A Study on the Electrochemical and Structural Properties of a Schiff Base SAM on Au(111)Surface

摘要

The electrochemical and structural properties of Schiff ase V-hp self-assembled monolayer(SAM)on Au(111)surface have been studied using electrochemical technique and electrochemical scanning tunneling microscopy(ECSTM)in 0.1 M HClO4 solution.C_yclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)measurements revealed that the adlayer of V-hp on Au(111)surface inhibits the oxidization of Au and reduces the surface double-layer capacitance.The electronic charges for V-hp-SAM covered Au(111)electrode,resulting from capacitive charging and discharging process involved in the double-layer potential region,become one or more orders of magnitude lower than that for bare Au(111).STM investigation demonstrated that V-hp molecules can adsorb with a flat-lying orientation on Au(111)and formed a long-range two-dimensional ordered SAM with a(2 3~(1/2)X21~(1/2))adlattice symmetry structure.A model structure with one molecule per unit cell was proposed,which yields a surface concentration of 1.28Xl0~(-10)mol/cm2.