Structural Investigation of 1,1′-Biphenyl-4-thiol Self-Assembled Monolayers on Au(111) by Scanning Tunneling Microscopy and Low-Energy Electron Diffraction
Structural Investigation of 1,1′-Biphenyl-4-thiol Self-Assembled Monolayers on Au(111) by Scanning Tunneling Microscopy and Low-Energy Electron Diffraction
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DOI：
10.1021/la302821w
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发表时间：
2012-10-02
期刊：
影响因子：
3.9
通讯作者：
Turchanin, A.
中科院分区：
文献类型：
--
作者：
Matei, D. G.;Muzik, H.;Turchanin, A.
用溶液和气相沉积的方法在Au(111)表面制备了1，1‘-联苯-4-硫醇(H-(C6H4)(2)-SH)自组装单分子膜，并用扫描隧道显微镜(STM)、低能电子衍射(LEED)和X射线光电子能谱(XPS)对自组装膜进行了表征。与通常在Au(111)(根3 x根3)R30度结构上观察到的稠密堆积的烷烃-硫醇自组装膜不同，用这两种方法制备的稠密堆积的芳香族联苯硫醇自组装膜呈现出不寻常的六方(2×2)结构。在100℃热处理时，这种结构演变成(2x7根3)结构，从而形成沿1-10方向取向的高度有序的细条。真空气相沉积制备的低密度自组装膜具有六方(2×2)结构和(3根3×9)和(2根3×8)晶胞的两种矩形排列的混合结构。在类似于100℃的温度下，观察到有利于(2根3×8)结构的(3根3×9)结构的消光。
Self-assembled monolayers (SAMs) of 1,1'-biphenyl-4-thiol (H-(C6H4)(2)-SH) on Au(111) were prepared from solution or via vapor deposition in ultrahigh vacuum and characterized by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS). In contrast to the typically observed for densely packed alkane-thiol SAMs on Au(111) (root 3 x root 3)R30 degrees structure, the densely packed aromatic biphenylthiol SAMs prepared by both methods exhibit an unusual hexagonal (2 x 2) structure. Upon annealing at 100 degrees C, this structure evolves into the (2 x 7 root 3) structure resulting in the formation of highly ordered pinstripes oriented along the < 1 -1 0 > directions. Lower density SAMs, prepared by vapor deposition in vacuum, show mixed structures comprising the hexagonal (2 x 2) structure and two rectangular arrangements with the unit cells of (3 root 3 x 9) and (2 root 3 x 8). An extinction of the (3 root 3 x 9) structure in the favor of the (2 root 3 x 8) structure is observed upon annealing at temperatures of similar to 100 degrees C.