**2. Introduction of graphene**

There are some well-known nanosheet materials with strong bonding on surface and poor bonding between layers such as graphene, BNNSs, and MX2. Due to their specific structures, researchers have made great efforts to produce 2D nanosheets by exfoliating these layered compounds into distinct layers. A transmission electron microscopy image of crumpled monolayer of graphene is shown in **Figure 2**.

Graphene is the most famous of 2D nanosheets that is composed of carbon atoms in a hexagonal (honeycomb) configuration with sp2 -hybridized atoms

**23**

**Figure 3.**

*Different forms of graphitic carbon [13].*

*Two-Dimensional Nanomaterials*

material (3D) (**Figure 3**) [12].

**2.1 The synthesis of graphene**

**2.2 Graphene properties**

conduction.

*DOI: http://dx.doi.org/10.5772/intechopen.85263*

[10, 11]. Graphene is also the most important member of the multidimensional carbon material family that is formed by putting together carbon atoms and which included fullerene as the zero-dimensional nanomaterial (0D), carbon nanotubes as a one-dimensional nanomaterial (1D), and graphite as a three-dimensional nano-

Graphene has a very weak absorption coefficient of 2.3% of white light, and

discovery of this compound in 2004 attracted a lot of attention and led to the discovery of great electronic properties, electron transfer capabilities, unprecedented impermeability, and high mechanical strength, excellent thermal, and electrical

Single-layer graphene is a substructure for the construction of carbon structures, which if placed on each other, produce 3D graphite. The attractive force between layers is van der Waals (vdW) force with a gap of 0.335 nm [14]. If singlelayer graphene is rotated around the axis of the tube, the 1D carbon nanotube, and

The numerous chemical and physical methods have been proposed for the production of different types of graphene (from single layer to few layer) based on top-down and bottom-up approaches. Chemical vapor deposition (CVD) and epitaxial growth [15, 16], plasma-enhanced chemical vapor deposition (PECVD) [15], mechanical cleavage [14, 17], Scotch® tape technique [17], chemical synthesis [18], liquid exfoliation [19, 20], etc. have been widely used to produce graphene.

Considering the attention of scientists to graphene and the hope for its various applications in the near future, many research efforts have been devoted to understanding the structure and properties of graphene. Graphene is expected to

/gr, which is

/gr. The legendary

so it's seen as a white powder. The surface area of graphene is 2630 m<sup>2</sup>

twice as much as carbon nanotubes with a surface area of 1315 m<sup>2</sup>

if they are wrapped spherically, it forms the 0D fullerene.

**Figure 2.** *The transmission electron microscope image of a crumpled graphene [9].*

*Two-Dimensional Nanomaterials DOI: http://dx.doi.org/10.5772/intechopen.85263*

*Nanostructures*

clarified.

**Figure 1.**

**2. Introduction of graphene**

different. In graphene, each carbon atom is next to another carbon atom in its upper and lower layers, while in the structure of BNNSs, each atom is located in the center of the benzene ring on the upper and lower layers. In the structure of dichalcogenides, each atomic layer of metal is sandwiched between two atomic layers of X. In this chapter, the recent developments in the synthesis, properties of 2D nanomaterials especially graphene, and boron nitride nanosheets (BNNSs) are discussed. A comprehensive understanding of the properties and physics of these materials can be very effective in finding their application in the industry that is discussed in this chapter. The reported virtues and novelties of these nanomaterials are highlighted, and the current problems in their developing process are

*The structure of (a) single layer of graphene with a lattice of carbon atoms, (b) boron nitride nanosheets with* 

*B in blue and N in pink, and (c) tungsten diselenide (WSe2) with W in blue and Se in yellow [8].*

There are some well-known nanosheet materials with strong bonding on surface and poor bonding between layers such as graphene, BNNSs, and MX2. Due to their specific structures, researchers have made great efforts to produce 2D nanosheets by exfoliating these layered compounds into distinct layers. A transmission electron


microscopy image of crumpled monolayer of graphene is shown in **Figure 2**. Graphene is the most famous of 2D nanosheets that is composed of carbon

atoms in a hexagonal (honeycomb) configuration with sp2

*The transmission electron microscope image of a crumpled graphene [9].*

**22**

**Figure 2.**

[10, 11]. Graphene is also the most important member of the multidimensional carbon material family that is formed by putting together carbon atoms and which included fullerene as the zero-dimensional nanomaterial (0D), carbon nanotubes as a one-dimensional nanomaterial (1D), and graphite as a three-dimensional nanomaterial (3D) (**Figure 3**) [12].

Graphene has a very weak absorption coefficient of 2.3% of white light, and so it's seen as a white powder. The surface area of graphene is 2630 m<sup>2</sup> /gr, which is twice as much as carbon nanotubes with a surface area of 1315 m<sup>2</sup> /gr. The legendary discovery of this compound in 2004 attracted a lot of attention and led to the discovery of great electronic properties, electron transfer capabilities, unprecedented impermeability, and high mechanical strength, excellent thermal, and electrical conduction.

Single-layer graphene is a substructure for the construction of carbon structures, which if placed on each other, produce 3D graphite. The attractive force between layers is van der Waals (vdW) force with a gap of 0.335 nm [14]. If singlelayer graphene is rotated around the axis of the tube, the 1D carbon nanotube, and if they are wrapped spherically, it forms the 0D fullerene.
