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)-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 cm(2) V-1 s(-4), whereas the other two derivatives show orders of lower mobilities, which are in good agreement with our theoretical estimations.