High Performance OTFTs Fabricated Using a Calamitic Liquid Crystalline Material of 2-(4-Dodecyl phenyl)[1]benzothieno[3,2-b][1]benzothiophene

An air-stable calamitic liquid crystalline material, 2-(4-dodecyl phenyl)[1]benzothieno[3,2-b]benzothiophene (C12-Ph-BTBT), is designed with a highly ordered smectic X (SmX) (X = K or H) phase demonstrating high charge-carrier mobility and thermal stability in thin-film transistors. Organic thin-film transistors show mobilities as high as 8.7 cm(2) V-1 s(-1) when the C12-Ph-BTBT thin film is annealed at its SmX phase before the electrode deposition. Structural characterization reveals that the as-deposited C12-Ph-BTBT thin films adopt a unilamellar structure. On the other hand, after polycrystalline thin films of C12-Ph-BTBT exhibit bilayer structure after annealing at the temperature of the SmX and the smectic E phases. The highest charge-carrier mobility is observed when the C12-Ph-BTBT thin films are annealed at the SmX phase before the electrode deposition. The results give insight into the understanding of the nature of the mesophase behavior of liquid-crystalline semiconductors and can aid the rational design of self-organizing molecular semiconductors.Shenzhen Science and Technology Research Grant [ZDSYS20140509094114164]; Nanshan Innovation Agency Grant [KC2015ZDYF0016A]; Guangdong Key Research Project [2014B090914003, 2015B090914002]; Guangdong Talents Project, NSFC [51373075]; National Basic Research Program of China (973 Program) [2015CB856500]; Guangdong Academician Workstation [2013B090400016]; Natural Science Foundation of Guangdong Province [2014A030313800]; China Postdoctoral Science Foundation [2015M570892]; National Science Foundation; National Institutes of Health/National Institute of General Medical Sciences under NSF [DMR-1332208]SCI(E)ARTICLEogoto@pkusz.edu.cn; lloo@princeton.edu; menghong@pkusz.edu.cn9