Accessing New DPP-Based Copolymers by Direct Heteroarylation Polymerization

A diketopyrrolopyrrole derivative was copolymerized with different electron-withdrawing units [i.e., thieno[3,4-c]pyrrole-4,6-dione (TPD), bis(thieno[3,4-c]pyrrole-4,6-dione) (BTPD), and 3,4-dicyanothiophene (DCT)] using direct heteroarylation polymerization (DHAP) methodology. Alternating copolymers with low-lying frontier orbitals suitable for n-type semiconducting behavior were obtained. Under optimized conditions, polymerization reactions were reproducible and high number-average molecular weights (Mn) were achieved. Density functional theory (DFT) calculations indicated that the structures with the lowest conformational energy had planar backbones. Preliminary results showed that these new low-bandgap materials exhibit good n-type behavior.