Know about Graphene

What is graphene?

Graphene is the world’s first 2D material. Graphene is a two-dimensional honeycomb arrangement of carbon atoms that is revolutionizing technology. The word “graphene” refers to a single-layer sheet of hexagonally-arranged carbon atoms.

Graphene is made of a single layer of carbon atoms that are bonded together in a repeating pattern of hexagons. A nanomaterial is one whose size dimensions are less than 100 nanometers.Graphene-based materials are of great interest for Nanoscience and Nanotechnology, mainly for Nanoelectronics.

It was first studied in Manchester in 1947. The term graphene first appeared in 1987 to describe single sheets of graphite as a constituent of graphite intercalation compounds (GICs), conceptually a GIC is a crystalline salt of the intercalant and graphene.The first samples of graphene were made using sticky tape.The word “graphene” is sometimes used interchangeably with the term “carbon nanotubes” or CNTs.

Graphene properties:

  • It is one million times thinner than paper.
  • It is one million times smaller than the diameter of a single human hair.
  • It is 200 times stronger than steel, but it is incredibly flexible.
  • It has no band gap. It helps to produce transistors.
  • It is better than silver at conducting.
  • It is 100 times lighter than aluminum.
  • It is more conductive than copper.
  • It can be made from graphite, also known as ordinary pencil lead.
  • It is only one carbon atom in thickness that is only ~0.345 nm thick.
  • It is ultra-light yet immensely tough.One atom thick layer sheets absorb ~2.3% visible light, making it transparent.
  • It is known to move electrons 200 times faster than silicon because they travel with such little interruption.
  • It is the thinnest material possible as well as being transparent.
  • It is best at electricity. It can carry more electricity more efficiency, faster and with more precision than any other material.
  • It is completely impermeable. Even helium atoms can’t pass through it.
  • It is a super conductor.It conducts heat in all directions that is it is an isotropic conductor.
  • It is very expensive. But the future and opportunities of this material are potentially enormous.
  • It weighs only 0.77 milligrams per square meter and is stretchable up to 20% of its initial length.

Graphene Applications:

Solar cells:

Solar cells rely on semiconductors to absorb sunlight. Semiconductors are made of an element like silicon and have two layers of electrons. Using graphene would also allow cells that are hundreds of thousands of times thinner and lighter than those that rely on silicon.

Water Filtration:

Graphene could be used to distillate saltwater to make it drinkable. Graphene could also be immensely helpful in purifying water of toxins.Passing sea water through Graphene’s tiny pores, the crystal lattice could let water molecules through, while blocking out the atoms that make salt.

Electronics:

Graphene can be used as a coating to improve current touch screens for phones and tablets.This makes it perfect for use in portable electronics. Graphene has a high carrier mobility, and low noise, allowing it to be used as the channel in a field-effect transistor.

Biomedical:

It could also be useful in biomedical research. Small machines and sensors could be made with graphene, capable of moving easily and harmlessly through the human body, analyzing tissue or even delivering drugs to specific areas. Also used to monitor various things such as glucose levels, haemoglobin levels, cholesterol and even DNA sequencing.

Agriculture:

Graphene sensors could boost the effectiveness of monitoring vital agricultural crops.

Cancer Treatment:

The development opens up the possibility of preventing or treating a broad range of cancers, using a non-toxic material.

Energy storage:

This makes graphene a very promising material to be used in batteries and supercapacitors. Graphene may enable devices that can store more energy – and charge faster, too. Graphene can also be used to enhance fuel-cells.

Satellites and cars:

It has properties that provide light but super strong composite material for next generation satellites, planes and cars. Graphene could also reduce the weight of cars or planes, subsequently cutting the burning of fuel.

Batteries:

Graphene could dramatically increase the lifespan of a traditional lithium ion battery. Graphene has the ability to conduct heat and electricity which lend to the development of more rapidly charging batteries.Carrying less weight, and using batteries that can be recharged by body heat or the sun would allow them to stay out in the field for longer.Graphene could dramatically increase the lifespan of a traditional lithium ion battery.

Weatherproofing and packaging:

This technology is applied to brick and stone to weatherproof houses, or even to food packaging to stop the transfer of water and oxygen molecules which causes food to go off.

Sensors:

Every atom in graphene is exposed to its environment allowing it to sense changes in its surroundings. Graphene now allows for the creation of micrometre-size sensors capable of detecting individual events on a molecular level.

Wearables:

Flexible, wearable electronics take advantage of graphene’s mechanical properties as well as its conductivity.

Biomicrorobotics:

Graphene helps to develop nanoscale biomicrorobot. Biomicrorobot or cytobot made by cladding a living endospore cell with graphene quantum dots. The device acted as a humidity sensor.

Magnetic:

Graphene-based magnetic sensor 100 times more sensitive than an equivalent device based on silicon. The sensors were based on the Hall effect, in which a magnetic field induces a Lorentz force on moving electric charge carriers, leading to deflection and a measurable Hall voltage

Composites and Coatings:

​The next generation of composites and coatings can be enhanced by graphene. Its excellent strength, conductivity, flexibility, light weight nature and barrier properties are useful for a wide range of applications. The conductivity and flexibility of graphene also makes it a promising additive for thermoforming plastics and Graphene paints.

Basics Questions about Graphene:

Who invented graphene?

It was originally observed in electron microscopes in 1962, but it was studied only while supported on metal surfaces.The material was later rediscovered, isolated, and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester

Where did graphene come from?

It is produced by separating a single atom layer film from graphite. This can be done as easily as rubbing a graphite pencil on tape, then sticking together and pulling apart the tape until a single layer of graphite remains, which is called graphene.

What are unique properties of graphene?

Graphene conducts electricity better than any other common substance, it is the thinnest known material (one atom thick) and is stronger than steel.

Why graphene is so strong?

The electrical attraction between carbon atoms in graphene is very strong and that is the source of strength for both graphene and diamond.

How is Graphene Made?

You can make it several ways; the simplest way is to simply peel it off a piece of graphite, which is an easy way but it is terribly uncontrolled. There are also other methods to create graphene layers called CVD – Chemical Vapor Deposition.

What is the difference between graphene and graphite?

Graphene could be described as a single, one atom thick layer of the commonly found mineral graphite; graphite is essentially made up of hundreds of thousands of layers of graphene.

What is the difference between graphene oxide and graphene?

Graphene is a carbon nanomaterial with a negligible level of chemical functionality. In contrast, graphene oxide is graphene that has oxygen-containing chemical groups.
The chemical functionality of graphene oxide is known to typically reduce the electrical and thermal conductivity of graphene.

What is the difference between graphene and fullerene?

Graphene is a two dimensional sheet of carbon atoms linked together by single covalent bonds to form a network.
Fullerenes are also made of carbon atoms but in the form of tubes or spheres.

In what chemicals is graphene soluble?

Graphene and fullerenes are sparingly solubility in aromatic solvents such as toluene and benzene. They are also soluble in carbon tetrachloride, carbon disulfide, and 1,2-dichlorobenzene.

Why does graphene have a high melting point?

As its covalent bonds are very strong, and there are many of them, a lot of energy would be needed to separate atoms. This makes graphite’s melting point and boiling point very high.

Emerging applications of Graphene:

Graphene is undoubtedly emerging as one of the most promising nanomaterials because of its unique properties. Graphene could be revolutionary for a wide variety of fields. Currently, the most common techniques available for the production of graphene are shown below.

Porous, 3-D forms of Graphene developed at MIT can be 10 times as strong as steel but much lighter

A team of researchers at MIT has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. This 3-D forms of Graphene material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel.

In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

Graphene-coated solar panel generates Electricity from Rain Drops.

Scientists in China are developing a new kind of graphene coated solar panel that could be used to generate power from rain drops.By using a thin layer of highly conductive graphene, the solar cell could effectively harness power from rain. The salt contained in rain separates into ions (ammonium, calcium and sodium), making graphene and natural water a great combination for creating energy.

According to the scientists , this new technology could guide the design of advanced all-weather solar cells.i-e The new solar cell can be excited by incident light on sunny days and raindrops on rainy days.All-weather solar cells are promising in solving the energy crisis.

MIT discovers new way to turn Electricity into Light, using Graphene

Now, researchers at MIT have discovered a similar process in a sheet of graphene, in which a flow of electric current can, under certain circumstances, exceed the speed of slowed-down light and produce a kind of optical “boom”: an intense, focused beam of light.
This entirely new way of converting electricity into visible radiation is highly controllable, fast, and efficient, and could lead to a wide variety of new applications.

The new finding started from a fasinating observation. The researchers found that when light strikes a sheet of graphene, which is a two-dimensional form of the element carbon, it can slow down by a factor of a few hundred. That dramatic slowdown, they noticed, presented an interesting coincidence. The reduced speed of photons (particles of light) moving through the sheet of graphene happened to be very close to the speed of electrons as they moved through the same material.

Graphene Light Bulbs can save 10% Energy

A dimmable LED bulb with a graphene-coated filament was designed at Manchester University, in UK.  The super-strong material “Graphene” was discovered in 2004 by the researchers at the Manchester University, and they got 2010 Nobel prize in Physics for their Graphene discovery.

This Graphene light bulb is said to cut energy use by 10% and last longer owing to its conductivity. It is expected to be priced lower than current LED bulbs. Graphene is an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice.

MIT creates Transparent, flexible solar cells using Graphene

Imagine a future in which solar cells are all around us — on windows and walls, cell phones, laptops, and more. A new flexible, transparent solar cell developed at MIT is bringing that future one step closer.

The device combines low-cost organic materials with electrodes of graphene, a flexible, transparent material made from inexpensive and abundant carbon sources. This advance in solar technology was enabled by a novel method of depositing a one-atom-thick layer of graphene onto the solar cell — without damaging nearby sensitive organic materials.

Until now, developers of transparent solar cells have typically relied on expensive, brittle electrodes that tend to crack when the device is flexed. The ability to use graphene instead is making possible truly flexible, low-cost, transparent solar cells that can turn virtually any surface into a source of electric power.

World’s Thinnest Light Bulb Created from Graphene

Creating light in small structures on the surface of a chip is crucial for developing fully integrated “photonic” circuits. But researchers were not able to put the light bulb into a chip, as the light bulb filaments must be extremely hot in order to glow, and micro-scale metal wires cannot withstand such temperatures.

Researchers have developed World’s Thinnest Light Bulb using Graphenethat works in the same way as the filament in a light bulb. By measuring the spectrum of the light emitted from the graphene, the team was able to show that the graphene was reaching temperatures of above 2500 degrees Celsius, hot enough to glow brightly.

Graphene Sieve turns Seawater into Drinking water

A new research shows graphene can filter common salts from water to make it safe to drink. The new findings could lead to affordable desalination technology. Graphene-oxide membranes have attracted considerable attention as promising candidates for new filtration technologies.

Now the much sought-after development of making membranes capable of sieving common salts has been achieved. New research demonstrates the real-world potential of providing clean drinking water for millions of people who struggle to access adequate clean water sources. The new findings from a group of scientists at The University of Manchester were published in the journal Nature Nanotechnology.

Revolutionary new Graphene Elastomer exceeds sensitivity of Human Skin

A new sponge-like material, discovered by Monash researchers, could have diverse and valuable real-life applications. The new elastomer could be used to create soft, tactile robots to help care for elderly people, perform remote surgical procedures or build highly sensitive prosthetic hands.

Graphene-based cellular elastomer, or G-elastomer, is highly sensitive to pressure and vibrations. Unlike other viscoelastic substances such as polyurethane foam or rubber, G-elastomer bounces back extremely quickly under pressure, despite its exceptionally soft nature. This unique, dynamic response has never been found in existing soft materials.

 

MIT’s new Graphene-based Dialysis membrane works 10 times faster

Today’s commercial dialysis membranes separate molecules slowly.Now MIT engineers have fabricated a functional dialysis membrane from a sheet of graphene. The graphene membrane, about the size of a fingernail, is less than 1 nanometer thick. The team’s membrane is able to filter out nanometer-sized molecules from aqueous solutions up to 10 times faster than state-of-the-art membranes.

While graphene has largely been explored for applications in electronics, the team’s findings demonstrate that graphene may improve membrane technology, particularly for lab-scale separation processes and potentially for hemodialysis

Graphene Flagship’s Graphene-Based Interfaces Do Not Alter Target Nerve Cells

This work, published in the journal ACS Nano was an interdisciplinary collaboration between various Universities, with nanotechnologists, chemists, biophysicists and neurobiologists all playing an important role.

The Graphene Flagship is a European initiative which promotes a collaborative approach to research with an aim of helping to translate graphene out of the academic laboratory, through local industry and into society.

Scientists have always found the human brain endlessly fascinating and our understanding of the brain has increased to such a degree that by interfacing directly between the brain and the outside world we can now harness and control some of its functions.

 

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