Abstract Copolymerization towards producing broadly absorbing black neutrality for flexible electrochromics was investigated. Neutral-state saturated green and dark blue donor-acceptor-donor (D-A-D) polymers consisting of electron-acceptor thieno[3,4-b]pyrazine and benzo[1,2,3]triazole based units respectively, were chosen as distributed segments, simultaneous with their tendency to switch to transmissive oxidation states. Variation of the feed ratio of two precursors in a mixture solution was used to regulate the energy and spectral absorption range of electrochemical copolymerization films. Co-polymer PEM-11 in 1:1 monomer feed ratio demonstrated a full range of visible absorption, and switched between an improved saturated black neutral state (L* = 43.68, a* = 4.98, b* = −13.13) and a light gray transmissive oxidation state (L* = 67.30, a* = −1.36, b* = 1.67) reversibly, where L* represents white to black balance, a* red to green and b* yellow to blue, with the optical contrast of 35% at 590 nm and switching speed as low as 0.6 s. Furthermore, the PEM-11 film exhibited stable n-doping, favorable cycle stability, and a lower electrochemical/optical band-gap (0.80 eV/1.21 eV) in comparison with the reported individual neutral black ECPs. The results suggested that the as-obtained copolymer could be a promising candidate for electrochromic windows, e-papers, or eyewear applications.

中文翻译：

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通过两种供体-受体型单体的电化学共聚，对具有优异电致变色性能的黑色至透射共轭共聚物进行颜色调节

摘要 研究了为柔性电致变色材料产生广泛吸收的黑色中性的共聚反应。分别由电子受体噻吩并[3,4-b]吡嗪和苯并[1,2,3]三唑基单元组成的中性饱和绿色和深蓝色供体-受体-供体（DAD）聚合物被选为分布式链段，同时它们倾向于转换为透射氧化态。混合溶液中两种前体的进料比的变化用于调节电化学共聚膜的能量和光谱吸收范围。单体进料比为 1:1 的共聚物 PEM-11 表现出全范围的可见光吸收，并在改进的饱和黑色中性状态 (L* = 43.68, a* = 4.98, b* = -13.13) 和光灰色透射氧化态（L* = 67.30，a* = -1。36, b* = 1.67) 可逆，其中 L* 代表白到黑平衡，a* 代表红到绿，b* 代表黄到蓝，在 590 nm 处的光学对比度为 35%，切换速度低至 0.6 s。此外，与报道的单个中性黑色 ECP 相比，PEM-11 薄膜表现出稳定的 n 掺杂、良好的循环稳定性和较低的电化学/光学带隙（0.80 eV/1.21 eV）。结果表明，所获得的共聚物可能是电致变色窗、电子纸或眼镜应用的有希望的候选者。与报道的单个中性黑色 ECP 相比，电化学/光学带隙 (0.80 eV/1.21 eV) 更低。结果表明，所获得的共聚物可能是电致变色窗、电子纸或眼镜应用的有希望的候选者。与报道的单个中性黑色 ECP 相比，电化学/光学带隙 (0.80 eV/1.21 eV) 更低。结果表明，所获得的共聚物可能是电致变色窗、电子纸或眼镜应用的有希望的候选者。