Multiscale simulation of surface-assisted synthesis of 7-armchair graphene nanoribbons

Abstract

The on-surface synthesis method is a remarkably promising technology in producing nanometer-wide graphene nanoribbons (GNRs) whose edge structures are well preserved. Controlling the quality of GNRs in terms of length is important for various GNR-based applications. We studied the surface-assisted synthesis of 7-armchair graphene nanoribbons (7-AGNRs) using a multiscale simulation method combining ab initio molecular dynamics simulations (AIMD) and kinetic Monte Carlo (KMC) simulations. The effect of monomer coverage and substrate type on the polymerization process are investigated. The length of the synthesized polyanthracene/GNRs on both Au(111) and Ag(111) substrates is shown to be significantly influenced by the deposited monomer amount. Ag(111) is better than Au(111) in facilitating the formation of longer polyanthracene/GNRs. An empirical mathematical model for predicting the percentage of long GNRs in the growth process is developed based on reaction parameters such as monomer coverage, the bonding and diffusion activation energies of DBBA radicals on the substrate, and temperature. This work provides a robust means for predicting and controlling the synthesis of 7-AGNRs on various substrates and presents a general multiscale framework for the synthesis of various GNRs.