Wang Lu, Wang Xiang, Zhao Zhen-Lian, Wan Li-Jun, Wang Dong
CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2024 May 22;146(20):14079-14085. doi: 10.1021/jacs.4c02418. Epub 2024 May 8.
Insights into the formation mechanisms of two-dimensional covalent organic frameworks (2D COFs) at both the in-plane and interlayer levels are essential for improving material quality and synthetic methodology. Here, we report the controllable preparation of 2D COF films via on-surface synthesis and investigate the growth mechanism using atomic force microscopy. Monolayer, bilayer, and layer-plus-island multilayer COF films were successfully constructed on hexagonal boron nitride in a controlled manner. The porphyrin-based COF films grow in the Stranski-Krastanov mode, i.e., a uniform bilayer COF film can be formed through layer-by-layer growth in the initial stage followed by island growth starting from the third layer. Furthermore, fluorescence quenching caused by π-π stacking interactions between 2D COF neighboring layers was revealed. These results provide new perspectives on the synthesis of high-quality 2D COF films with controllable thickness and morphology, paving the way for a diverse range of applications.
深入了解二维共价有机框架（2D COF）在平面内和层间水平的形成机制对于提高材料质量和合成方法至关重要。在此，我们报告了通过表面合成可控制备2D COF薄膜，并使用原子力显微镜研究其生长机制。单层、双层和层加岛多层COF薄膜已成功以可控方式在六方氮化硼上构建。基于卟啉的COF薄膜以斯特兰斯基-克拉斯坦诺夫模式生长，即初始阶段可通过逐层生长形成均匀的双层COF薄膜，从第三层开始随后进行岛状生长。此外，还揭示了2D COF相邻层之间的π-π堆积相互作用导致的荧光猝灭。这些结果为合成具有可控厚度和形态的高质量2D COF薄膜提供了新的视角，为广泛的应用铺平了道路。
