Electrostatic-Interaction-Induced Molecular Deposition of a Hybrid Bilayer on Au(111): A Scanning Tunneling Microscopy Study

Hybrid bilayers consisting of 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and meso-tetra(4-pyridyl)porphine (TPyP) have been successfully constructed on Au(111) and investigated by electrochemical scanning tunneling microscopy (ECSTM). Under the guidance of the electrostatic interaction between negatively charged sulfonate groups and positively charged pyridyl groups, the underlying HPTS arrays act as templates for the deposition of cationic TPyPs, forming two types of TPyP/HPTS complex bilayers. The present work provides a feasible way to fabricate hybrid multilayers on the electrode surface via electrostatic interaction, which has great significance for the design of molecular nano devices.