Synthesis and studies on 2-hexylbithiophene end-capped oligomer for OTFT

Abstract

The new organic semiconductor which is composed of divinylbenzene core unit and hexylbithiophene on both sides, 1,4-bis-(1'-(2 ''-hexyl-5 ''-[2,2']bithienyl)ethenyl) benzene, was synthesized by Wittig reaction. The structure of obtained material was confirmed by NMR, FT-IR and mass, and the physical properties were characterized by UV-visible spectroscopy, cyclovoltammetry, differential scanning calorimetry, and thermogravimetric analysis. Vacuum-evaporated film was characterized by X-ray diffraction and atomic force microscopy (AFM). It forms highly ordered polycrystalline vacuum-evaporated film. It exhibits field-effect performances, with a hole mobility of 0.066 cm(2)/V and on/off ratio up to 4.61 x 10(5), and a subthreshold slope of 0.44 V when it was deposited at T-s = 90 degrees C on OTS-treated SiO2. (C) 2010 Elsevier B.V. All rights reserved.