Conjugated polymers synthesized through random terpolymerization have recently attracted great research interest due to the synergetic effect on the polymer’s crystallinity and semiconducting properties. Several studies have demonstrated the efficacy of random terpolymerization in fine-tuning the aggregation behavior and optoelectronic property of conjugated polymers to yield enhanced device performance. However, as an influential approach of backbone engineering, its efficacy in modulating the mobility–stretchability property of high-performance conjugated polymers has not been fuller explored to date. Herein, a series of random terpolymers based on the diketopyrrolopyrrole-bithiophene (DPP-2T) backbone incorporating different amounts of isoindigo (IID) unit are synthesized, and their structure–mobility–stretchability correlation is thoroughly investigated. Our results reveal that random terpolymers containing a low IID content (DPP95 and DPP90) show enhanced interchain packing and solid-state aggregation to result in improved charge-transporting performance (can reach 4 order higher) compared to the parent polymer DPP100. In addition, owing to the enriched amorphous feature, DPP95 and DPP90 deliver an improved orthogonal mobility (μ_h) of >0.01 cm² V^–1 s^–1 under a 100% strain, higher than the value (∼0.002 cm² V^–1 s^–1) of DPP100. Moreover, DPP95 even yields 20% enhanced orthogonal μ_h retention after 800 stretching–releasing cycles with 60% strain. As concluded from a series of analyses, the improved mobility–stretchability property exerted by random terpolymerization arises from the enriched amorphous feature and enhanced aggregation behavior imposed by the geometry mismatch between different acceptors (DPP and IID). This study demonstrates that backbone engineering through rational random terpolymerization not only enhances the mobility–stretchability of a conjugated polymer but also realizes a better mechanical endurance, providing a new perspective for the design of high-performance stretchable conjugated polymers.

中文翻译：

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基于二酮吡咯并吡咯的共轭聚合物的骨架工程，通过无规三元聚合提高了迁移率-拉伸性

通过无规三元聚合合成的共轭聚合物由于对聚合物的结晶度和半导体性能的协同作用，最近引起了极大的研究兴趣。几项研究证明了无规三元聚合在微调共轭聚合物的聚集行为和光电性能以提高器件性能方面的功效。然而，作为骨干工程学的一种有影响的方法，迄今为止，其在调节高性能共轭聚合物的迁移率-可拉伸性方面的功效尚未得到充分的探索。在此，我们合成了一系列基于二酮吡咯并吡咯-联噻吩（DPP-2T）骨架的无规三元共聚物，其中掺入了不同量的异靛蓝（IID）单元，并对其结构-迁移率-可拉伸性的相关性进行了彻底的研究。我们的结果表明，与母体聚合物DPP100相比，具有低IID含量的无规三元共聚物（DPP95和DPP90）显示出增强的链间堆积和固态聚集，从而改善了电荷传输性能（可以提高4倍）。此外，由于具有丰富的非晶态特征，DPP95和DPP90还具有改善的正交迁移率（μ在100％应变下，> 0.01 cm ² V ^–1 s ^–1的_h）高于DPP100的值（〜0.002 cm ² V ^–1 s ^–1）。此外，甚至DPP95产生20％增强正交μ _ħ在800％拉伸释放循环后保持60％应变。从一系列分析中得出的结论是，由无规三元聚合作用产生的改善的迁移率-可拉伸性是由丰富的无定形特征和不同受体（DPP和IID）之间的几何构型不匹配所引起的增强的聚集行为引起的。这项研究表明，通过合理的无规三元聚合进行骨架工程，不仅可以增强共轭聚合物的迁移率-可拉伸性，而且可以实现更好的机械耐久性，这为高性能可拉伸共轭聚合物的设计提供了新的视角。