Synergetic Evolution of Diketopyrrolopyrrole-Based Polymeric Semiconductor for High Reproducibility and Performance: Random Copolymerization of Similarly Shaped Building Blocks.

A new random copolymer consisting of similarly shaped donor-acceptor building blocks of diketopyrrolopyrrole-selenophene-vinylene-selenophene (DPP-SVS) and DPP-thiophene-vinylene-thiophene (DPP-TVT) is designed and synthesized. The resulting P-DPP-SVS(5)-TVT(5) with an equal molecular ratio of the two building blocks produced significantly enhanced solubility when compared to that of the two homopolymers, PDPP-SVS and PDPP-TVT. More importantly, despite the maximum segmental randomness of the PDPP-SVS(5)-TVT(5) copolymer, its crystalline perfectness and preferential orientation are outstanding, even similar to those of the homopolymers thanks to the similarity of the two building blocks.

Structure-property relationships: asymmetric alkylphenyl-substituted anthracene molecules for use in small-molecule solar cells.

Two asymmetric anthracene-based organic molecules, NDHPEA and TNDHPEA, were prepared without or with a thiophene spacer between the anthracene and naphthalene units. These asymmetric oligomers displayed different degrees of coplanarity, as evidenced by differences in the dihedral angles calculated by using DFT. Differential scanning calorimetry and XRD studies were used to probe the crystallization characteristics and molecular packing structures in the active layers.