Fast Synthesis\nof Olefin-Linked Covalent Organic Frameworks\nvia Supercritically Solvothermal Polymerization

Covalent organic frameworks (COFs) are newly emerging\nyet rapidly\ndeveloped porous crystalline polymeric materials, which feature topological\ndesignability, structural diversity, and porosity tunability. However,\nmost of the reported COFs hitherto are prepared by a solvothermal\nmethod, which needs a long reaction time, especially for the olefin-linked\nCOFs, which hinders their practical applications. Herein, we report\nthe fast growth of olefin-linked COFs synthesized by the supercritical\nsolvothermal method under supercritical carbon dioxide conditions.\nVia optimization of the reaction conditions, olefin-linked COFs are\nprepared within 6 h, which is period much shorter than that of the\ntraditional solvothermal method. The as-obtained COFs feature two\ndistinct morphologies, namely, spherical and rod-like. Interestingly,\nthe rod-like crystal shows polarized light extinction and rebrightening\nphenomena, indicating the high crystallinity. After being doped with\nI<sub>2</sub>, the obtained I<sub>2</sub>@COF<sub>TMT‑PA</sub> shows a Hall mobility of 1.94 cm<sup>2</sup> V<sup>–1</sup> S<sup>–1</sup>, indicating its potential applications in\noptoelectronics. This work expands the application of the supercritically\nsolvothermal method to the fast growth of olefin-linked COFs and solves\na long-standing challenge in chemical science, which opens up opportunities\nfor basic research as well as practical applications of olefin-linked\nCOFs and other polymeric materials.