Microwave assisted synthesis of bithiophene based donor-acceptor-donor oligomers and their optoelectronic performances

In this article we present the synthesis of two novel bithiophene based symmetrical π conjugated oligomers with donor-acceptor-donor (D-A-D) structures by microwave assisted PdCl₂(dppf) catalyzed Suzuki coupling reaction. These molecules contain electron rich bithiophene as a donor, dithienothiadiazole[3,4-c]pyridine and phthalic anhydride units as acceptors. The shorter reaction time, excellent yields and easy product isolation are the advantages of this method. The photophysical prerequisites for electronic application such as strong and broad optical absorption, thermal stability, and compatible energy levels were determined for synthesized oligomers. Optical band gap for the oligomers is found to be 1.72–1.90 eV. The results demonstrated the novel oligomers to be promising candidates in organic optoelectronic applications.