Self-Assembly of π-Conjugated Azomethine Oligomers by Sequential Deposition of Monomers from Solution

Abstract

A novel technique for the controlled fabrication of π-conjugated oligomers bonded to a substrate is presented. On a gold substrate, monolayers of small monomeric organic units are alternately deposited from solution. They order and connect to the previous layer by self-assembly. In each deposition step, chemisorption takes place on top of the previous monolayer through a condensation reaction. The oligomer chain growth has been analyzed by scanning tunneling microscopy, ellipsometry, and X-ray photoelectron spectroscopy. The azomethine molecules order approximately perpendicular to the gold surface. This growth process allows for flexible preparation of a range of oligomers in a self-assembled monolayer with variable electronic properties.