Novel Thiophene–Phenylene–Thiophene Fused Bislactam-Based Donor–Acceptor Type Conjugate Polymers: Synthesis by Direct Arylation and Properties

Abstract

Three new donor–acceptor copolymers based on thiophene–phenylene–thiophene fused bislactam and various donors (3,4-dodecylthiophene, 4,4′-didodecyl-2,2′-bithiophene, and ethylenedioxythiophene) were synthesized, characterized, and used in field-effect transistors. Polycondensation was performed using nonactivated thiophene derivatives by employing palladium-catalyzed direct arylation under phosphine-free conditions. This method is superior to traditional cross-coupling polymerization because it requires fewer synthetic operations and does not employ toxic organometallic intermediates. Regioselective polymers can also be generated by using β-substituted thiophene derivatives. The studied polymers were tested in a bottom gate top contact thin film transistor (OTFT) architecture. The best electronic performance was shown by polymer P3, with enhanced π-conjugation due to the appearance of intramolecular attractive interactions.