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

Iodine adsorption on metal surfaces has been extensively studied, but iodine's effect on modulating the selfassembly 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.