Work Function Changes of Azo-Derivatives Adsorbed on a Gold Surface

By employing state-of-the-art computational techniques, we investigate two self-assembled monolayers (SAMs), constituted by azobenzene derivatives chemisorbed on a gold surface (azo-SAMs). We study the structural features and the work function change of the azo-SAMs as a function of the conformation of the molecules (trans or cis), of the unit cell sizes, and of the anchoring site (bridge, hollow, on-top). The data obtained by the theoretical calculations are compared with both experimental and computational data of literature. Concerning the work function change due to the azo-derivative photoisomerization, the results are in agreement with the experimental data, and are qualitatively robust with respect to the structure of the SAM.