Architecting Layered Crystalline Organic Semiconductors Based on Unsymmetric π-Extended Thienoacenes

Herein, we demonstrate that engineered end-cap substitution for unsymmetric extended π-cores effectively achieves well-ordered two-dimensional (2D) molecular packing and thus realizes high-performance organic semiconductors (OSCs). We developed phenyl- and decyl-substituted benzothieno[6,5-b]benzothieno[3,2-b]thiophenes (BTBTTs) as solution-processable OSCs, providing layered single-crystalline thin-film transistors with a hole mobility of up to 12 cm2 V–1 s–1. The compound formed a bilayer-type layered herringbone packing in which the unsymmetric π-core aligned unidirectionally to form the respective molecular layers, owing to the well-balanced contributions of intermolecular interactions between the π-cores and between the respective end substituents. The eventual close intralayer molecular packing afforded a small effective mass and high thermal stability. These findings will be crucial for expanding the ability to develop high-performance OSCs.