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在半金属衬底上四联苯分子的手性自组装
发表时间：2024-01-16 浏览量：438 下载量：77
| 全部作者： | 邹智星，王浩，王俊忠 |
| 作者单位： | 西南大学物理科学与技术学院 |
| 摘 要： | 本文利用低温扫描隧道显微镜（low temperature scanning tunneling microscopy，LT-STM）研究了四联苯分子在半金属Bi(111)表面上的超分子手性及其自组装结构。在极低的覆盖度下，四联苯分子形成纳米尺度的分子团簇，团簇中的分子有平躺和侧躺的取向。随着覆盖度的增加，四联苯分子形成多畴的自组装单层结构。自组装单层的基本结构单元是由两个平躺分子和一个侧躺分子构成的三聚体。高分辩的STM图表明，平躺的四联苯分子表现出结构对称性，而侧躺的四联苯分子表现为四个之字形的突起，表明四个苯环之间发生了扭曲，使得三聚体团簇具有超分子手性。有趣的是，在畴区内部相邻两个三聚体的手性相反；在畴界两侧两个三聚体的手性相同，表明同手性的三聚体之间存在空间位阻作用。当覆盖度增加到一个满层，畴界不复存在，整个分子单层形成长程有序的消旋结构。此外，由于分子与半金属衬底之间较弱的相互作用，无论是侧躺的分子还是平躺的分子，都会受到针尖电场的影响发生移动或转动。上述研究结果为理解四联苯分子和半金属之间的相互作用，超分子手性和分子自组装结构之间的关联，以及制备长程有序的界面结构提供了重要信息。 |
| 关 键 词： | 凝聚态物理；超分子手性；四联苯；自组装；扫描隧道显微镜（STM）；分子操纵 |
| Title： | Chiral self-assembly of p-quaterphenyl on semimetal surface |
| Author： | ZOU Zhixing, WANG Hao, WANG Junzhong |
| Organization： | School of Physical Science and Technology, Southwest University |
| Abstract： | The supramolecular chirality and self-assembly of p-quaterphneyl on the semimetallic Bi(111) surface have been investigated with a low temperature scanning tunneling microscopy (LT-STM). It is found that, at very low coverage, there are flat-lying and edge-on molecules in the nanoclusters of p-quaterphneyl. With the coverage increasing, p-quaterphneyl molecules form the self-assembled structure with multiple domains. The building blocks of self-assemblies are molecular trimer with two flat-lying and one edge-on molecules. High-resolution STM images demonstrate that the flat-lying molecules have a planar achiral structure, while the edge-on molecules have a zigzag and twisted chiral structure, which result in the supramolecular chirality of p-quaterphneyl trimers. Interestingly, the neighboring trimers inside the domains reveal opposite chirality, while the same chirality appears for the trimers at the domain boundaries, indicating the steric hindrance between the trimers with same handedness. When the coverage is increased to a full monolayer, the domain boundaries disappear from the self-assembled racemate structure without domain boundaries. Moreover, due to the weak molecule-substrate interaction, both the flat-lying and the edge-on molecules can be moved or rotated under the electrical filed of STM tip. These results provide important information for the understanding of interaction between p-quaterphneyl and Bi(111) surface, the correlation between the supramolecular chirality and self-assembly, and realization of the organic-metal interface with long-range order. |
| Key words： | condensed matter physics; supramolecular chirality; p-quaterphenyl; self-assembly; scanning tunneling microscopy (STM); molecular manipulation |
| 发表期数： | 2023年12月第4期 |
| 引用格式： | 邹智星，王浩，王俊忠. 在半金属衬底上四联苯分子的手性自组装[J]. 中国科技论文在线精品论文，2023，16（4）：477-487. |
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