Rapid formation and macroscopic self-assembly of liquid-crystalline, high-mobility, semiconducting Thienothiophene.

Abstract

A synergistic approach to enhance charge‐carrier transport in organic semiconductors along with facile solution processing and high performance is crucial for the advancement of organic electronics. The floating film transfer method (FTM) is used as a facile and cost‐effective method for the fabrication of large‐scale, uniform, highly oriented poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] (pBTTT C‐14) films under ambient conditions. Utilization of such oriented films as the active semiconducting layer in organic field‐effect transistors (OFETs) results in highly anisotropic charge‐carrier transport. Highly oriented, FTM‐processed pBTTT C‐14 thin films are characterized by polarized electronic absorption and Raman spectroscopy, atomic force microscopy, out‐of‐plane X‐ray diffraction, and grazing incident X‐ray diffraction (GIXD) measurements. The GIXD data indicate an edge‐on orientation, which is highly desirable for planar devices such as OFETs. OFETs built using the oriented films show a mobility anisotropy of 10 and the highest mobility is 1.24 cm2 V−1 s−1 along the backbone orientation, which is among the highest value reported for this class of materials using a similar device configuration.