Zigzag-Elongated Fused π-Electronic Core: A Molecular Design Strategy to Maximize Charge-Carrier Mobility

Printed and flexible electronics requires solution-processable organic semiconductors with a carrier mobility (μ) of ≈10 cm² V^-1 s^-1 as well as high chemical and thermal durability. In this study, chryseno[2,1-b:8,7-b']dithiophene (ChDT) and its derivatives, which have a zigzag-elongated fused π-electronic core (π-core) and a peculiar highest occupied molecular orbital (HOMO) configuration, are reported as materials with conceptually new semiconducting π-cores. ChDT and its derivatives are prepared by a versatile synthetic procedure. A comprehensive investigation reveals that the ChDT π-core exhibits increasing structural stability in the bulk crystal phase, and that it is unaffected by a variation of the transfer integral, induced by the perpetual molecular motion of organic materials owing to the combination of its molecular shape and its particular HOMO configuration. Notably, ChDT derivatives exhibit excellent chemical and thermal stability, high charge-carrier mobility under ambient conditions (μ ≤ 10 cm² V^-1 s^-1), and a crystal phase that is highly stable, even at temperatures above 250 °C.