Quaterrylene molecules on Ag(111): self-assembly behavior and voltage pulse induced trimer formation
Quaterrylene molecules on Ag(111): self-assembly behavior and voltage pulse induced trimer formation
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Ag(111) 上的四萘嵌苯分子：自组装行为和电压脉冲诱导三聚体形成
DOI：
10.1039/c8cp01005f
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发表时间：
2018
影响因子：
3.3
通讯作者：
Zhong Dingyong
中科院分区：
文献类型：
--
作者：
He Yangyong;Cai Zeying;Shao Jian;Xu Li;She Limin;Zheng Yue;Zhong Dingyong
用扫描隧道显微镜(STM)和密度泛函理论(DFT)方法研究了四氢呋喃(QR)分子在Ag(111)表面的自组装行为。结果表明，在78K时，QR分子在Ag(111)表面具有很高的流动性，由于分子间相互排斥作用，表面没有形成有序的组装结构，其亚单分子层覆盖率高达0.8个单分子层，而在一个单分子层覆盖率处观察到有序的分子结构。根据我们的密度泛函计算，底物和吸附的QR分子之间发生了电荷转移。结果在界面处出现了离面偶极子，这归因于QR分子之间的排斥偶极-偶极相互作用。此外，由于QR分子的平面构型，QR分子在Ag(111)面上的扩散势垒相对较低。通过在隧道间隙之间施加电压脉冲，QR分子发生固定和聚集，从而形成三角形三聚体。我们的工作证明了在单分子水平上操纵分子间排斥和吸引相互作用的能力。
The self-assembly behavior of quaterrylene (QR) molecules on Ag(111) surfaces has been investigated by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. It is found that the QR molecules are highly mobile on the Ag(111) surface at 78 K. No ordered assembled structure is formed on the surface with a sub-monolayer coverage up to 0.8 monolayer due to the intermolecular repulsive interactions, whereas ordered molecular structures are observed at one monolayer coverage. According to our DFT calculations, charge transfer occurs between the substrate and the adsorbed QR molecule. As a result, out-of-plane dipoles appear at the interface, which are ascribed to the repulsive dipole–dipole interactions between the QR molecules. Furthermore, due to the planar geometry, the QR molecules exhibit relatively low diffusion barriers on Ag(111). By applying a voltage pulse between the tunneling gap, immobilization and aggregation of QR molecules take place, resulting in the formation of a triangle-shaped trimer. Our work demonstrates the ability of manipulating intermolecular repulsive and attractive interactions at the single molecular level.