Acenaphtho[1,2-b]quinoxaline based low band gap copolymers for organic thin film transistor applications

Abstract

We report the synthesis of a novel class of low band gap copolymers based on an acenaphtho[1,2-b]quinoxaline core and oligothiophene derivatives acting as the acceptor and the donor moieties, respectively. The optical properties of the copolymers were characterized by ultraviolet-visible spectroscopy while the electrochemical properties were determined by cyclic voltammetry. The band gap of these polymers was found to be in the range 1.8–2.0 eV as calculated from the optical absorption band edge. X-ray diffraction measurements show weak π–π stacking interactions between the polymer chains. The hole mobility of the copolymers was evaluated using field-effect transistor measurements yielding values in the range 10−5–10−3 cm2/Vs.