Throughout history, the progress of human civilization has largely relied on its capability to discover, extract, and utilize different materials from Earth. Each new material provided benefits that not only equipped the early civilizations for survival but also enabled them to defeat enemies and build a better life. Back in the Stone Age, humans used stone tools. This era later developed into the Bronze Age where, for the first time, humans began working with metal. This further progressed into the Iron Age during which people manufactured tools from iron and steel. Every subsequent age is known by its newly discovered materials that brought new technologies and further development to society.
The age we are living in, in the twenty-first century can be recognized as the Carbon Age. Carbon is the basic element of life, but it may soon become the basic element of the rest of the world as well. Graphite, the stable thermodynamic state of carbon under environmental conditions, has been studied and used by humankind for centuries. When you draw a line on the paper and put pressure on it, then the color turns dark. This happens because graphite consists of thousands of identical layers piled on top of each other; the more layers you leave on paper, the darker the color is. A single layer of graphite is called graphene and has a thickness of a billionth of a meter.
The discovery and synthesis of graphene is one of the most remarkable advances in materials over the last decades. It is the building block of many carbon allotropes (different physical forms in which elements can exist). Graphene has a perfect hexagonal arrangement of carbon atoms held together by covalent bonds into a honeycomb sheet. According to Dr Savjani, graphene is easiest to imagine as a honeycomb sheet of carbon atoms that is completely flat.
A Canadian theoretical physicist, Phillip Wallace, initially conceptualized graphene in 1947. He predicted that if a coated sheet of graphite were to be isolated, it would have certain abnormal and interesting qualities. It was practically discovered by Andre Giem and Konstantin Novoselov at the University of Manchester during their Friday evening experiments in 2004 by using a technique called ‘Sticky Tape.’ They used an adhesive tape to extract the graphene layers from graphite and placed them on silicon wafers. They were awarded the Nobel prize for this simple yet groundbreaking experiment in 2010 which opened the doors to more research.
Graphene has unique characteristics as it retains its original size and shape even if you bend and twist it. Two-dimensional sheets of atoms, also called monolayers, can be made of other materials like boron, silicon, germanium, and phosphorus; they have the suffix -ene tacked in their names (like germanene and phosphorene). Like graphene, they also have some unique properties. Phosphorene has some interesting electrical properties due to the ability of phosphorus to form five bonds (carbon, on the other hand, can only form four bonds). There are many materials competing with each other for benefits they provide but graphene is one of the rising stars with many benefits.
Graphene has a tensile strength of 130 gigapascals — 100 times stronger than steel of the same thickness. Therefore, whenever we think of space elevators, graphene will play a significant role because of its strength. The storage density of lithium-ion batteries is increased about two to three times by the addition of graphene to it. There is no bandgap (energy difference between the valence band and conduction band) found in graphene. If graphene is not having any bandgap then its electrons can occupy any energy level. This creates interesting opportunities in manufacturing solar cells. However, it is not always desirable to have no band gaps. For instance, a bandgap is needed for switching devices like transistors. An impurity added to the graphene can help to accomplish this too.
One of the astonishing characteristics of graphene is it’s extremely lightweight due to which it can be used to make large buildings and bridges. Graphene is transparent due to its ability to absorb 2.3% of the light that shines on it. Moreover, graphene has high electron mobility, a measure of how easily electrons travel in a substance, which is 100 times that of silicon. Boosting the movement of electrons is a way to reduce the size of devices and make them work faster. Thus, graphene is the strongest material in the world stronger than steel but lighter than aluminum and harder than a diamond but more flexible than rubber.
Graphene can transform three major areas: computing and electronics, energy storage, and structural engineering. Ultra-fast graphene computers will not only make all our personal devices much faster but will also open many new areas, particularly in implanted medical electronics. Carbon nanotube (rolled-up sheets of graphene) is one of the most well-known applications in the field of structural engineering. It will create new opportunities, not only due to its low weight and high tensile strength but also because of its ability to make materials that are electrically and thermally non-conductive.
Graphene offers numerous future applications. For instance, it can be used for making flexible displays because of its unique property of folding and bending. Moreover, derivatives of graphene (graphene oxides) can be used for drug delivery, as nano drugs bound to graphene oxide sheets can be used to deliver drugs for anticancer therapies without causing any toxicity. If methods for graphene’s production and processing can be developed and exploited on an industrial scale, this will create a technology boom not only in physical and electrical engineering but also in bioengineering. Some production issues or costs may render some of the above uses impracticable, but if even a fraction of this magic material’s potential can be realized, it will revolutionize the world we live in.