主催: The Japan Society of Vacuum and Surface Science
会議名: 2023年日本表面真空学会学術講演会
開催地: 名古屋
開催日: 2023/10/31 - 2023/11/02
The conformation and alignment of molecules in organic materials play a critical role, influencing the macroscopic properties of these materials. As two-dimensional (2D) materials offer a simplified model of their three-dimensional (3D) counterparts, researchers have extensively investigated the atomic-scale arrangement and alignment of molecules in 2D assemblies using scanning tunneling microscopy (STM).[1] This research is focused on the systematic exploration of the structural configuration and alignment of a donor-acceptor-type molecule, specifically 4-(3,3-dimethyl-2,3-dihydro-1H-indol-1-yl)benzonitrile (IBN), within both 2D and 3D assemblies.[2] The study focused on examination of 2D assembly of IBN on the Au(111) via STM and 3D assembly of IBN in a single crystal using X-ray crystallography (Fig. 1).
Our investigation has elucidated that IBN maintains a planar conformation in both 2D and 3D assemblies, and the dipole moment of IBN in the 2D and 3D assemblies are essentially indistinguishable. Interestingly, in both the 2D and 3D assemblies, IBN molecules align themselves in a manner that effectively cancel the net dipole moment, despite the distinct variations in their self-assembled motifs. In the 2D assemblies, the orientation and self-assembled structure of IBN are subject to influence from the surface density of IBN. Furthermore, these factors are intricately interconnected with the crystal orientation and superstructure of the Au(111) substrate, owing to the strong interaction between IBN and the Au(111) surface. Moreover, insights from scanning tunneling spectroscopy have disclosed that the coordination structure is not included in the self-assembled arrangement of IBN on Au(111) .
References
[1] W. H. Soe, Y. Shirai, C. Durand, Y. Yonamine, K. Minami, X. Bouju, M. Kolmer, K. Ariga, C. Joachim, W. Nakanishi, ACS Nano, 11, 10357 (2017).
[2] W. Nakanishi, Y. Matsushita, M. Takeuchi, K. Sagisaka, Phys. Chem. Chem. Phys., 25, 13702 (2023).
