Xiong Yifeng, Liao Qiaobo, Huang Zhengping, Huang Xin, Ke Can, Zhu Hengtian, Dong Chenyu, Wang Haoshang, Xi Kai, Zhan Peng, Xu Fei, Lu Yanqing
National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China.
School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China.
Adv Mater. 2020 Mar;32(9):e1907242. doi: 10.1002/adma.201907242. Epub 2020 Jan 28.
2D materials exhibit superior properties in electronic and optoelectronic fields. The wide demand for high-performance optoelectronic devices promotes the exploration of diversified 2D materials. Recently, 2D covalent organic frameworks (COFs) have emerged as next-generation layered materials with predesigned π-electronic skeletons and highly ordered topological structures, which are promising for tailoring their optoelectronic properties. However, COFs are usually produced as solid powders due to anisotropic growth, making them unreliable to integrate into devices. Here, by selecting tetraphenylethylene monomers with photoelectric activity, elaborately designed photosensitive 2D-COFs with highly ordered donor-acceptor topologies are in situ synthesized on graphene, ultimately forming COF-graphene heterostructures. Ultrasensitive photodetectors are successfully fabricated with the COF -graphene heterostructure and exhibited an excellent overall performance with a photoresponsivity of ≈3.2 × 10 A W at 473 nm and a time response of ≈1.14 ms. Moreover, due to the high surface area and the polarity selectivity of COFs, the photosensing properties of the photodetectors can be reversibly regulated by specific target molecules. The research provides new strategies for building advanced functional devices with programmable material structures and diversified regulation methods, paving the way for a generation of high-performance applications in optoelectronics and many other fields.
二维材料在电子和光电子领域展现出卓越的性能。对高性能光电器件的广泛需求推动了对多种二维材料的探索。最近，二维共价有机框架（COF）作为具有预先设计的π电子骨架和高度有序拓扑结构的下一代层状材料出现，有望用于定制其光电子性能。然而，由于各向异性生长，COF通常以固体粉末形式制备，这使得它们难以可靠地集成到器件中。在此，通过选择具有光电活性的四苯基乙烯单体，在石墨烯上原位合成了精心设计的具有高度有序供体 - 受体拓扑结构的光敏二维COF，最终形成COF - 石墨烯异质结构。利用COF - 石墨烯异质结构成功制备了超灵敏光电探测器，在473 nm处具有约3.2×10 A W的光响应度和约1.14 ms的时间响应，展现出优异的整体性能。此外，由于COF的高比表面积和极性选择性，光电探测器的光传感特性可通过特定目标分子进行可逆调节。该研究为构建具有可编程材料结构和多样化调节方法的先进功能器件提供了新策略，为光电子学及许多其他领域的一代高性能应用铺平了道路。
