Electron transport of single redox molecular junctions has been studied by the STM break junction technique under electrochemical conditions. The target molecules were perylene tetracarboxylic acid bismides modified with pyridine and methylthiol linker groups with bulky tert-butylphenoxy substitutents in the bay area. The conductance of the single molecular junctions can be tuned up to two orders of magnitude by varying the electrochemical "gate" potential, showing a transistor-like behavior. In addition, the tunneling current between a bare Au STM tip and redox molecules modified Au(111) electrode in aqueous electrolyte was strongly enhanced, which was attributed to a sequential two-step electron transfer process.

This work was carried out in the group of Prof. Thomas Wandlowski.

References:

• C. Li, A. Mishchenko, Z. Li, I. Pobelov, Th. Wandlowski, X. Q. Li, F. Würthner, A. Bagrets, F. Evers;
  "Electrochemical gate-controlled electron transport of redox-active single perylene bisimide molecular junctions"
  J. Phys.: Condens. Matter, 20, 374122, (2008); doi:10.1088/0953-8984/20/37/374122.