Yang Yizhou, Sandra Amritha P, Idström Alexander, Schäfer Clara, Andersson Martin, Evenäs Lars, Börjesson Karl
Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden.
J Am Chem Soc. 2022 Sep 7;144(35):16093-16100. doi: 10.1021/jacs.2c06333. Epub 2022 Aug 25.
Two-dimensional covalent organic frameworks (2D COFs) feature graphene-type 2D layered sheets but with a tunable structure, electroactivity, and high porosity. If these traits are well-combined, then 2D COFs can be applied in electronics to realize functions with a high degree of complexity. Here, a highly crystalline electroactive COF, BDFamide-Tp, was designed and synthesized. It shows regularly distributed pores with a width of 1.35 nm. Smooth and successive films of such a COF were fabricated and found to be able to increase the conductivity of an organic semiconductor by 10 by interfacial doping. Upon encapsulation of a photoswitchable molecule (spiropyran) into the voids of the COF layer, the resulted devices respond differently to light of different wavelengths. Specifically, the current output ratio after UV vs Vis illumination reaches 100 times, thus effectively creating on and off states. The respective positive and negative feedbacks are memorized by the device and can be reprogrammed by UV/Vis illumination. The reversible photostimulus responsivity and reliable memory of the device are derived from the combination of electroactivity and porosity of the 2D COF. This work shows the capability of 2D COFs in higher-level electronic functions and extends their possible applications in information storage.
二维共价有机框架（2D COFs）具有石墨烯型二维层状结构，但结构、电活性和孔隙率可调。如果这些特性能够很好地结合，那么2D COFs可应用于电子领域，以实现高度复杂的功能。在此，设计并合成了一种高度结晶的电活性COF，即BDFamide-Tp。它具有宽度为1.35 nm的规则分布的孔隙。制备了这种COF的光滑连续薄膜，发现通过界面掺杂可使有机半导体的电导率提高10倍。将光开关分子（螺吡喃）封装到COF层的空隙中后，所得器件对不同波长的光有不同的响应。具体而言，紫外光照射与可见光照射后的电流输出比达到100倍，从而有效地产生开和关状态。器件会记住各自的正反馈和负反馈，并可通过紫外光/可见光照射重新编程。器件的可逆光刺激响应性和可靠记忆源于二维COF的电活性和孔隙率的结合。这项工作展示了二维COF在更高级电子功能方面的能力，并扩展了它们在信息存储方面的可能应用。
