One of the most promising properties of graphene is that it is a zero-overlap semimetal

(with both holes and electrons as charge carriers) with very high electrical conductivity.

Graphene is exceedingly appropriate for transistors applications due to the electron-hole

effect. Graphene is a semiconductor with zero bandgaps for the π/π^∗ bands crossing at the

Fermi level. Another fascinating property of graphene is electron mobility. Graphene is the

utmost conductive material so far at room temperature, with a conductivity of 106 S/m and

a sheet resistance of 31 Ω/sq. This is credited to its ultrahigh mobility of graphene which is

almost 140 times the mobility in silicon.

According to the refraction and interference of light, graphene with several layers

would display different colours and contrasts which can be used to distinguish the layers

of graphene. Graphene is a transparent material as it can absorb a 2.3% fraction of light.

Graphene and its associated materials spectacle brilliant mechanical properties. Graphene

is the strongest material, because of its superior mechanical properties of graphene. It is

imperative to note that mechanical properties were dependent on the purity of graphene

sheets. Thermal conductivity of graphene is contingent on the diffusive and ballistic

conditions at higher and lower temperature ranges respectively. Better thermal con­

ductivity of graphene materials is highly dependent on the quality of graphene sheets.

From a chemical reaction point of view, the pristine form of graphene is mostly not

reactive. The chemical properties of graphene are disparagingly influenced by the surface

characteristics and thickness of graphene layers. Single-layer graphene materials are highly

chemically reactive than multi-layer graphene materials. Researchers unexpectedly

found that graphene-based nanomaterials hold exceptional antibacterial properties.

Graphene oxide, graphene oxide, and reduced graphene oxide can efficiently inhibit

bacterial growth [34]. Graphene has a tremendously high specific surface area and high

porosity, making them ideal for the adsorption of different gases such as hydrogen (H2).

Graphene has the capacity of fluorescence quenching. This characteristic of graphene can be

exploited for the selective recognition of biomolecules. Graphene can be cast off as a novel

effective SERS active substrate with exceptional biocompatibility and chemical inertness.

Pristine graphene is insoluble in liquids such as water, polymer resins, and other common

solvents. Therefore, it is essential to attach certain functional groups on graphene either

physically or chemically to disperse in various common solvents without suggestively al­

tering its required properties. Functionalization of graphene can be conducted with the help

of suitable functional groups and by innovative synthetic approaches. Graphene exhibits

the property of molecular self-assembly at the liquid-liquid interface. Self-assembly of two-

dimensional graphene sheets is an imperative approach for creating macroscopic 3D gra­

phene architectures for practical applications, such as thin films and layered paper-like

materials.

16.6 Graphene-Based Bioelectronics

Graphene-based electronics offer an optimistic substitute to conventional bioelectronic

device materials to meet the challenging device requirements in biomedical applica­

tions. Sustained progress in graphene nanostructure synthesis and micro-fabrication

techniques permit innovative device architectures with tuneable physiochemical

properties. The monolithic combination of graphene permits nanoscopic field-effect

detection of chemical and biological signals with mechanically flexible and robust

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Bioelectronics