Substrate-molecule decoupling induced by self-assembly—Implications for graphene nanoribbon fabrication

Interactions between organic molecules and metal surfaces are often very strong, resulting in the loss of well-defined frontier orbitals on the molecule due to electronic hybridization with the surface. In this paper, we use theoretical calculations to show that the interaction between graphene nanoribbon precursor molecules and copper surfaces is weakened upon molecular self-assembly. This phenomenon, which we abbreviate as SAID (Self-Assembly Induced Decoupling), increases the adsorption distance of the molecules to the surface, and results in a partial recovery of frontier molecular orbital electron density. The SAID phenomenon opens a new topic in the field of organic-metal interface physics, and may have broader implications for thin film devices and catalysis.