2D-Highly Ordered Epitaxial Adlayers of Fullerene, Fullerene oligomer and Fullerene Polymers Prepared by "Wet Process"

为了在单晶金属表面形成高度有序的富勒烯及其衍生物和其他芳香族分子的外延层，开发和研究了由朗缪尔膜简单转移组成的“湿法”技术。我们发现，在空气-水界面的朗缪尔膜的简单转移使我们能够在环境条件下在Au(111)表面上制备富勒烯的外延层。在此基础上，提出了改进的“湿法”--“电化学置换法”。该方法包括在空气-水界面上将C_60的朗缪尔膜转移到碘修饰的Au(111)表面，然后在溶液中电化学去除和从碘表面置换到C_60表面。用该方法制备的C_(60)薄膜具有良好的质量和均匀性，与升华法制备的外延薄膜基本相同。利用该技术在Au(111)表面制备了一层高度有序的冠烯外延附着层，并对C60在高速振动球磨条件下的机械力化学反应制备的新型碳同素异形体C190的异构体，即富勒烯C60的三聚体进行了结构鉴定，用于首次分辨率扫描隧道显微镜成像。目前的STM技术的结果清楚地提供了直观的证据，即一个高效液相分离的馏分只由一个“环状三角形”的异构体组成，而另一个馏分则由完全不同的具有“扩展”结构的异构体组成。这些结果与理论预测符合得很好。

"Wet process" techniques, which consisted of the simple transfer of Langmuir films, were developed and investigated in order to form highly-ordered epitaxial adlayers of fullerene, their derivatives and other aromatic molecules on single crystal metal surfaces.We found that the simple transfer of Langmuir films at the air-water interface allowed us to prepare epitaxial adlayers of fullerenes on Au(111) surfaces with ambient conditions. Furthermore, the improved "wet process" method, "electrochemical replacement method" was proposed. The method consists of the transfer of Langmuir films of C_60 onto iodine-modified Au(111) surfaces at air-water interface and followed by the electrochemical removal and the replacement from iodine adlayers to C_60 adlayers in solution. The C_60 adlayers prepared by this method showed excellent quality and uniformity, and they were essentially same as epitaxial adlayers prepared by sublimation. A highly-ordered epitaxial adlayer of coronene on the Au(111) surface was also prepared by the technique.The structural identification of isomers of the novel carbon allotrope C_190, that is, the trimer of fullerene C_60, prepared by the mechanochemical reaction of C_60 under "high-speed vibration milling" conditions were demonstrated, for the first resolution STM imaging. The results of the present STM technique clearly provide the visual evidence that an HPLC-separeted fraction is composed of only an isomer with "cyclic triangular" shape while another fraction consists of totally different isomers with "extended" structures. These results are in good agreement with theoretical prediction.