A series of donor–acceptor polymers incorporating the thieno[3,2‐b]thiophene‐2,5‐dione (TTD) acceptor unit and different donor units are synthesized. The synthesis of a TTD‐based key monomer, 3,6‐bis(5‐bromo‐4‐alkylthiophen‐2‐yl)thieno[3,2‐b]thiophene‐2,5‐dione, is successfully improved to afford higher total yield with less reaction steps (42%/4 steps) than those previously reported (14%/7 steps). The polymers exhibit low‐lying lowest unoccupied molecular orbital (LUMO) energy levels of around −3.8 eV and highest occupied molecular orbital (HOMO) energy levels ranging from −5.49 to −5.14 eV. Organic field‐effect transistors based on the polymers exhibit ambipolar characteristics with high hole and electron mobilities in the order of 10⁻¹ cm² V⁻¹ s⁻¹ in air. These high mobilities can be attributed to the formation of highly crystalline lamellar structure with preferential edge‐on orientation of the polymer thin films. Interestingly, the ratio of the electron to hole mobilities decreases with the extension of the donor units. This can be explained by the distribution of HOMOs and LUMOs along the backbones. Additionally, complementary inverters using the polymers with well‐balanced ambipolar characteristics exhibit sharp switching characteristics with high gain of ≈140 at the supply voltage of 40 V.

中文翻译：

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噻吩并噻吩-2,5-二酮基供体-受体聚合物：改进的合成以及供体单元对双极电荷传输性质的影响

合成了一系列结合噻吩并[3,2 - b ]噻吩-2,5-二酮（TTD）受体单元和不同供体单元的供体-受体聚合物。基于TTD-键单体，3,6-双（5-溴-4- alkylthiophen -2-基）噻吩并[3,2-的合成b ]噻吩-2,5-二酮，成功地提高了，得到更高总收率与之前报道的反应步骤（14％/ 7步）相比，反应步骤更少（42％/ 4步）。这些聚合物的低位最低未占据分子轨道（LUMO）能级约为-3.8 eV，最高位占据的分子轨道（HOMO）能级介于-5.49至-5.14 eV之间。基于聚合物的有机场效应晶体管表现出双极性特性，具有高空穴和电子迁移率，约为10 ^-1 cm ²空气中的V ^-1 s ^-1。这些高迁移率可归因于高度结晶的层状结构的形成，并具有聚合物薄膜优先的边沿取向。有趣的是，电子与空穴迁移率之比随着施主单元的延伸而降低。这可以通过沿主干的HOMO和LUMO的分布来解释。此外，使用具有良好平衡双极性特性的聚合物的互补逆变器在40 V的电源电压下具有清晰的开关特性，并具有约140的高增益。