An easily made thienoacene comprising seven fused rings for ambient-stable organic thin film transistors

A novel easily made thienoacene-based organic semiconductor, i.e., dinaphtho[3,4-d:3',4'-d']benzo[1,2-b:4,5-b']dithiophene (Ph5T2), was synthesized in high yield, and its thermal stability, electrochemical properties, thin-film morphology and field-effect mobility were investigated. Ph5T2 exhibit excellent thermal stability with a decomposition temperature (T-d) of 427 degrees C. Thin-film X-ray diffraction (XRD) and atomic force microscopy (AFM) characterizations indicate that Ph5T2 can form highly ordered films with large domain size on the para-sexiphenyl (6P)-modified substrates. Organic thin-film transistors (OTFTs) with top-contact geometry based on Ph5T2 exhibit mobilities up to 1.2 cm(2) V-1 s(-1) in ambient. The devices are highly stable and exhibit almost no performance degradation during 3 months storage under ambient conditions with relative humidity up to 80%. (C) 2012 Elsevier B.V. All rights reserved.