Effect of Electronically Distinct Aromatic Substituents on the Molecular Assembly and Hole Transport of V‑Shaped Organic Semiconductors

Bent-shaped p-type organic semiconductors (OSCs) have demonstrated high hole-carrier mobilities and thermal durability for practical electronic applications, among which, the V-shaped thieno­[3,2-f:4,5-f’]­bis­[1]­benzothiophene (TBBT–V) π-electron core shows excellent electronic features for hole transports, and the fused terminal thiophene units allow facile substitution with various substituents for fine-tuning OSC properties. Herein, we investigate the effect of TBBT–V functionalized with three electronically distinct aromatic substituents (phenyl, thienyl, and thiazolyl) on their molecular assemblies and charge-transporting capabilities. The phenyl-substituted TBBT–V (Ph–TBBT–V) forms the herringbone packing motif, with effective calculated intermolecular orbital overlaps and two-dimensional-like charge transport. On the other hand, poor charge-transporting capabilities are estimated for thienyl- and thiazolyl-substituted TBBT–V. As a result, Ph–TBBT–V, with the best estimated charge-transporting capability, exhibits an excellent air-stable hole mobility up to 6.5 cm2 V–1 s–1, whereas the other two derivatives show orders of lower mobilities, which are in good agreement with our theoretical estimations.