Study on the Self-Assembly Process of 2,7-Dibromopyrene Molecules

Abstract

The first-principle technique has been utilized to investigate the self-assembly process of 2,7-dibromopyrene (Br2Py) molecules in forming monolayers. Based on Br-H adsorption and Br-Br repulsion, Br2Py molecules form two molecular chains and one molecular cluster, which then lead to the formation of four possible monolayers. CASTEP calculation demonstrates that both the molecular chains and monolayers are all the self-assembly system, with the structural parameters of the monolayers being consistent with existing literature. Electron density analysis has been conducted on these molecular chains and monolayers to validate the Br-H adsorption and Br-Br repulsion. Furthermore, a proposed probability for occurrence of monolayers is presented. It is evident that while the atomic structure of a Br2Py monolayer is primarily influenced by intermolecular interactions, there exists a certain selectivity for film-forming on metal surfaces.

Keywords: Molecular self-assembly, Br2Py monolayer, First-principle theory, CASTEP, Electron density