Iodine-Induced Self-Assembly Structure Transition of Organic Molecules on the Ag(111) Surface

Abstract

Iodine adsorption on metal surfaces has been extensively studied, but iodine’s effect on modulating the self-assembly structures of organic molecules has been less discussed. Here, we used low-temperature scanning tunneling microscopy and density functional theory to systematically study the self-assembly structure transformation of organic molecules affected by iodine dosing on the Ag(111) surface. We chose 2,6-naphthalenedicarboxylic acid and persilylated hexaethynylbenzene molecules and their reaction products as models to explore the changes in the molecular self-assembly structures on the Ag(111) surface induced by iodine deposition. Some new self-assembly structures are obtained by depositing iodine onto the molecules’ co-covered surface at different stages. These findings show that iodine can modulate the self-assembly structure of organic molecules with a weak intermolecular interaction, while those with a stronger intermolecular hydrogen bonding are not affected. The trend is verified with the density functional theory calculations.