Graphene | The Material of the Future
There have been many exciting advancements in the field of materials science in the past quarter century. Perhaps none has generated the enthusiasm and excitement as the substance known as Graphene. This substance is pure carbon in the form of sheets one atom thick. Graphene is estimated to be 200 times stronger than steel, is as flexible as rubber, and conducts heat and electricity extremely efficiently. Further, because it is only an atom thick, it is nearly two-dimensional, imbuing it with many interesting light-related, and water-related properties.
Graphene is not a naturally occurring substance. Even though it had been theorized by physicists since the 1960s, it was only produced for the first time in 2004. Back then, production methods made Graphene usage prohibitively expensive; however, over the past decade, academics and corporate researchers have made great strides in reducing production costs. And as those costs drop further with each passing year, Graphene is poised to revolutionize the fields of medicine, electronics, computing, and more.
In this article we will look at 1) overview of materials and R&D, 2) discovery of Graphene, 3) properties of Graphene, 4) benefits of Graphene, 5) Graphene production, 6) commercial usage of Graphene, and 7) current & potential applications of Graphene.
OVERVIEW OF MATERIALS AND R&D
While Graphene may have garnered considerable public interest, it remains to be seen exactly how much impact it will have. And each day, physicists and chemists are delving deeper into the physical world, learning more and more about the building blocks of our world and how they may be harnessed to build new things.
Notable developments and trends
Shortly after Graphene’s discovery in 2004, the editorial team at Materials Today compiled a list of the top 10 breakthroughs in materials science in the past 50 years. Graphene was notably absent from the list, but present were some of the biggest areas of discovery and commercial interest, including:
- Carbon fiber reinforced plastics – used in racecars, and bikes, among other applications;
- Materials for Li ion batteries – used in laptops and cellphones;
- Carbon nanotubes – few commercial applications currently, but these will likely play a central role in emerging nanotechnologies;
- Metamaterials – recent experiments involving these resulted in a prototype invisibility cloak.
By 2013, however, the American Society of Mechanical Engineers noted Graphene production as number one of their top five trends in mechanical engineering, along with:
- Electric ink, which would allow people to “write” their own circuit boards;
- Multi-ferroics, which could significantly enhance data storage;
- Nano anodes, which could create rapidly rechargeable batteries; and
- Nanotube threads, which could be used to eventually build a space elevator.
Key players in materials R&D
Because of their various applications, research in materials science is performed and funded by a diverse group of players. Many governments allocate research funding for innovations that have the potential to have tangible economic impact. Militaries have interests in many of these discoveries; for example, the U.S. Army has provided funding for the metamaterials experiments surrounding the invisibility cloak. Academics often lead the way in research, with breakthroughs often resulting from teams for researchers from disparate universities. Outside of governments, militaries, and institutions of higher education, much direct investment in materials science research comes from corporations.
DISCOVERY OF GRAPHENE
Graphene existed in theory in 1962, when chemist Hanns-Peter Boehm described it in a paper published in the Journal of Inorganic and General Chemistry. But in 2003, Russian physicist Andre Geim, then studying at the University of Manchester, set about to produce it. He used scotch tape to pull up progressively thinner layers of graphite, and then dissolved the tape, which eventually left him with the first instances of Graphene. In 2004, Geim and his research colleague Kostantin Novoselov, published an academic paper on the discovery, which has since become one of the most widely cited papers in the field of physics. For this work, he and Novoselov received the Nobel Prize in Physics in 2010.
Graphene – 200 times stronger than steel
PROPERTIES OF GRAPHENE
Graphene is a hexagonal lattice of carbon atoms bonded tightly together. Its sp2 hybridisation – a double bond between the carbon atoms, coupled with its especially thin atomic thickness, fuel its special properties. Its ability to conduct electricity and heat so effectively are believed to be a function of the carbon bonds being very small and strong. Being composed of singular carbon atoms, Graphene is also so thin as to be effectively two-dimensional, in addition to being extremely light weight.
BENEFITS OF GRAPHENE
Graphene’s benefits are closely tied to its properties, which make it tremendously attractive as a raw material for the production of a wide variety of commercial goods. In short, Graphene’s major benefits are that it is highly conductive – 200 times more conductive than silicon, and conducts heat very efficiently as well; thin – enough to be considered a 2D material; transparent; strong – approximately 200 times stronger than steel; light-weight; and flexible, while maintaining its strength and conductivity.
What is Graphene
As of 2014, Graphene is still a fairly expensive material to produce, though innovations in the production process have already reduced its price per cm. There are two main methods for producing Graphene: exfoliation and epitaxy.
The academic and commercial use of exfoliation, known as mechanical exfoliation, to produce Graphene is a refinement of the process Geim and Novoselov used to first produce it. It produces flakes of varying sizes (in powder form), which are considered natural Graphene, in volume. These readily have applications in polymer, paint, and lubricant production. There is also liquid-phase exfoliation, in which graphite is suspended in liquid and then exposed to high frequencies of sound to produce Graphene flakes.
Producing Graphene through epitaxy (also known as chemical vapor deposition or CVD) involves heat treating a susbstrate, such as silicon carbide, nickel, copper or iridium in a gaseous atmosphere that reduces the substrate into Graphene. It produces a film of Graphene (considered synthetic Graphene), that is free of the impurities in natural Graphene, and lends itself readily to use as various electronic applications, and potentially even clothing. It is also the more expensive of the two methods.
COMMERCIAL USAGE OF GRAPHENE
Firms using Graphene
While Graphene is still a relatively new material, many firms are racing to adopt it. These include, but are not limited to big name electronics brands, such as Samsung, IBM, Nokia, Google, SanDisk and Apple, who are looking for ways to incorporate it in their products. In 2013, a UK intellectual patent report noted that Samsung led all firms in Graphene-related patents with 405 worldwide. Given the growing market for the material graphite company Graftech International; deposition technology company Aixatron; UK-based Applied Graphene Technologies and more, are rapidly scaling up their research and production of Graphene to meet demand.
Challenges of using Graphene
The biggest challenge to the commercial usage of Graphene is the production cost. As of 2013, some vendors were charging as much as $60 per square inch, according to a recent Forbes article. This makes the integration of the material into electronics cost prohibitive. The manufacturing processes themselves are nascent, and, while they can reliably produce Graphene, they are in need of further refinement to bring the price point down. Another significant challenge is the fact that Graphene is such a good conductor that it cannot be switched off. It lacks what is known as a band-gap, which means that it cannot be adopted into electrical systems; however, recent research has seen promising developments addressing that problem.
Projected growth of the Graphene market
However, most experts agree that Graphene has enormous upside potential. Not only are firms and universities racing to procure patents, but Graphene’s wide-range of potential applications ensure that demand will continue to grow. Research and Markets’ October 2013 “Global Graphene Market report” forecasts that the compound annual growth rate for Graphene is 60.4% over the period 2012 to 2016. This is driven primarily by massive R&D expenditures from major firms like Samsung and IBM, as well as Graphene’s own attributes. In 2013, the European Union announced its plans to fund Graphene research that drives innovation and job growth over the next decade to the tune of €1 billion.
CURRENT & POTENTIAL APPLICATIONS OF GRAPHENE
The enthusiasm of corporate and academic researchers is understandable. Graphene’s current and potential applications are astounding and could revolutionize many products, markets and fields. These include:
Applications include the development of bioelectric sensors and bio imaging devices, drug and gene delivery, more effective powerful disinfectants, and DNA sequencing – pending safety and clinic trials, of course. Artificial implants are also being explored, that would be connected directly to your neural system, harnessing Graphene’s conductive properties. Graphene could also be used to produce more effective spinal surgical equipment.
Graphene can be used to radically improve the processing power of computer chips. In January of 2014, IBM announced that they had created a Graphene chip 10,000 times faster than standard chips. This was an analog chip, not a digital one, due to Graphene’s band gap. But future R&D will likely bring us computers with Graphene –based CPUs that are more powerful than our current devices by several orders of magnitude, and that consume less energy.
Graphene enthusiasts have long been touting Graphene’s potential to replace silicon in common electric circuitry but the band gap remains the challenge. However, Graphene’s transparency and flexibility will undoubtedly eventually transform the field of electronics. Scientists have been experimenting with quick charging batteries, high-quality headphones, flexible electronics, more capable photo-sensors, and virtually unbreakable touch screens, among other applications. The integration of Graphene into the field of optical electronics could lead to the eventual development of updatable e-paper, among other exciting new breakthroughs.
Graphene filters water and practically nothing else, making it perhaps the most effective water filtration material available. Lockheed Martin has a Graphene water filter in development, which they claim will reduce the energy costs of desalination plants by 99% but it is not yet on the market. Graphene production remains a challenge, but Graphene oxide, which is easier to produce, has similar water-related properties and is much easier and cheaper to produce. This could not only play a significant role in increasing the amount of potable drinking water worldwide (especially in developing countries), but could also have a tremendous effect on alcohol distillation methods.
While Graphene is an extremely efficient water filter, researchers at Vanderbilt University have found ways to apply it to other materials in ways that cause those materials to become either superabsorbent or super repellent. This has tremendous commercial potential when you consider waterproof materials, electronics, and buildings. Nokia is already working on developing a waterproof smartphone.
Graphene’s ability to conduct heat and electricity extremely effectively lend it to the development of more rapidly-charging batteries. Prototype Graphene smartphone batteries in development at UCLA and elsewhere charge fully in mere seconds. Graphene-based super capacitors are being explored for eventual usage in cellphones and other portable devices.
Another application is in the production of more proficient photovoltaic cells, which could be used in clothing, and is of particular interest to firms developing wearable tech, such as Wearable Solar. Even the U.S. military is looking into photovoltaics to power military equipment in the field. As Graphene research and development continues, it will doubtlessly be integrated into commercial and military photovoltaic production.
Graphene’s incorporation into other materials, such as paint, plastic, and polymer production, is being explored. A Graphene–based paint, applied to a device or a house for example, could conceivably also store solar energy, powering the device or home.
Graphene’s strength and light weight lend themselves to the production of goods and parts typically utilizing plastics and polymers, such as car and plane parts. Composites of Graphene plus plastics or polymers could be industry standards for everything from bikes to wind turbines in a few short years.
Graphene is also being studied as a potential material for 3D printing. 3D printing is a type of additive manufacturing process in which printers can rapidly produce three dimensional objects from a digital file. This process has been used to print objects as simple as lampshades and as complex as one-story house.