Two angular-shaped 4,9-didodecyl α-aNDT and 4,9-didodecyl β-aNDT isomeric structures have been regiospecifi cally designed and synthesized. The distannylated α-aNDT and β-aNDT monomers are copolymerized with the Br-DTNT monomer by the Stille coupling to furnish two isomeric copolymers, PαNDTDTNT and PβNDTDTNT, respectively. The geometric shape and coplanarity of the isomeric α-aNDT and β-aNDT segments in the polymers play a decisive role in determining their macroscopic device performance. Theoretical calculations show that PαNDTDTNT possesses more linear polymeric backbone and higher coplanarity than PβNDTDTNT. The less curved conjugated main chain facilitates stronger intermolecular π-π interactions, resulting in more redshifted absorption spectra of PαNDTDTNT in both solution and thin fi lm compared to the PβNDTDTNT counterpart.

P4,9-βNDTDTFBT:PC71BM-based solar cell device achieves a high PCE of 7.23%.

Synthesis of a new heptacyclic ladder-type di(thienobenzo)fluorene arene and its copolymers with photovoltaic/transistor properties is presented.

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