Effect of random copolymerization on the optical properties of selenophene and thieno[3,4-c]pyrrole-4,6-dione conjugated polymers

• Four thieno[3,4-c]pyrrole-4,6-dione containing conjugated polymers were synthesized. • The effect of the introduction of selenophene as a π-spacer on optoelectronic properties is investigated. • The effect of random polymerization on optoelectronic properties is investigated. • The introduction of selenophene decreased the optical band gap. • The introduction of a second TPD unit increased the optical band gap. For the preparation of conjugated polymers having targeted band gaps, absorption, and optoelectronic properties, the Donor-Acceptor (D-A) approach has been one of the most convenient methods. We synthesized four new conjugated polymers, bearing selenophene and thieno[3,4-c]pyrrole-4,6-dione (TPD) for this study via Suzuki Stille Polycondensation. The effect of selenophene that was inserted as π-bridge and the introduction of a second TPD unit into the polymer backbones through random polymerization were investigated. Optoelectronic properties of the polymers were analyzed via electrochemical and spectroelectrochemical studies. The study reveals the effects of TPD and selenophene moieties on absorption and band gaps of the polymer and provides a concise approach for the preparation of D-A conjugated polymers.