Two-dimensional alkylated αβ-TTN and βα-TTN were designed and synthesized. The cross-shaped αβ-TTN and βα-TTN moieties were polymerized to afford two isomeric polymers, Pαβ-TTNFBT 40 and Pβα-TTNFBT 40 . Pαβ-TTNFBT 40 using an α-aNDT unit in the main chain exhibited more red-shifted absorption and a smaller HOMO/LUMO band gap than Pβα-TTNFBT 40 using β-aNDT in the main chain. Compared to Pβα-TTNFBT 40 showing a curved backbone, density functional theory (DFT) calculations revealed that Pαβ-TTNFBT 40 exhibited a quasi-linear polymeric backbone that induces stronger intermolecular interactions and higher molecular ordering in the solid state. Pαβ-TTNFBT 40 exhibited an organic field-effect transistor (OFET) hole mobility of 1.12 × 10 −2 cm 2 V −1 s −1 , which outperformed Pβα-TTNFBT 40 by 1 order of magnitude (1.60 × 10 −3 cm 2 V −1 s −1 ). Through side-chain engineering and optimization, Pαβ-TTNFBT 24 using a shorter 2-butyloctyl side chain further strengthened the intermolecular interactions. From grazing incidence wide-angle X-ray scattering (GIWAXS), Pαβ-TTNFBT 24 adopted an edge-on π−π stacking orientation in a thin film, leading to an improved mobility of 1.75 × 10 −1 cm 2 V −1 s −1 , which has exceeded the mobility of the one-dimensional α-aNDT-based PaNDTDTFBT (4.70 × 10 −2 cm 2 V −1 s −1 ). This research demonstrated that the twodimensional structure is an effective strategy to achieve higher OFET mobility, and the geometry of the main chain played a more significant role than that of the side chain in determining the physical and packing properties of polymers.

No abstract

Sequence-controlled polychalcogenophenes have attracted much interest in terms of synthesis, structure and function in polymer science. For the first time, we unprecedentedly developed a new class of alternating block conjugated...

No abstract

No abstract