Towards single-crystalline two-dimensional poly(arylene vinylene) covalent organic frameworks
Shaik Ghouse, Ziang Guo, Sergio Gámez-Valenzuela, David Mücke, Bowen Zhang, Lei Gao, Silvia Paasch, Yubin Fu, Chuanhui Huang, Chandrashekar Naisa, Eike Brunner, M. Bonn, M. Carmen Ruiz Delgado, Junliang Sun, Ruqiang Zou, Ute Kaiser, Mingchao Wang, Xinliang Feng
Abstract
Abstract Vinylene-linked two-dimensional (2D) conjugated covalent organic frameworks, or 2D poly(arylene vinylene)s (2D PAVs), are promising polymer semiconductors for (opto-)electronics, photocatalysis and electrochemistry. However, conventional solvothermal synthesis often produces 2D PAVs that are poorly crystalline or difficult to access. Here we introduce a Mannich-elimination strategy that converts 8 2D imine-covalent organic frameworks into 11 highly crystalline 2D PAVs though a reversible C=C bond formation mechanism enabling precise crystallization control. This versatile approach affords robust 2D PAVs with honeycomb, square or kagome lattices, specific surface area up to ∼2,000 m 2 g −1 and lattice-mismatch tolerance up to 3.5%. High-resolution transmission electron microscopy and continuous rotation electron diffraction reveal molecular-level ordering in a 2-µm-sized triphenylbenzene-based single-crystalline 2D PAV. We demonstrate that crystallinity profoundly influences charge transport, with benzotrithiophene-based 2D PAVs exhibiting charge mobilities tenfold higher than their amorphous analogues or 2D polyimine precursors. This work establishes a general route to highly crystalline 2D conjugated polymer materials for robust applications.