物理化学学报 >> 2022, Vol. 38 >> Issue (8): 2011060.doi: 10.3866/PKU.WHXB202011060

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Ag(111)表面Ag配位结构的分等级组装

李若宁1, 张雪1, 薛娜2, 李杰3, 吴天昊1, 徐榛1, 王一帆1, 李娜1, 唐浩4, 侯士敏1,3,*(), 王永锋1,5,*()   

  1. 1 北京大学电子学系, 纳米器件物理与化学教育部重点实验室, 碳基电子学中心, 北京 100871
    2 天津第五中心医院, 天津市早产儿器官发育表观遗传学重点实验室中心实验室, 天津 300450
    3 北京大学(天津滨海)新一代信息技术研究院, 天津 300450
    4 法国国家科学研究中心, 材料与结构研究所, 表界面纳米研究组, 图卢兹 31055, 法国
    5 北京量子信息科学研究院, 北京 100193
  • 收稿日期:2020-11-23 录用日期:2020-12-01 发布日期:2020-12-14
  • 通讯作者: 侯士敏,王永锋 E-mail:smhou@pku.edu.cn;yongfengwang@pku.edu.cn
  • 基金资助:
    中国科学技术部(2018YFA0306003);中国科学技术部(2017YFA0205003);国家自然科学基金(21972002);国家自然科学基金(21902003);国家自然科学基金(22002109)

Hierarchical Self-Assembly of Ag-Coordinated Motifs on Ag(111)

Ruoning Li1, Xue Zhang1, Na Xue2, Jie Li3, Tianhao Wu1, Zhen Xu1, Yifan Wang1, Na Li1, Hao Tang4, Shimin Hou1,3,*(), Yongfeng Wang1,5,*()   

  1. 1 Key laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics, Department of Electronics, Peking University, Beijing 100871, China
    2 Central Laboratory, Tianjin Key Laboratory of Epigenetics for Organ Development in Preterm Infants, the Fifth Central Hospital of Tianjin, Tianjin 300450, China
    3 Peking University Information Technology Institute (Tianjin Binhai), Tianjin 300450, China
    4 SINANO Group, CEMES/CNRS, Toulouse 31055, France
    5 Beijing Academy of Quantum Information Sciences, Beijing 100193, China
  • Received:2020-11-23 Accepted:2020-12-01 Published:2020-12-14
  • Contact: Shimin Hou,Yongfeng Wang E-mail:smhou@pku.edu.cn;yongfengwang@pku.edu.cn
  • About author:Email: yongfengwang@pku.edu.cn. Tel.: +86-10-62762722 (Y.W.)
    Email: smhou@pku.edu.cn (S.H.)
  • Supported by:
    the Ministry of Science and Technology of China(2018YFA0306003);the Ministry of Science and Technology of China(2017YFA0205003);the National Natural Science Foundation of China(21972002);the National Natural Science Foundation of China(21902003);the National Natural Science Foundation of China(22002109)

摘要:

表面辅助的金属有机纳米结构因其结构稳定性和潜在应用受到广泛关注。在金属有机纳米结构中,金属原子来源于外部沉积的金属或金属表面原子。外部沉积的金属原子种类多样,取决于目标纳米结构。然而,金属表面原子受限于表面科学常用的金、银和铜单晶金属表面。金属有机纳米结构大多包括Au配位或是Cu配位结构,而只有少量的用表面Ag原子构成。分子金属相互作用的进一步研究有助于预期纳米结构的精确控制形成。至于构建基元,有机分子通过M―C、M―N和M―O键与表面金属原子配位。末端炔反应或者乌尔曼耦合能够实现C―M―C节点的形成。Cu和Au原子能够与含有末端氰基或吡啶基官能团的分子配位形成N―M―N键。另外,表面Ag增原子能够通过Ag―N配位键与酞菁分子配位。然而,M―O配位键的相关研究较少。因此,我们计划使用末端羟基分子与Ag增原子配位形成金属有机配位纳米结构去研究O―Ag节点。我们通过扫描隧道显微镜利用4, 4’-二羟基-1, 1’: 3’, 1’’-三联苯分子(4, 4’-dihydroxy-1, 1’: 3’, 1’’-terphenyl,H3PH)和Ag增原子成功构筑了一系列二维有序纳米结构。在室温下,蒸镀的H3PH分子自组装形成由环氢键连接的密堆积结构。当退火温度提升到330 K,一种新的纳米结构出现了,该结构由O―Ag配位键和氢键共同作用形成。进一步地提升退火温度至420 K,蜂巢结构和共存的二重配位链出现,这两种结构中仅由O―Ag―O键构成。为分析金属分子反应路径和O―Ag―O键的能量势垒,我们对该体系进行密度泛函理论计算。计算结果显示,O―Ag键形成的能量势垒是1.41 eV,小于O―Ag―O节点1.85 eV的能量势垒。这也解释了分等级金属-有机纳米结构形成的原因。我们的实验结果提供了一种利用有机小分子和金属增原子来设计和构筑分等级二维纳米结构的有效方法。

关键词: 退火, 环氢键, 配位, 扫描隧道显微镜, 密度泛函理论

Abstract:

Metal-organic nanostructures on surfaces have attracted considerable attention owing to their structural stability and potential applications. In metal-organic nanostructures, metal atoms are derived from the externally deposited metals or native surface atoms. Externally deposited metals are of rich diversity and depend on the targeted nanostructures. However, native surface atoms are restricted to single-crystalline metal surfaces of gold, silver, and copper, which are usually used in surface science. Metal-organic nanostructures mostly consist of Au- or Cu-coordinated motifs, while only a few consist of surface Ag atoms. Further investigation into the molecule-metal interactions is beneficial for the accurately controlled fabrication of the desired nanostructure. As for the building blocks, organic molecules coordinate with native surface atoms by M―C, M―N, and M―O bonds. The reactions of terminal alkynes or Ullmann couplings could realize the formation of C―M―C linkages. Cu and Au atoms could coordinate with molecules with terminal cyano or pyridyl groups to form N―M―N bonds. In addition, surface Ag adatoms could coordinate with phthalocyanine through Ag―N bonds. However, a comprehensive study of M―O coordination bonds is still lacking. Thus, we used hydroxyl-terminated molecules to coordinate with Ag adatoms to form metal-organic coordination nanostructures and study the O―Ag linkages. In this case, we successfully built and investigated a series of ordered structures by depositing 4, 4'-dihydroxy-1, 1': 3', 1''-terphenyl (H3PH) molecules on the Ag(111) surface by scanning tunneling microscopy. At room temperature, a close-packed ordered structure was formed by H3PH molecules through cyclic hydrogen bonds, and the repeat unit of such nanostructures contained eight H3PH molecules. Upon increasing the annealing temperature, the formation of O―Ag bond led to a change in the self-assembly pattern. When the annealing temperature was increased to 330 K, a new ordered nanostructure occurred due to the combination of O―Ag coordination and hydrogen bonds. Upon further increasing the annealing temperature to 420 K, a honeycomb structure and coexisting two-fold coordination chains appeared, which only consisted of O―Ag―O linkages. Density functional theory calculations were carried out to analyze the metal-molecule reaction pathways and energy barriers of the O―Ag―O bonds. The energy barrier of the O―Ag bond is 1.41 eV, which is less than that of the O―Ag―O linkage calculated to be 1.85 eV. The low energy barrier of the O―Ag bond and large coordination energy of the O―Ag―O linkage can be attributed to the formation of the hierarchical metal-organic nanostructure. The results obtained herein provide an effective approach for designing and building two-dimensional hierarchical structures with organic small molecules and metal adatoms on single-crystalline metal surfaces.

Key words: Annealing, Cyclic hydrogen bond, Coordination, Scanning tunneling microscopy, Density functional theory

MSC2000: 

  • O649