Nishino Tomoaki, Ito Takashi, Umezawa Yoshio
Department of Chemistry, School of Science, The University of Tokyo, Japan.
Anal Chem. 2002 Aug 15;74(16):4275-8. doi: 10.1021/ac020215m.
Carboxyl-terminated single-walled carbon nanotubes (SWNTs) were successfully immobilized from solution phases onto the apexes of gold tips for scanning tunneling microscopy (STM). Gold STM tips were first modified with self-assembled monolayers of 4-mercaptobenzoic acid, and its carboxyl groups were used to anchor carboxylated SWNTs through Zn2+ ion-bridged coordination. These SWNT tips gave high-resolution STM images of a diether monolayer formed on the graphite surface. In addition and more importantly, the ether oxygens of the sample molecules were selectively observed as bright spots with the SWNT tips with significantly high reproducibility, which is due to the facilitation of electron tunneling through hydrogen bond interactions between the ether oxygens and carboxyl groups at the end of the SWNT tips.
羧基封端的单壁碳纳米管（SWNTs）成功地从溶液相中固定到用于扫描隧道显微镜（STM）的金尖端顶端。金STM尖端首先用4-巯基苯甲酸的自组装单分子层进行修饰，其羧基通过Zn2+离子桥联配位用于锚定羧化的SWNTs。这些SWNT尖端给出了在石墨表面形成的二醚单分子层的高分辨率STM图像。此外，更重要的是，样品分子的醚氧以亮点形式被SWNT尖端选择性地观察到，具有显著高的重现性，这是由于醚氧与SWNT尖端末端的羧基之间通过氢键相互作用促进了电子隧穿。
