Formation Of Organic Monolayers Research Articles

Organic monolayer formation at a sulphur modified gold electrode: The methylene blue/leucomethylene blue redox couple

The electrochemical formation of a condensed methylene blue (MB+)/leucomethylene blue (LMB) monolayer at the sulphur covered gold electrode (1 M aqueous electrolyte solution, pH = 7.9) is reported. The strong interaction between MB + and adsorbed sulphur in the monolayer is ascribed to a disulphide linkage between a sulphur adatom and the sulphur heteroatom of the perpendicularly oriented organic molecule. This binding also results in a change in the electrical properties of the sulphur monolayer, which increases the reversibility of the electron transfer in the first adsorbed MB monolayer. The stability of the reduced monolayer at the Au-S/aqueous electrolyte interface is affected strongly by the type of anion (F − > Cl − ⪢ NO − 3).

Vapor technique for the formation of organic monolayer tunnel junctions

A vapor technique for the formation of organic monolayers within a vacuum chamber is described. The organic dimer molecules are vaporized and then broken down into monomer molecules which chemisorb onto a fresh metal film. Subsequent layers only physically absorb and are driven off by heat, leaving a monolayer which can be used as a tunneling barrier. Details of the fabrication process and the electrical characteristics of experimental Pb-organic-Al tunnel junctions are presented.