Park Taesung, Kang Hungu, Jeong Youngdo, Lee Changjin, Lee Youngil, Noh Jaegeun
Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea.
J Nanosci Nanotechnol. 2011 May;11(5):4333-7. doi: 10.1166/jnn.2011.3633.
Molecular-scale surface structures of self-assembled monolayers (SAMs) formed by the spontaneous adsorption of tolane disulfides (TDS) on Au(111) in a 1 mM mixed solution of ethanol/N, N'-dimethylformamide (9:1) were examined using scanning tunneling microscopy (STM). The STM study revealed that TDS SAMs formed after a 24 h immersion at room temperature were composed of two-dimensional (2D) ordered phases with inhomogeneous surface morphologies and no clear domain boundaries. However, after 2 h immersion at 50 degrees C, uniform 2D ordered domains with clear domain boundaries were observed, which could be described as c(3 x square root of 3) structures with centered rectangular unit cell. Interestingly, a unique intermediate ordered phase with a low surface coverage was also observed. After a longer immersion for 24 h at 50 degrees C, only the uniform c(3 x square root of 3) domains were observed with a corrugation that may have reflected surface reconstruction of the Au(111) surfaces. From this study, we found that 2D ordered TDS SAMs with large and uniform domains on Au(111) can be obtained by controlling the solution temperature and immersion time.
利用扫描隧道显微镜（STM）研究了在乙醇/N，N'-二甲基甲酰胺（9:1）的1 mM混合溶液中，二苯乙炔二硫化物（TDS）在Au(111)上自发吸附形成的自组装单分子层（SAMs）的分子尺度表面结构。STM研究表明，在室温下浸泡24小时后形成的TDS SAMs由具有不均匀表面形态且无清晰畴界的二维（2D）有序相组成。然而，在50℃下浸泡2小时后，观察到具有清晰畴界的均匀2D有序畴，其可描述为具有中心矩形晶胞的c(3×√3)结构。有趣的是，还观察到一种具有低表面覆盖率的独特中间有序相。在50℃下更长时间浸泡24小时后，仅观察到具有可能反映Au(111)表面重构的起伏的均匀c(3×√3)畴。通过这项研究，我们发现通过控制溶液温度和浸泡时间，可以在Au(111)上获得具有大且均匀畴的2D有序TDS SAMs。
