PDPP2T polymers post-functionalized with UPy (D0, D2, D5) for stretchable transistors

Major Contributions
 

1. Grafted ureido-pyrimidinone (UPy) units onto diketopyrrolopyrrole-based PDPP2T through a post-functionalization strategy, creating hierarchical hydrogen bonds along extended alkyl side chains: weak mid-chain urethane linkages and strong end-chain quadruple UPy.

2. The dynamic hydrogen bonds dissipate stress, giving crack resistance and elastic recovery up to 100% strain; GIWAXS shows crystallinity is largely maintained, and the backbone electronic structure is preserved.

3. D5 devices keep mobility within the same order of magnitude (3.02→1.12 × 10⁻¹ cm² V⁻¹ s⁻¹) after 500 cycles at 100% strain, while D0 loses >99%; the strategy extends to P3HT, isoindigo-, BDT- and NDI-based polymers.

主要貢獻
 

1. 以後官能化策略將脲基嘧啶酮（UPy）接枝到二酮吡咯並吡咯系 PDPP2T 高分子，在延長的烷基側鏈上形成階層式氫鍵：鏈中段為較弱的胺甲酸酯鍵，鏈末端為強四重氫鍵 UPy。

2. 動態氫鍵消散應力，使薄膜在 100% 應變下仍具抗裂性與彈性回復；GIWAXS 顯示結晶度大致維持，主鏈電子結構不受影響。

3. D5 元件在 100% 應變拉伸 500 次後，遷移率仍維持同一數量級（3.02→1.12 × 10⁻¹ cm² V⁻¹ s⁻¹），D0 則下降超過 99%；此策略也適用於 P3HT、異靛藍、BDT 與 NDI 系高分子。