Graphene Times

Graphene ribbons

WHAT ARE GRAPHENE RIBBONS?

  

Graphene ribbons, are strips of graphene with ultra-thin width. Graphene ribbons were introduced originally as a theoretical model by Mitsutaka Fujita and co-authors to examine the effect of the edge and nanoscale size in graphene.

Production

Large quantities of width controlled graphene ribbons can be produced via graphite nanotomy process, where the application of sharp knife diamond in graphite produces nanobloques of graphite, which are exfoliated to produce graphene ribbons. Also it can be produced by cutting or unzip nanotubes. Another technique by Dai group graphene ribbons were produced by plasma etching of nanotubes partly embedded in a polymer film. More recently, graphene ribbons have been grown onto silicon carbide substrates using ion implantation followed by vacuum or laser annealing. 

Electronic structure

The electronic states of GNRs largely depend on the edge structures. Zigzag edges provide the edge localized state with non-bonding molecular orbitals near the Fermi energy. They are anticipated to have large changes in optical and electronic properties from quantization. Calculations based on tight binding predict that zigzag graphene ribbons are always metallic while armchairs can be either metallic or semiconducting, depending on their width. However, DFT calculations show that armchair ribbons are semiconducting with an energy gap scaling with the inverse of the graphene ribbon width. 

Indeed, experimental results show that the energy gaps do rise with decreasing graphene ribbon width. Graphene ribbons with controlled edge orientation have been fabricated by scanning tunneling microscope lithography. Opening of energy gaps up to 0.5 eV in a 2.5 nm wide armchair ribbon was reported. 

The 2D structure, high electrical and thermal conductivity, and low noise make graphene ribbons a possible substitute to copper for integrated circuit interconnects. Some research is being done to create quantum dots by changing the width of graphene ribbons at select points along the ribbon, creating quantum confinement.

Graphene ribbons possess semiconductive properties and may be a technological alternative to silicon semiconductors.

Polyremic composites

Graphene ribbons and their oxidized counterparts called graphene oxide ribbons have been investigated as nano-fillers to progress the mechanical properties of polymeric composites. Raifee, Koratkar, and Tour et al. report increases in the mechanical properties of epoxy composites on loading of graphene ribbons. 

In a recent study, Lalwani, Sitharaman and co-workers report an increase in the mechanical properties of biodegradable polymeric composites of poly (propylene fumarate) at low weight loading of oxidized graphene ribbons, fabricated for bone tissue engineering applications.

More informacion about graphene ribbons click here.

Graphene companies

KNOWING ABOUT SOME GRAPHENE COMPANIES

Before starting to talk about graphene companies, let’s talk a bit of graphene. The graphene is a new dimensional nanometric material, obtained in 2004. Its production is, up to today, restricted to laboratory level, however, are carried out arduous research to produce industrial scale due to the extraordinary properties that exhibits, such as an anomalous quantum Hall effect, a behavior as gap semiconductor surface and absence of electronic location, among others, all of whom are emerging that will be of great utility in computing, electronics, and ecology. 

This is why many companies have shown interest in this material. Forming part of the graphene companies recognized by the elaboration of products with graphene.

This is a list of a few graphene companies.

GRAPHENEA

Graphenea is a company founded in 2010 Spain. It is a company that manufacture, produce and supply graphene for industrial and research needs. This graphene company are specialize in the making of CVD graphene films and graphene oxide.

GRAFOID

Grafoid is a Canadian graphene research, development and investment company partnered with Focus Graphite Inc. This company invest in, manage, and develop markets for processes that produce economically scalable, pristine graphene for polymer and non-polymer, energy storage and other applications. 

PlanarTech

PlanarTech is one of the graphene companies located in United State that offers graphene samples and Korean-made thermal CVD systems worldwide. The company is targeting corporate and academic R&D labs. Its graphene samples contain graphene on copper foil, SiO2, PET, PI, glass and other substrates, graphene on UV tape, large-area single-crystal graphene and other custom samples.

2-DTech

2-DTech, owned by the University of Manchester creates and supplies 2D materials, including CVD-made graphene, graphene platelets, graphene oxide and other two dimensional materials. The company also offers prototyping of graphene based devices.

One of 2-DTech suppliers is graphene industries, who's partly owned by the University of Manchester as well.

Aixtron

Aixtron AG is a provider of deposition equipment to the semiconductor industry. The company's technology solutions are used to build innovative components for electronic and opto-electronic applications based on compound, silicon, or organic semiconductor materials. For graphene development and production, Aixtron offers the BM Pro systems. BM Pro systems can be used to deposit graphene using both Chemical vapor deposition (CVD) and Plasma-enhanced chemical vapor deposition (PECVD).

These are some of many known graphene companies. Over time more graphene companies will emerge, which will develop more innovative products.

More information about graphene companies click here

Graphene applications

OUTSTANDING GRAPHENE APPLICATIONS

Graphene is as useful material as any discovered on earth. Its remarkable properties as the lightest and strongest material, compared with its ability to conduct heat and electricity better than anything else mean that it can be integrated into a huge number of graphene applications.

Its outstanding properties make it attractive for graphene applications in flexible electronics.

Some graphene applications will be or can be the following.

Biological Engineering

Bioengineering will definitely be a field in which graphene will become a vital part of in the future; though some obstacles need to be overcome before it can be used. Current estimations suggest that it will not be until 2030 when we'll begin to see this graphene applications extensively used in biological field as we still need to understand its biocompatibility.

Integrated circuits 

Graphene has the ideal properties to be an outstanding component of integrated circuits. Graphene has a high carrier mobility, as well as low noise, allowing it to be used as the channel in a field-effect transistor. The concern is that single sheets of graphene are hard to produce, and even harder to make on top of an appropriate substrate. Researchers are looking into methods of transferring this one of graphene applications from their source of origin onto a target substrate of interest.

Composite Materials

Graphene is strong, stiff and very light. Currently, aerospace engineers are including carbon into the production of aircraft as it is also very strong and light. However, graphene is much stronger whilst being also much lighter. Eventually it is expected that graphene is used to create a material that can replace steel in the structure of aircraft, improving fuel efficiency, range and reducing weight. With this graphene applications engineers try to create stronger but lighter devices.

Photovoltaic Cells

Offering very low levels of light absorption as also offering high electron mobility means that graphene can be used as an alternative to silicon in the manufacture of photovoltaic cells. Silicon is commonly used in the production of photovoltaic cells, but while silicon cells are very expensive to produce, graphene based cells are potentially much less so. When materials such as silicon turn light into electricity it produces a photon for every electron produced, meaning that a lot of potential energy is lost as heat.

Ethanol distillation 

Graphene oxide membranes will allow water vapor to pass through, but have been shown to be resistant to all other liquids and gases including helium. This phenomenon has been used for further distilling of vodka to higher alcohol concentrations, in a room-temperature laboratory, without the application of heat or vacuum normally used in traditional distillation methods. Further development and commercialization of such membranes could revolutionize the economics of biofuel production and the alcoholic beverage industry.

Other graphene applications are:

• Solar cells
• Quantum dots
• Transistors

  

For more other graphene applications click here.

Graphene technology

WHAT IS GRAPHENE TECHNOLOGY?

The graphene technology, one of the thinnest, flexible, strong materials and with major conductivity that exist, is set to revolutionize the future, from major changes in the mobile phone industry, telecommunications or the manufacture of chips up to how to develop anti-cancer drugs.

Definitions of Graphene technology.

• Graphene technology is a single carbon atoms layer placed in a hexagonal grilles. A graphene sheets stack forms the crystal graphite.
• Graphene technology is a thin layer of pure carbon; it is a single, lattice layer of carbon atoms that are attached together in a hexagonal lattice.
• Graphene technology is a great heat conductor at room temperature and also an extraordinary electricity conductor. It is a thin and light as a sheet of paper. And also stronger than the silicon. All this at one atom thick.

The graphene technology is a substance formed by pure carbon, with atoms arranged in a regular hexagonal pattern similar to the graphite, but in a sheet of thick atoms. It is very light, weights 0, 77 milligrams.

Andre Geim and Konstantin Novoselov received the Nobel Prize in Physics 2010 award for their great discoveries about the two-dimensional graphene material.

Discovery 

The sudden increase in the scientific interest due to the graphene technology can give the impression that this is a new material. In fact is known and has been described since half a century ago. The chemical bond and the structure is described in the 1930s. Philip Russell Wallace calculed for the first time (in 1949) the electronic bands structure. 

The graphene technology was given little attention for decades to think that was a thermodynamically unstable material as it was thought that the fluctuations in temperature would destroy the order of the glass giving rise to the crystal 2D should be merged. Under this perspective it is understood that the revolution meant that Novoselov and Geim incrementally isolate graphene to ambient temperature. The word graphene was officially adopted in 1994, after having been designated interchangeably, in the field of surface science - "monolayer of graphite". 


In addition, many newly discovered nanostructures, such as carbon nanotubes, are related to the graphene. Traditionally, these nanotubes have been described as "sheets of graphene rolled on themselves" .In fact the properties of carbon nanotubes are explained and understood easily from the inherent in the graphene. It has been also described the preparation of nanotiras of graphene by nanolithography, making use of a scanning tunnelling microscope.

For more information about graphene technology click here

Graphene proterty

DO YOU KNOW ANY GRAPHENE PROPERTY?

One graphene property is that it is a perfect thermal conductor. Its thermal conductivity was recently measured at room temperature and is much higher than the value observed in all the structures of carbon nanotubes of carbon, graphite and diamond.

The ballistics of the thermal conductance graphene is isotropic, that is to say, equally in all directions. In a similar manner to the other physical properties of this material, its two-dimensional structures are particularly special.

The study of the thermal conductivity of this graphene property can have important implications in electronic devices based on graphene. As devices continue to shrink and increases the density of the circuit, high thermal conductivity, which is essential for the dissipation of heat efficient to keep fresh electronics, plays an increasing role in the reliability of the device.

Second graphene property is one of the thinnest material ever made, is still visible to the eye. Due to its unique electronic properties, absorbs a 2.3 % of the light that passes through it, which make it visible enough.

A third graphene property is that the graphene is similar to the surface of graphite, graphene can adsorb and desorb different atoms and molecules. Weakly attached adsorbates often act as donors or acceptors and lead to changes in the carrier concentration, so graphene remains highly conductive.

A fourth graphene property is that is flexible but hard at the same time. graphene is harder than diamond and steel. Although the graphene is so strong, it is also very elastic. The graphene can stretch up to 20% of its original length. It is expected that this graphene property you will find applications in a new generation of strong and flexible screens for mobiles.

Fifth graphene property is graphene is a great conductor. One of the hottest areas of graphene research focuses on the intrinsic electronic properties; how electrons flow through a sheet – only one atom thick – while under the influence of various external forces.

Why is this graphene property so interesting?

In the first place, the graphene is great conductor; electrons are able to flow easily through graphene than through the copper. The electrons travel through the graphene sheet, as fast as just one hundredth that of the speed of light.

Secondly, the electrons in graphene behave manner makes it very useful to explore some fundamental physical properties. Graphene’s near perfect crystal lattice mean it is a very clean system in which to experiment. By restricting the electrons to only two dimensions. 

For more information about graphene property click here