chain interdigitation between molecular layers. This discovery presents a novel approach to structural control that does not rely solely on the development of new organic semiconductor molecules.