Making graphene nanoribbons: a theoretical exploration

Abstract

Graphene nanoribbons (GNRs), thin and long strips of single carbon layer, exhibit very charming electronic and magnetic properties, and show great promising applications in electronics and optoelectronics devices. Therefore, reliable and efficient techniques of making high-quality GNRs have attracted enormous interests in recent years. Numerous methods of making GNRs, including both top-down and bottom-up schemes, have been developed, and among them, metal-catalyzed and oxidative cutting of graphene and/or carbon nanotube as two most promising approaches have been widely used to fabricate GNRs with different widths, edges, and defects. However, precise control of mass production of narrow GNRs with well-defined and smooth edges is still very challenging. To reach this goal, it is essential to well understand the underlying mechanisms of making GNRs in different conditions, such as the force that drives the cutting process, catalyst, and agent-dependent cutting behavior, orientation-selective cutting at the atomic level. Recently, theoretical investigations based on quantum chemical calculations have made great progress in this area.

The Nanoparticle Size Effect in Graphene Cutting: A “Pac‐Man” Mechanism

“…[14] To better control the cutting process,t he underlying atomic mechanisms should be understood. [21][22][23][24] Currently,the unzipping mechanism [7,[25][26][27] is the dominant graphene-cutting mechanism reported in the literature,w here C À Cb onds in graphene are broken by single cutting atoms and the nanoparticle size is thus irrelevant. However,s ignificant nanoparticle size effects on both the cutting behavior and the resulting graphene edge morphology have been observed experimentally.…”

“…To compare with the unzipping mechanism, [7,[25][26][27] we also construct models with only one Ni atom included. At the …”

The Nanoparticle Size Effect in Graphene Cutting: A “Pac‐Man” Mechanism

“…[14] To better control the cutting process, the underlying atomic mechanisms should be understood. [21][22][23][24] Currently, the unzipping mechanism [7,[25][26][27] is the dominant graphene-cutting mechanism reported in the literature, where C À C bonds in graphene are broken by single cutting atoms and the nanoparticle size is thus irrelevant. However, significant nanoparticle size effects on both the cutting behavior and the resulting graphene edge morphology have been observed experimentally.…”

“…To compare with the unzipping mechanism, [7,[25][26][27] we also construct models with only one Ni atom included. At the zigzag edge, one Ni atom requires 1.93 eV to break the edge C À C bond.…”

Trapped modes in zigzag graphene nanoribbons

“…The main purpose of those studies is to eliminate disorder completely and produce pure high-quality graphene nanoribbons [7]. As we are approaching the goal of graphene nanoribbons free of impurities and other defects, we can focus on the design of disorder for the use in electronic devices.…”