Effect of mono alkoxy-carboxylate-functionalized benzothiadiazolebased donor polymers for non-fullerene solar cells = Effect of mono alkoxy-carboxylate-functionalized benzothiadiazolebased donor polymers for non-fullerene solar cells

다국어 초록 (Multilingual Abstract)

In this study, a new acceptor unit, alkyl benzo[c][1,2,5]thiadiazole-5-carboxylate (BT-Est), was designed and synthesized by drafting mono alkoxy-carboxylate substituent on 5-position of BT core. Its compatibility in the conjugated system was investigated by co-polymerizing BT-Est with well-known benzo[1,2-b:4,5-b']dithiophene monomers with different alkyl chains to form polymers, P1 and P2, respectively The BT-Est yielded polymers with good solubility, medium bandgap and deep HOMO energy levels (upto -5.54 eV). Among the polymers, P1 exhibited broader absorption, compact molecular packing and high charge carrier mobility. Consequently, the best power-conversion efficiency of 6.9% were obtained for P1-based devices with non-fullerene acceptor ITIC. Our results demonstrated that the mono carboxylate-substitution on the BT core can be used as the alternate strategy to modulate the optoelectronic properties and control the aggregation in the conjugated polymers.