Structure of graphene and its disorders: a review

Abstract

Monolayer graphene exhibits extraordinary properties owing to the unique, regular arrangement of atoms in it. However, graphene is usually modified for specific applications, which introduces disorder. This article presents details of graphene structure, including sp2 hybridization, critical parameters of the unit cell, formation of σ and π bonds, electronic band structure, edge orientations, and the number and stacking order of graphene layers. We also discuss topics related to the creation and configuration of disorders in graphene, such as corrugations, topological defects, vacancies, adatoms and sp3-defects. The effects of these disorders on the electrical, thermal, chemical and mechanical properties of graphene are analyzed subsequently. Finally, we review previous work on the modulation of structural defects in graphene for specific applications.

Extrusion of Polymer Nanocomposites with Graphene and Graphene Derivative Nanofillers: An Overview of Recent Developments

“…The carbon atoms are bound by means of two single and one double covalent bond to the three adjoining atoms [32,33]. The graphitic structure consists in multi-layered graphene sheets, and it is considered that G can be found in different arrangements, such as: graphene monolayers, graphene nanosheets and graphene nanoplatelets (GnPs) [34,35]. This nanomaterial exhibits remarkable attributes such as mechanical, electrical and thermal properties, among others, which are summarized in Table 1 [36][37][38].…”

Failure in Two-Dimensional Materials: Defect Sensitivity and Failure Criteria

“…Chemical functionalization is one of the main tools applied to examine the mechanisms of interaction of 2D materials with their environment [65]. Different chemical groups (hydrogen, chlorine, fluorine, and oxygen [52]) can be attached to 2D materials (see Fig. 3(c)) to modify their structures and properties [66].…”

“…Note that double vacancies with an even number of missing atoms allow the complete saturation of dangling bonds, and therefore, they are thermodynamically favored over [34,47,54,61,74,88,89,92,[107][108][109]. single vacancy or triple vacancies with an odd number of missing atoms [52]. Subsequently, the atomic structure around the created vacancy is relaxed through geometry optimization.…”

Graphenic Materials for Biomedical Applications

“…According to Wick et al [35], a few-layer GR is composed of 2-10 GR layers composed of flake-like stacks, while ultrathin graphite consists of more than 10 layers, where the thickness is below 100 nm. This should be applied also for GO [15,35,36]. The interactions of GO flakes are strongly influenced by their size.…”

“…TEM or Raman spectroscopy and AFM allow the determination of the number of layers and lateral dimensions. An accurate and real view of sheet quality, the number of defects, and delamination achieved can be obtained from AFM, which allows the determination of lateral dimensions by analyzing the shape and height of the GR/GO flakes [15,36,[41][42][43].…”