GRAPHENE APPLICATIONS

The interest about the properties of graphene, in the scientific and technological fields, depends on the following aspects of this material:

LOOK AT THIS PRESENTATION: Graphene

This section explains the principal applications of graphene in different fields related to Science and Technology:

FIELD

APPLICATIONS

NANO-ELECTRONICS

Because of its extraordinary electrical properties, graphene is considered a perfect candidate in applications related to the field of quantum computers; these computers are super-fast and are smaller than the computers used today.

The researchers have already realized graphene transistors and simple circuits, capable of operating at very high frequencies, amounting to hundreds of GHz. In particular, in 2010, a research group of IBM succeeded in realizing a transistor made of graphene, with a maximum operating frequency of 100 GHz and with a gate length of 240 nm. Also in 2010 UCLA (University of California, Los Angeles) reached the record speed of 300 GHz for a transistor, in a test with graphene.

In 2011, still IBM created a transistor made of graphene, with a frequency of 155 GHz and with a gate length of 40 nm.

It is important to note that the speed of a transistor is typically assessed on the basis of the switching frequency; a transistor that works in on/off switching is like a switch, so that when closed it conducts, while when open it does not conduct.

Graphene transistor

ELECTRONICS

  1. Graphene can be folded and stretched, without losing its electrical properties, for this reason, it is an ideal candidate in applications relating to the realization of:

    • flexible electronic devices

    • rollable iPhones

    • folding tablets

    • roll-up televisions

    • electronic devices “wearable”

    definitely unrealizable with a technology based on silicon. Silicon, currently used in Electronics, is a crystalline material, fragile and not suitable in applications where flexibility is required.

    In the era of graphene, namely “the era of the two-dimensional materials”, the electronic devices “wearable” will fit perfectly into our body. The mobile phones, for example, could be worn as bracelets and you might bend them depending on the need.

    Aspect of silicon

    Several electronics companies like IBM, Samsung, Sandisk, Xerox, Nokia, are competing through the creation of many patents.

  1. Graphene, due to the high optical transparency in the visible, infrared and ultraviolet light and due to the high electrical conductivity, is considered a perfect candidate to replace the indium-tin-oxide (ITO) electrodes with transparent conductive electrodes, in applications such as:

    • touch screens

    • liquid crystal displays

    • organic solar cells

    • OLED (Organic Light Emitting Diode). An OLED is a very thin display; it does not require additional components to be illuminated and it is able to produce own light. On the contrary a liquid crystal display is illuminated by an external light source.

    From a long time, the electronics companies have looked for an alternative material to ITO, because of the high cost of indium. Carbon nanotubes have been taken into account with little success; in fact, small defects are formed in visible areas, called "dead pixels”, if they are used in a display.

    In this context, an important step has been done, thanks to a group of Korean and Japanese scientists, which belong to the team of Byung Hee Hong and Jong-Hyun Ahn at the Sungkyunkwan University in Seoul; they have produced graphene films using the chemical vapor deposition on a flexible copper substrate. The graphene films have rectangular shape with diagonal of 76 cm and electrical resistance higher than the resistance of commercially available transparent electrodes made of ITO. One graphene film allows the passage of about 90% of the light, therefore it has a good transparency.

    The team has used these graphene films as electrodes in a touch-screen panel; this kind of touch-screen has proved to have better performance than those with ITO electrodes. The team has observed also a resistance to the stretching more than doubled, compared to the resistance of an ITO electrode. The results about the production of graphene films for transparent electrodes have been published in the “Nature Nanotechnology” journal.

  1. Graphene is a good candidate for the realization of high capacity batteries; in fact, this material acts as a capacitor, capable of accumulating the electrical energy produced by solar cells.

    These graphene-based super-capacitors have a specific energy density of 85,6 Wh/kg at ambient temperature and of 136 Wh/kg at 80°C, practically similar to that of nickel-metal hybrid batteries, but with the advantage that, the graphene super-capacitors can be reused an indefinite number of times and can be loaded and unloaded very quickly.

VIDEOCOMMUNICATIONS

The world of video communications will see the graphene as protagonist in advanced applications, such as:

  • satellite navigation systems integrated into the car's windshield

  • television screens embedded in the windows

BUILDING FIELD

The use of graphene regards projects based on new types of "intelligent" windows, capable to become dark on command or be used as photovoltaic devices for the production of electricity from sunlight.

GREEN TECHNOLOGY

Graphene is a resistant, and at the same time, lightweight material; it has proved to be suitable in:

  • the aviation industry - in this field, graphene could be applied, in thin sheets, as a coating of the airplane wings, to protect them from lightning strikes and external agents; otherwise, thin graphene sheets could be used to monitor any aircraft failures. Another application of graphene is the use as lubricant. In fact, graphene can be diluted with other materials, so it is possible to obtain an infinite variety of new products, said composite, which can be found in the solid and liquid state;

  • the production of more efficient wind turbines, because of the lightness of the material, combined with its high conductivity;

  • the construction of solar panels entirely made of carbon, allowing the elimination of metals, difficult to dispose of;

  • the desalination of the sea water with a minimum waste of energy. In the simulations carried out, graphene has proven to be able to desalinate seawater through a method, which is hundreds of times more efficient than the traditional techniques of reverse osmosis and with lower costs.The Lockheed Martin Aerospace engineering company has already patented a concrete project; it consists of large graphene layers, in the form of special perforated sheets, called "perforene"; in practice, a layer of perforene retains the salt and lets through only the water;

    Find out more: A new approach to water desalination

  • the storage and transportation of hydrogen. The technique consists in the absorption and the controlled release of hydrogen on the surface of thin graphene sheets, which have been corrugated and compressed;

  • the detection of pollutants; in this case graphene acts as a highly sensitive sensor; in fact, due to its ability to adsorb gases, the resistance of this material changes if only one molecule is adsorbed on its surface; this variation can be detected due to the very low background noise, guaranteed by the crystal lattice perfection and the high electrical conductivity of graphene.

AUTOMOTIVE FIELD

and

AEROSPACE FIELD

The carbon fiber that is currently used in the automotive and aerospace fields, could be replaced with lightweight and extremely strong elastic materials, based on graphene.

SPORT

Graphene has been already applied in the construction of sophisticated tennis-rackets:

This material is used in the central part of the racket frame, in order to ensure a decrease of the mass in this area and to allow its redistribution in the most strategic areas, such as on the tip of the racket and on the handle. The equal distribution of the weight between the tip and the handle provides a better maneuverability to the tennis player and allows him to make less effort in hitting the ball, getting even a significant increase of the speed imprinted to the ball.

The graphene tennis-racket was used successfully, for the first time, by Novak Djokovic and Maria Sharapova at the Australian Open, 2013 edition.

Look at this video - Graphene: Composite Materials

BIOMEDICAL FIELD

The graphene oxide has shown bactericidal properties and it may also be used in products for the hygiene and for the preservation of foods.

MEDICINE

  • Exploiting the capacity of particular molecules, susceptible to certain diseases, to bind to carbon atoms, it will be possible to use graphene also to create new diagnostic tools, very similar to the "tricorder", used by the doctors in the universe of "Star Trek" science fiction.

  • Graphene can be used in the regeneration of body tissues or in the creation of bionic implants such as artificial retinas.

Some applications of this extraordinary material have been presented at the "Mobile World Congress 2016" in Barcelona.

Unfortunately, at the time, the commercial use of this material comes up against prohibitive economic logic. In fact, the production of graphene on a large scale is still an expensive process. The cost to produce one kilogram of graphene is amounting to tens of thousands of euros (approximately 35,000 euros) . The idea that graphene can replace silicon in the future processors remains, for now, a dream and it is a challenge in Electronics field.

Then we have to stay ready to a new industrial revolution, in which everything will be produced with graphene, already considered “the plastic of the third millennium”.


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