Design and synthesis of new donor-acceptor type conjugated copolymers derived from thiophenes

A new series of donor-acceptor type poly(thiophene) derivatives (P1-P3) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. In the final step, the polymerization was carried out using Wittig reaction. This is a good synthetic route for the preparation of any desired p- and n-type copolymers. The optical and potential charge-transporting properties of the copolymers were investigated by UV-vis, fluorescence emission spectroscopy and cyclic voltammetry. The copolymers exhibited bluish-green/green fluorescence in their thin film forms. Cyclic voltammetry experiments showed that these copolymers have low-lying LUMO energy levels ranging from −2.98 to −3.11 eV and high lying HOMO energy levels ranging from −5.45 to −5.65 eV. The optical and electrochemical studies reveal that new copolymers are new promising materials for the development of efficient polymer light emitting diodes.