Tech cafe: All things being Graphene

Human civilisation has been witness to stone, bronze, copper, iron and silicon ages, and may now well be transitioning to the age of graphene.

Human civilisation has been witness to stone, bronze, copper, iron and silicon ages, and may now well be transitioning to the age of graphene.

Discovered, isolated and characterised in 2004 by scientists Andre Geim and Kostya Novoselov, graphene, which is a single sheet of carbon atoms that constitute basic 2D structure of graphite crystals, has found widespread application, from telecommunications, power generation, bio-medicine and optics, and has the ability to replace a whole range of elements, including silicon and steel. It has super strength, 200 times more than steel while it is six times lighter in weight. It is anti-corrosive, and excellent conductor of electricity and heat at room temperature. But its property to be chemically transformed to create new combinations is what makes graphene a wonder material.

While graphene has evolved over the last decade with scientists finding many uses of the material, it is yet to be made available on an industrial scale. Given the limited amount of research, scientists are still discovering more uses for graphene that can transform the future.

Recently, a team of scientists at the University of Southampton and the Japan Advanced Institute of Science and Technology (JAIST) have found a new use of the wonder material—as an efficient and a cheap source for detecting air pollution. The sheet interacts with carbon dioxide and volatile organic compound gas found in homes to detect concentration by parts-per-billion, as compared to parts-per-million that most sensors can achieve.

But graphene’s use case is not just restricted to detecting pollution; earlier this year; researchers from Max Planck Institute for Intelligent Systems in Germany created a microbot with an outer layer of the material to absorb lead in water, and scientists in South Korea developed a vessel lined with graphene which can separate oil from an oil spill, collect it and store it in the vessel all by itself without any external power inputs. With the material being a perfect barrier, as helium—which is one of the most difficult gases to contain—cannot pass through it, nano-porous graphene can be used for desalination more effectively, making seawater drinkable.

Graphene can also transform renewable energy, as it has the potential to not just double the efficiency of solar cells, but also create an all-weather solar cell. While solar cells harness the energy of the sun, graphene—with its property of binding positively-charged ions with negatively-charged electrons in water—can produce electricity from positively-charged ions in rain drops, which contain calcium, ammonium and sodium.

While research on the toxicity of the material has been limited, being an anti-bacterial, graphene oxide is used to reduce infections. It has also found its way in bio-medicine with nano-ribbons that are being used for faster DNA sequencing—determining the precise order of organic molecules. The material—it’s a million times thinner than paper—has more potential for being the next frontier in medical diagnostics with bio-sensors and electrochemical sensors for detection of haemoglobin levels, cancer and glucose levels. Scientists in South Korea have developed a wearable patch for detection of glucose levels from sweat; loaded with enzymes and micro-needles, it not just detects glucose, but also releases metformin for treating diabetes.

However, one of the greater uses of the element can be found in the field of telecommunications and optics. Mobile phone giants like Samsung have been working on graphene since 2014 to improve touchscreens and develop flexible screen mobile phones and wearables. The technology can be replicated to television, and given that it can hold electrons for far longer, it is also being used for camera sensors which are a thousand times more sensitive to light. More than that, the use of graphene in Lithium-ion batteries and supercapacitors can improve the battery life and reduce battery size.

Being in existence only for a decade, the costs of producing graphene are very high. Although new methods have brought down the cost by 100 times, it is still not as viable as silicon chips. Moreover, silicon has seen 70 years of research, while patents and research on graphene have been limited. The biggest obstruction for its development is its ability to be a great conductor of electrons. Unlike silicon where one can stop electrons, graphene has no off-switch, so there is nothing to stem the flow of electrons.

With technology evolving fast and companies realising more uses of graphene, the thin, virtually transparent sheet may well be the next big innovation after silicon. But graphene is still some years away from growing on an industrial scale.