Preparation, Bandgap Engineering, and Performance Control of Graphene Nanoribbons

Abstract

Graphene nanoribbons (GNRs) exhibit a series of essential electronic properties, especially in establishing tunable bandgaps. The bandgaps are determined by structural features of GNRs, including orientation, width, backbone/edge structure, heteroatom doping, and overall quality. These parameters affect the electronic properties of the GNRs to a large extent. To better incorporate GNRs into nanoscale electronic devices, obtaining high-quality GNRs with precisely defined bandgaps is a significant necessity. To date, different preparation techniques have offered a vast range of available materials for fabricating GNRs, where hydrocarbon gases and halogen-containing aromatic molecular precursors are the most important candidates. Therefore, it is fundamental to categorize the existing techniques in preparation, bandgap modulation, application of GNRs, and obtaining systematic knowledge on how to take advantage of this frontier material. Herein, overall understandings on the synthesis strategies and bandgap engineering tactics related to GNRs are presented in detail. Various techniques of top-down approaches and bottom-up syntheses, the origin of GNRs’ bandgap from quantum confinement effect, a diversity of bandgap engineering tools, and the applications of GNR-based devices are comprehensively reviewed with critical comparisons. In addition, the remaining challenges and promising opportunities are listed to catalyze upcoming findings pushing forward the ultimate applications of GNRs.

Carbon Graphitization: Towards Greener Alternatives to Develop Nanomaterials for Targeted Drug Delivery

“…Nanohorns (CNHs) consist of clusters of nanocones [ 22 ], while nanodots (CNDs) have been attracting increasing attention, thanks to their ultra-small size (<10 nm) and luminescence [ 23 ]. Graphene nanoribbons (GNRs) display yet another morphology, as the name suggests, and they are highly researched for the possibility they offer to fine-tune their electronic properties and, in particular, the bandgap through the modulation of structural features, such as width, orientation, backbone and edge structure, heteroatom doping, and, in general, their quality [ 24 ].…”

Topological Impact of Delocalization on the Stability and Band Gap of Partially Oxidized Graphene

“…Since hexagonal geometry is ideally suited for sp 2 -hybridized carbon, atomistically thin graphene, with its semimetallic hexagonal network and high thermodynamic stability, conceptually provides an ideal canvas for design strategies to engineer the band gap. , Synthesizing a tunable band gap in semimetallic graphene requires prudent control of π-electron delocalization. Approaches based on quantum interference and confinement lead to the development of nanoribbons, nanodots, nanoflakes, nanomesh, etc. Though these open the band gap, they suffer from the excessive sensitivity of frontier bands by the nature of truncated edges.…”

“… 10 , 11 Synthesizing a tunable band gap in semimetallic graphene requires prudent control of π-electron delocalization. Approaches based on quantum interference 12 and confinement 13 lead to the development of nanoribbons, nanodots, nanoflakes, nanomesh, etc. Though these open the band gap, they suffer from the excessive sensitivity of frontier bands by the nature of truncated edges.…”

Topological Impact of Delocalization on the Stability and Bandgap of Partially Oxidized Graphene

“…Tuning the bandgap in semimetallic graphene requires prudent control of π-electron delocalization. Approaches based on quantum interference 12 and confinement 13 lead to the development of nanoribbons, nanodots, nanoflakes, nanomesh, etc. Though these open the band gap, they suffer from the excessive sensitivity of frontier bands by the nature of truncated edges.…”