The World Is Now Under the Innovation of the Mystery Material “Graphene”!

Graphene was first known to our technological world when Andre Geim’s and Konstantin Novoselov’s discoveries on its quantum properties acclaimed the 2010 Nobel Prize in Physics. It was discovered in 2003 by removing a single layer of carbon lattice from graphite. Since then its applications was fetched out in different fields, proving to be a highly promising allotrope of Carbon. The discovery of Graphene has given a new dimension to material science, research and development.

Graphene often known by its superlative, “The World thinnest and strongest material ever found on Earth”, it is the best conductor of heat and electricity, its charge carriers exhibit giant intrinsic mobility and have the least effective mass, that travels micrometer long distances without scattering at room temperature and hence its properties goes on and on.?

Graphene is a defect-free, single layer of Carbon atoms arranged in a hexagonal lattice. Graphene was first used in the manufacture of graphite using pyrolysis; literally, layers of graphene when sandwiched together by feeble bonds form the Graphite molecule. In 1994, the “graph” of Graphite is suffixed with “-ene” which most polycyclic hydrocarbons use, to form the word Graphene as per the recommendations from IUPAC.

The Structure of Graphene is as shown below, with a layer of independent s?hybrid carbon atoms. There are 4 valence electrons per carbon atom, including 3 electrons (2s electrons, 2px??electron and 2py electron) forming plane sp2 hybrid orbitals. Each Carbon atom makes 3σ-bonds, that is each carbon atom in graphene is bonded to three adjacent carbon atoms through a σ bond and 1π-bond, which is formed by the remaining p electron with the surrounding atoms and the bonding direction is perpendicular to the graphene plane. σBonds are responsible for the mechanical properties of graphene and π bond is responsible for the electrical characteristics. Graphene is considered to be the hardest material on Earth, stronger than diamond because the σ bonds in its lattice are very strong since the in-plane bond length is smaller than that of the diamond.?

Graphene is the most stretchable crystal, thinnest, highly transparent and the most impermeable material ever discovered. A single layer of graphene has approximately 80% high optical transparency. It is considered to be the strongest material, over 200 times stronger than steel. Graphene has a thermal conductivity ten times higher than that of Copper. It has an intrinsic electron mobility of a hundred times that of Silicon.

Graphene and graphene oxide have excellent electrical, mechanical and thermal properties due to unique structure and morphology. Graphene exhibit Hall effect and hence they are used for Magnetic field sensing equipment, proximity sensors, wheel speed detectors and used to assist anti-lock braking system.

What is Hall Effect? 
When a current carrying conductor or semiconductor is introduced to a perpendicular magnetic field, then a voltage can be measured at right angle to the current path.        

Similarly, graphene exhibits tunneling effect by which its applications can be found in tunneling diode, quantum computing and in the scanning tunneling microscope. Tunneling plays an important role in nuclear fission and radioactive decay of atomic nuclei where a particles are emitted.

The advantages of two-dimensional Graphene over semiconductors such a silicon used in Field Effect Transistors FETs are many. In standards FETs the semiconductor sensors are three-dimensional and moreover electric current changes at the surface of the channel need not pass deep into the device always, in-fact they do pass but we can’t avoid situations where it shall not penetrate into it. So, the application of graphene into FETs, more clearly GFETs has graphene over semiconductors which is two-dimensional and only one atom thick. The entire channel will be on the surface itself that can dramatically increase the response sensitivity of the device. Existing silicon conductors when brought into atomic size shall be inefficient since surface defects and dangling bonds dominate over the ideal semiconductor features. GFETs have higher carrier mobility than standard FETs, often levels higher than 105 cm2 (Vs)?1 .

Graphene can be utilized to increase the strength of any material that can benefit us. Even a trace of it can make any material stronger and even lighter, when entirely depends on our demand. Graphene thus has the potential to rejigger the entire industries. Its latest research has found out developments in different fields ranging from health to aerospace. The thermal conductivity of Graphene is extremely high, approximately 4000 Wm?1 K?1. Adding to it, Graphene’s high Seebeck coefficient make it easier to convert electric current to heat. Moreover, graphene dominates over other properties such as Youngs Modulus, the modulus of elasticity in tension or compression and its Young’s modulus ranges to 1100 GPa. Graphene transmits about 97.9 % of visible light through it.

Graphene is a rising star on the horizons of material science and condensed matter physics with its potential application. Graphene is currently being used for anything from solar cells to water filtration systems to touch screens. The ambipolar electric field effect in single layer graphene exhibit its characteristics where the charge carriers have high mobility when compared to that of semiconductors. Graphene can be used widely in energy harvesting purposes since its thermoelectric power is considerably high. The steadfast increase in the production of graphene derivatives such as graphene oxides GO, reduced graphene oxides rGO, and graphene composites has opened up an arena of possibilities to synthesize graphene based functional materials for various applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis and so on.

In photocatalytic fields, the technology deals with the semiconductors, excited by light with an energy higher than that of its band gap, several two-dimensional graphene nanosheets supported semiconductors are used for creation of materials with relatively high aspect ratios, high surface areas, lower densities in different fields like Solar manufacturing, thermal catalysis, separation, purification and so on, due to its unique electrical, optical & physiochemical properties, its higher surface area, charge transfer and adsorption capability.

Graphene being a semimetal with zero bandgap, it shall not be used for field effect transistors. Graphene if processed to nanoribbons with a thickness less than 10nm can have a bandgap large enough for an effective transistor operation at room temperature. Since graphene Nano ribbons possess low driving currents and their application in practical devices and circuits will require thick arrays of ordered nanoribbons, Graphene Nano mesh having neck width less than 5nm can be utilised for field-effect transistors that can support current hundred times greater than that of graphene ribbons.

At present, burning fossil fuels contributes much to the pollution we are facing now complementing the Global warming resulting Climatic Changes. Though CO? produced due to the burning of such fuels are released in huge quantities day by day, a solution to this problem can be implementing the Carbon Capture method to cut down the CO?. It is a chemical technique that prevents CO??from post combustion emissions entering the atmosphere. By using high performance membranes which acts as polymer filters separates CO??from the gaseous mixture, such as those expelled out of Industries. These membranes based on graphene has size thinner than 20nm, are environmentally friendly and it is considered to be one of the efficient ways of controlling CO??emissions.

The power of graphene can be harnessed when it is used as an additive enhancing the properties of existing products. Because of its enhanced compatibility, graphene nanoplates, sheets and oxides are experimented to best suit the purpose of fillers in organic polymers. Coating can be defined as a shield applied to the substrate or as a substance spread over the substrate improving the surface properties such as adhesion, corrosion resistance, wettability, etc. and thereby providing protection to the substrate. A Coating consists mainly of two major components, namely pigmentation and vehicle. Pigmentation Corrosion resistance is enabled via a mechanism called barrier protection, where in this physiochemical reaction graphene in the coatings creates an impervious overlay that ward off air, moisture and salt coming in contact with the substrate underneath. Hence preventing electrochemical reactions that instigate corrosion.

Coating Industries have now utilised graphene due to its superior strength and substrate adhesion, excellent overcoatability, negligible weight and reduced maintenance costs. Since graphene added coatings has multifunctional properties such as increased durability, conductivity, chemical & corrosion resistance and so on, it is considered to be the highly acclaimed and desired coating additive. Graphene coated sand is now tried in the construction industry since it increases the mechanical strength improving the performance of cement composites. Graphene oxides significantly improves the mechanical performances such as durability, strength, toughness and electrical conductivity. But the non-uniform distribution of graphene oxides in the cement mixture doesn’t produce the desired result. Hence graphene uniformly coated sand composites which annealed to reduce GO to rGO to ensure it high quality. This has proved out to be novel approach towards developing performance-oriented cement-based composites.

Ultracapacitors based on EDLC – Electrochemical Double Layer Capacitance are electrical storage devices that have high energy density compared to that of conventional dielectric capacitors. They stock large amount of charge which is delivered at higher power ratings than rechargeable batteries. Ultracapacitors have many Chemically Modified Graphene CMG having good electrical conductivity and large surface area is highly efficient raw material for EDLC Ultracapacitors. Research has proved their use to be compatible with existing electrolyte systems. CMG’s are based on abundantly available and cost-effective graphite which would further lead to their large-scale adoption in storage applications.

Recently, Super porous nanosponges, a new composite material embedded in graphene sheets have turned out to be an efficient filter system to remove organic pollutants from water. These composite materials are called Covalent Organic Frameworks (COFs). COFs are extremely porous, able to cover a massive surface area and are effective at seizing large molecules, further filtering out pollutants such as organic dyes, toxic industrial wastes and so on. COFs when first used in their powdered form were incompetent. So, researchers found an effective way of spreading out two-nanometer thick COFs over graphene sheets of single atom thickness. Graphene itself being porous allows any filtrate to pass through it, thereby allowing COFs to carry out their task.

Furthermore, Hydrogen is the most clean, nontoxic fuel available and the most convenient solution for the existing traumas in energy conservation and environmental issues. The energy produced through Hydrogen is the only replacement to fossil fuels which we are still consuming in this age of Energy and Fuel crisis. The Switch to Hydrogen Energy has become the need of the hour since the current scenario demands such a change that shall be cost effective, clean production and also safe storage. Hydrogen can be produced through photocatalysis where graphene is used as the photocatalyst and it is used as an adsorber in hydrogen storage applications because of their porous and high surface area.??

To Sum up, Graphene’s physiochemical properties are unexceptional when compared to that of metals and semiconductors. Despite of that fact that Graphene technology has influenced every sector in the field of electronics, the development and manufacture of materials for commercial electronics still remain as a hard nut to crack. Further through research and analysis, we can hope such challenges shall be resolved making graphene a much-demanded raw material for the future electronics age.