The little allotrope that might – does graphene still have potential?

Graphene was promised to be the next big thing. I remember being told by my chemistry teacher about this miraculous discovery at Manchester University. Graphene has humble origins and its original production process is near-trivial. All it took is two smart guys to stick cellotape to a rock and peel it off.

Nevertheless, graphene has been hailed as the greatest material discovery since plastic. It is incredibly light, and orders of magnitude stronger than steel. It can also conduct electrons at near-light speed. Properties not seen in any other material.

But what exactly is graphene? Graphene is the first two-dimensional material discovered, a sheet of single carbon atoms in a hexagonal lattice. It can be considered the finest carbon structure possible and it was originally derived from graphite. In even simpler terms, graphene is the result of a hypothetical pairing of flat Stanley and a carbon-based superman[1].

Graphene, like plastics, can be used in almost every industry. From aerospace manufacturing to implants, consumer electronics, and batteries. However, graphene has struggled to take off since its discovery in 2004. This is primarily due to the costs and difficulties of mass production. Cheaply produced graphene will be riddled with silicon impurities [2]. Graphene needs to be modified for practical applications. For example, it is so conductive that the material has no natural band gaps, areas which lack electronic charge. The current king of electronics, silicon, is a semi-conductor. This means silicon allows for a stop-go flow of electrons, a vital feature for electronics that graphene is too conducive to emulate [3].

Artificial band-gaps can be introduced into graphene, but it often involves large costs in addition to the existing difficulties of mass production. This, until recently, could only be done through complex methods such as chemical vapour deposition. These methods would often result in toxic chemical by-products at best and completely unusable samples of graphene alongside the toxic by-products if done incorrectly. [4]

However, there have been recent developments on the issues of graphene mass production, and the lack of natural stop-gap, aka the excessive conductivity problem. In 2020, researchers at Rice University developed a much cheaper method of graphene manufacture known as ‘flash graphene’. Flash graphene is produced by heating up any solid carbon material to 5000 degrees kelvin for 10 milliseconds, which is 4726.85 degrees celsius. This allows for the majority of the carbon bonds of the product (e.g a car tyre or plastic waste) to break and leave the lucrative thin sheets of graphene behind. However, this cheaper and more industrial-friendly production process comes at a quality cost [5]. Research marches on, with Rice now employing machine learning to fine-tune their process and improve the quality of the flash graphene product [6].

Meanwhile, on the conductivity front, the Catalan Institute of Nanoscience and Nanotechnology recently made a breakthrough. The researchers developed a ‘bottoms-up’ approach of bonding carbon atoms to result in a form of graphene with similar semi-conducting capabilities to silicon [7].

These developments are promising, but they also reveal the complexity and multifaceted nature of material science research. Many problems are being worked on at once. Yet the common denominator issue is always profitability and the market. Encouragingly, costs have been falling, and that original potential from 2004 may still lie within this humble hexagon.