What is Graphene?
Graphene is a single, thin layer of graphite — the soft, flaky material used in the lead of your pencil. Graphite is an allotrope of the element carbon, this means that it contains the same atoms as carbon, but they are arranged in a different way, giving the material different properties. Diamonds are also a form of carbon, yet they have very different properties to Graphite. When Graphene is isolated from Graphite it takes on incredible properties, which is why it is known as a “supermaterial”. While it is only one atom thick, making it the first two-dimensional material ever discovered, it is also one of the strongest materials in the world.
The History Of Graphene
Scientists have theorised whether single layers of graphite could be isolated since the 1960s, but it wasn’t until 2004 that the first isolated sample of Graphene was discovered by Andre Geim and Konstantin Novoselov at the University of Manchester. Incredibly, the the tool used for their discovery was a simple roll of scotch tape. When using tape to polish a large block of Graphite, the researchers noticed exceptionally thin flakes on the tape. As they persisted in peeling layer after layer from the flakes of Graphite, they eventually produced a sample as thin as possible. They had found Graphene. The scientific world was skeptical at first and when Geim and Novoselov wrote a three-page paper describing their discoveries, the Journal Nature rejected their paper.
But, in October 2004, the paper, “Electric Field Effect in Atomically Thin Carbon Films,” was published in the magazine Science, causing a stir across the scientific community. Eventually, in 2010, Geim and Novoselov were awarded the Nobel Prize in Physics for their discovery.
Although it is the thinnest material known in the world, it is a hundred and fifty times stronger than an equivalent weight of steel, in fact, it is the strongest material ever measured. In addition, it is also an excellent conductor of heat and electricity and has interesting light absorption abilities. Although it is extremely thin, it is still a visible material that absorbs about 2.3% of white light and yet is very much transparent to the human eye. Another one of its standout properties is that it is highly flexible. It is as pliable as rubber and can stretch to a hundred and twenty per cent of its length. On the other hand, perfect Graphene is also highly impermeable, and even Helium atoms cannot go through it.
It is truly a material that could change the world, with unlimited potential for integration in almost any industry. Since its discovery there has been a worldwide proliferation of Graphene-related patents. The patents suggest a wide array of applications: ultra-long-life batteries, bendable computer screens, desalinization of water, improved solar cells, superfast microcomputers. Wearable electronic devices made with this material could be made even more useful, designed bend and wrap around limbs, accommodating a range of body movements. 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, analysing tissue or even delivering drugs to specific areas. Carbon is already a crucial ingredient in the human body; a little Graphene added in might not hurt. It can even be a solution to mosquito bites and their potential to spread diseases like malaria, with researchers demonstrating that a Graphene film on the skin would prevent the mosquitoes from biting.
Besides industrial design, Graphene is also used by artists, as the material can create striking imagery due to its array of properties. It has been used to create laser-induced-Graphene art pieces to conductive ink for paintings!
Although the sticky tape method used to first isolate Graphene at The University of Manchester is still used, it is not an efficient way to produce the material at an industrial scale.
One of the methods used to produce larger quantities of this material is called Chemical Vapor Deposition (CVD). During the process, usually a sheet of Copper is placed into a furnace where it is heated to the appropriate temperature. Next Methane and Hydrogen gas are added, which essentially causes pools of Graphene to form. This process allows for large sheets of it to be formed in a relatively short amount of time, which is crucial for commercial applications.
Another approach involves growing Graphene nanoplatelets starting from a Carbon-rich solid, such as sugar. This green method generates the nanomaterial by exfoliating graphite with sugars.
Recently, scientists have been experimenting with another promising technique, known as “flash joule heating,” that aims to convert any Carbon-containing material into Graphene. While it is not a technique that is ready yet, it could prove a significant way of producing Graphene in the future.
The Future of Graphene Research
Graphene has an endless list of strengths, yet there is still a struggle to commercialise and apply it across industries. Unfortunately, it is still expensive to produce in large quantities, limiting its use in any product that would demand mass production. Moreover, when large sheets of it are produced, there is an increased risk of tiny fissures and other flaws appearing in the material. However, research laboratories worldwide — including the University of Manchester, where Graphene was first discovered — are continually filing patents for new methods of creating and using Graphene.