1,8-Substituted Pyrene Derivatives for High-Performance Organic Field-Effect Transistors

There have been many reports on the application of pyrene derivatives as organic semiconductors, but 1,8-subsituted pyrene semiconductors are less well-developed. Two p-type 1,8-substituted pyrene derivatives were synthesized that were composed of a pyrene core, thiophene or bithiophene arms, and end-capped octyl chains. These structures were not completely symmetrical and the dihedral angles between the pyrene core and the adjacent thiophene units had a difference of approximately two degrees. The field-effect performance of these materials was tested on a variety of dielectric surfaces. The performance of both materials with a spin-coated polystyrene layer on SiO₂ (PS-treated SiO₂) was better than that with an octadecyltrichlorosilane self-assembled monolayer on SiO₂ (OTS-treated SiO₂), which was mainly attributed to the presence of large grains on the low-leakage and high-capacitance PS films. The thiophene-contained compound presented a hole mobility of up to 0.18 cm² V⁻¹ s⁻¹ on PS-treated SiO₂, which was 45 times that of the bithiophene-contained compound, owing to less steric hindrance, high crystallinity, and large grain size.