Homogeneous Dispersion of Aromatic Thiolates in the Binary Self-Assembled Monolayer on Au(111) via Displacement Revealed by Tip-Enhanced Raman Spectroscopy
Homogeneous Dispersion of Aromatic Thiolates in the Binary Self-Assembled Monolayer on Au(111) via Displacement Revealed by Tip-Enhanced Raman Spectroscopy
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DOI：
10.1021/acs.jpcc.0c01507
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发表时间：
2020-06-18
影响因子：
3.7
通讯作者：
Kim, Yousoo
中科院分区：
文献类型：
--
作者：
Hong, Misun;Yokota, Yasuyuki;Kim, Yousoo
芳香硫醇自组装单层（sam）在金属表面作为覆盖功能层的兴趣。与烷烃硫醇不同，芳香硫醇的多组分SAMs尚未得到全面的研究，特别是在形成过程和组分的表面分布方面。本文采用置换法研究了由简单芳香硫醇、苯乙硫醇（BT）和苯乙硫醇（BMT）制备的Au（111）表面二元sam的表面结构和化学状态。我们利用基于扫描隧道显微镜（STM）的尖端增强拉曼光谱（TERS）在环境条件下探测有关振动指纹和形态的局部表面信息。STM可视化了BMT吸附和脱附后的形态变化，因为附原子岛被破坏，在下面的Au上出现了空位岛（111）。用透射电镜研究了两种硫代酸盐在二元硫代酸盐中的混合态，证明了BMT对BT的易位移和它们在二元硫代酸盐中的均匀分散。因此，利用TERS和STM分析的互补分析结果为Au（111）上的二元芳硫酸盐sam提供了基本信息。
Self-assembled monolayers (SAMs) of aromatic thiols on metal surfaces are of interest as covering functional layers. Unlike alkanethiols, multicomponent SAMs of aromatic thiols have not been comprehensively studied, especially regarding formation processes and the surface distribution of the components. In this work, we investigated the surface structures and chemical states of binary SAMs on Au(111) made from simple aromatic thiols, benzenethiol (BT), and benzenemethanethiol (BMT), via a displacement method. We utilized tip-enhanced Raman spectroscopy (TERS) based on scanning tunneling microscopy (STM) under ambient conditions for probing local surface information regarding vibrational fingerprints as well as morphologies. STM visualized morphological changes upon adsorption of BMT and desorption of BT as adatom islands were destructed and vacancy islands emerged on the underlying Au(111). The mixture states of two thiolates in the SAM were investigated using TERS, which demonstrates the facile displacement of BT by BMT and their homogeneous dispersion in the binary SAMs. Thus, the complementary analytical results using TERS and STM analyses provided fundamental information on the binary aromatic thiolate SAMs on Au(111).