Electrochemical properties of thiol monolayers prepared by constant-potential assembly

The monolayer of dodecanethiol was prepared on gold surface by constant-potential assembly (CPA). The properties of the monolayers were characterized using reflection absorption FT-IR, cyclic voltammetry, and electrochemistry impedance spectroscopy. Experimental results show that monolayers free from pin-hole defects can be obtained after CPA for 1 min. As the assembling time increases, the number of collapsed-site defects decreases and the packing density of the thiol monolayer increases. Compared to the monolayers prepared by self-assembly for 24 h, those obtained by CPA for 5 min have almost identical packing density and less collapsed-site defects.