Computational study of bottom-up fabrication of armchair graphene nanoribbons

Graphene nanoribbons have promising electronic properties for nanotechnology. They can be fabricated using a bottom-up procedure with specific molecular precursors, which results in atomically precise nanoribbon structures. Herein we demonstrate the formation of a 7-atomic-layer pristine armchair graphene nanoribbon from the 10,10'-dibromo-9,9'-bianthracene precursor through polymerization followed by cyclodehydrogenation. We performed calculations using density functional theory with van der Waals corrections to study how Au(111) and Cu(111) substrates affect the energy profiles for the reaction process. To further understand the effects of the substrate on the cyclodehydrogenation procedure, we also considered double-layer ribbon structure on top of the substrate. These results may provide insight into the use of different precursors for producing both polymers and ribbons with novel electronic properties.