Advantage of arch-shaped structure on transistor performances over linear-shaped structure in dibenzothienopyrrole semiconductors

Abstract To understand the influence of molecular shape on the optoelectronic properties of heteroacenes, we report here the syntheses and characterizations of two linear- and two arch-shaped dibenzothienopyrrole ( DBTP ) derivatives, namely, N -hexyldibenzothieno[3,2- b :2′,3′- d ]pyrrole ( l -HDBTP) , N -phenyldibenzothieno[3,2- b :2′,3′- d ]pyrrole ( l -PDBTP) , N -hexyldibenzothieno[2,3- b :3′,2′- d ]pyrrole ( a -HDBTP) and N -phenyldibenzothieno[2,3- b :3′,2′- d ]pyrrole ( a -PDBTP) . Their structure-property relationships have been systematically studied by optical absorption, cyclic voltammetry, single-crystal X-ray diffraction analyses and the single-crystal-based and thin-film-based field-effect transistors (FETs). The results demonstrate that the arch-shaped DBTP derivatives can modify their electronic structures and molecular arrangements by tuning of substituents, to obtain a better charge-transporting ability relative to the linear-shaped ones. The arch-shaped N -phenyl substituted a -PDBTP exhibits optimum molecular π-stacking arrangement and charge transport properties, with the hole mobility of 0.75 cm 2 V −1 s −1 and 0.058 cm 2 V −1 s −1 for the single-crystal and the thin-film OFETs, respectively. These results indicate that the arch-shaped DBTP core is a promising building block in the area of organic semiconducting materials.