![]() Graphene is treated nowadays as a rising new material in the field of high-efficiency sensors, fuel cells, renewable energy sources, transparent electrodes, and nanocomposite materials. One single-layer of graphene has a transparency of 97.7% of incident light and absorbs only 2.3% and, it is almost completely transparent. Thus, graphene is a promising material for high-performance nanoelectronics, heat dissipation, sensors, field emission, and transparent conductor. It is estimated that graphene is 100 times stronger than the best steel ever for the same thickness. Thus, graphene is the strongest material ever discovered to date. Graphene is the strongest material ever measured and has excellent mechanical properties with an elastic modulus of 1 TPa and ultimate tensile strength of 130 GPa. The unique structure enables graphene of many distinctive properties and promising applications. Graphene has a high specific surface area of 2630 m 2/g. Graphene has high mobility of charge carriers (200000 cm 2/V.S), which means an electron moves through it without much scattering or resistance. A Single-layer of graphene has thermal conductivity as high as 5000 W/m.K and higher about 10 times than Cu and superior to carbon nanotubes (CNTs) and diamond. ![]() These nanomaterials have many medical applications, integrated circuits, transparent conducting electrodes, desalination, solar cells, energy storage, biodevices, etc.ĭue to its unique thermal, electrical, and mechanical characteristics, Graphene has been utilized in many applications. Graphenes can exist in different forms: graphene oxide, chemically modified graphenes, bilayer graphenes, etc. The other bond is between carbon-carbon atoms with 0.142 nm spacing, which is a strong covalent bond entire each layer. This weak attraction between layers can ease the exfoliation into individual layers. The graphene layers are held together by the weak Vander Waal attraction with a length of about 0.341nm between the adjacent graphene layers. There are two kinds of bonds form among the graphene layers. Graphite is considered to consist of huge numbers of graphene layers. ![]() Moreover, it is the thinnest and strongest material that is ever subjected to measurement. ĭue to the outstanding features and large applications, Graphene has attracted great interest from scientists and engineers. Graphene is a flat single atom thick sheet of carbon packed into a honeycomb crystal plane and has a 2D structure. ![]() Carbon nanotubes are either single-walled CNTs (SWNT) or multiwalled CNTs (MWNT). Carbon nanotubes (CNTs) are one dimension structure that can be viewed as a hollow cylinder formed by rolling a two-dimensional graphene sheet into a cylinder with a half fullerene at its ends. The most widely publicized fullerene is buckyball (C60). Fullerenes are zero-dimensional hollow carbon cage structures with carbon atoms arranged in a lattice similar to the soccer-ball. In diamond, the carbon atoms are arranged in a face-centered cubic crystal structure (FCC) system with diamond lattice. The interplanar spacing, d, is (0.335nm). Graphite has a layered planar structure wherein each carbon atoms layer is arranged in a honeycomb lattice with a separation of 0.142 nm. ĭiamond, graphite, graphene, C60 (Buckminsterfullerene), carbon nanotube, and amorphous carbon are graphical examples of carbon allotropes. Graphene has been considered as the fundamental building block for all sp 2 graphitic materials, including (0D) fullerenes, (1D) carbon nanotubes, and stacked into (3D) graphite. Graphene is a 2-dimensional structure consists of a single atom thick sheet of carbon crystallized as a honeycomb structure monolayer. While in 2004, graphene, which is a two-dimensional form of graphite, was isolated at Manchester University by Novoselov et al. Iijima, in 1991, discovered carbon nanotube (CNT). marked the beginning of an era of synthetic carbon allotropes with striking properties. In 1985, the discovery of fullerenes by Kroto et al. Īllotropes are elements that are chemically identical but vary in their physical properties. Diamond and graphite consist of extended networks of sp 3- and sp 2 -hybridized carbon atoms, respectively. For example, graphite is soft and black, and stable, while diamond is hard and transparent. The atomic arrangement of carbon atoms in these materials gives different properties. It is known that graphite and diamond are the two natural crystalline allotropic forms of carbon for a prolonged time.
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