Electrochemically controlled microstructure based on self-assembled thin film of (3-mercaptopropyl) trimethoxysilane at gold electrodes and STM characterization

The interface microstructure, based on the (3-mercaptopropyl) trimethoxysilane (MPS) self-assembling thin film, can be controlled by electrochemistry at the gold electrode. The size, number and chemical characteristics of the defect sites (or imperfections) can be reproduced. The electrochemically produced defect sizes of MPS thin films at the gold electrode were characterized by scanning tunneling microscopy (STM) and calculated based on the change of electron transfer kinetics. The size of the defects ranged from 15 Å to 200 Å in diameter. The modified surfaces have been used as a molecular recognition device, even for the same molecules with different oxidation states. The MPS thin film, with nanometer defects, has a potential of use in the study of single molecule electrochemistry.