Lyu Chengkun, Gao Yifan, Zhou Kun, Hua Muqing, Shi Ziliang, Liu Pei-Nian, Huang Li, Lin Nian
Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore.
Department of Physics, The Hong Kong University of Science and Technology, Hong Kong SAR 999077, China.
ACS Nano. 2024 Jul 20. doi: 10.1021/acsnano.4c05838.
Supramolecular coordination self-assembly on solid surfaces provides an effective route to form two-dimensional (2D) metal-organic frameworks (MOFs). In such processes, surface-adsorbate interaction plays a key role in determining the MOFs' structural and chemical properties. Here, we conduct a systematic study of Cu-HAT (HAT = 1,4,5,8,9,12-hexaazatriphenylene) 2D conjugated MOFs (-MOFs) self-assembled on Cu(111), Au(111), Ag(111), and MoS substrates. Using scanning tunneling microscopy and density functional theory calculations, we found that the as-formed CuHAT -MOFs on the four substrates exhibit distinctive structural features including lattice constant and molecular conformation. The structural variations can be attributed to the differentiated substrate effects on the 2D -MOFs, including adsorption energy, lattice commensurability, and surface reactivity. Specifically, the framework grown on MoS is nearly identical to its free-standing counterpart. This suggests that the 2D van der Waals (vdW) materials are good candidate substrates for building intrinsic 2D MOFs, which hold promise for next-generation electronic devices.
固体表面上的超分子配位自组装为形成二维（2D）金属有机框架（MOF）提供了一条有效途径。在这些过程中，表面吸附质相互作用在决定MOF的结构和化学性质方面起着关键作用。在此，我们对在Cu(111)、Au(111)、Ag(111)和MoS衬底上自组装的Cu-HAT（HAT = 1,4,5,8,9,12-六氮杂三亚苯）二维共轭MOF（-MOF）进行了系统研究。使用扫描隧道显微镜和密度泛函理论计算，我们发现四种衬底上形成的CuHAT -MOF表现出独特的结构特征，包括晶格常数和分子构象。结构变化可归因于二维-MOF上不同的衬底效应，包括吸附能、晶格适配性和表面反应性。具体而言，在MoS上生长的框架与其独立对应物几乎相同。这表明二维范德华（vdW）材料是构建本征二维MOF的良好候选衬底，这对下一代电子器件具有重要意义。
