Two dimensional covalent organic framework (2D COF) films based on triphenylamine are considered to be promising electrochromic and energy-storage materials owing to their interlayer π–π electron delocalization, one-dimensional (1D) nanopores, and stable chemical structures. Triphenylamine-based 2D COF electrochromic films, nevertheless, rarely exhibit transparency and high optical contrast, which severely limited the scope of their application. In this work, two directly grown triphenylamine-based polyimide 2D COF films, TAPA-PMDA and TAPA-NTCDA PI COF, were prepared through solvothermal technology. Their morphologies were assembled into hierarchical nanoporous structures in the form of strips and gravel-like nanograins, respectively. Both the TAPA-PMDA and TAPA-NTCDA PI COF films exhibited a transparent bleached state and high optical contrast. Their optical contrasts were 77.6% at 752 nm and 60.4% at 708 nm, respectively. Interestingly, the TAPA-NTCDA PI COF film could exhibit multicolors (transparent, red-gray, and blue-gray) through regulating the contributions of the electron transition from HOMO to SOMO and HOMO-1 to SOMO of TPA^+•. In addition, the TAPA-PMDA and TAPA-NTCDA PI COF films also displayed fast switching and colored/bleached times of 7.3/2.7 and 5.3/8.1 s, respectively. Remarkably, the TAPA-PMDA PI COF film also demonstrated large specific capacitance and excellent charge–discharge rate capabilities. The directly grown polyimide 2D COF films are enormously promising for high-performance electrochromic and energy-storage materials.

中文翻译：

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直接生长的聚酰亚胺共价有机框架薄膜，具有高电致变色和储能性能


基于三苯胺的二维共价有机框架 （2D COF） 薄膜因其层间 π-π 电子离域、一维 （1D） 纳米孔和稳定的化学结构而被认为是很有前途的电致变色和储能材料。然而，基于三苯胺的 2D COF 电致变色薄膜很少表现出透明度和高光学对比度，这严重限制了其应用范围。在这项工作中，通过溶剂热技术制备了两种直接生长的三苯胺基聚酰亚胺 2D COF 薄膜 TAPA-PMDA 和 TAPA-NTCDA PI COF。它们的形态分别以条状和砾石状纳米颗粒的形式组装成分层纳米多孔结构。TAPA-PMDA 和 TAPA-NTCDA PI COF 薄膜均表现出透明的漂白状态和高光学对比度。它们的光学对比度在 752 nm 处分别为 77.6% 和 60.4 nm。有趣的是，TAPA-NTCDA PI COF 薄膜通过调节 TPA^+• 从 HOMO 到 SOMO 和 HOMO-1 到 SOMO 的电子跃迁的贡献，可以表现出多色（透明、红灰和蓝灰）。此外，TAPA-PMDA 和 TAPA-NTCDA PI COF 胶片也分别显示出 7.3/2.7 和 5.3/8.1 秒的快速切换和彩色/漂白时间。值得注意的是，TAPA-PMDA PI COF 薄膜还表现出较大的比电容和出色的充放电倍率能力。直接生长的聚酰亚胺 2D COF 薄膜在高性能电致变色和储能材料方面前景广阔。