Graphene, for anyone who’s unaware, is pure carbon in the form of a thin, one atom thick layer. It’s very lightweight, but remarkably strong, and also conducts heat and electricity very well. As such, it’s been touted as a ‘miracle material’, for its potential use in electronic devices and many other applications - its discoverers were awarded the Nobel Prize in Physics.
The challenge with graphene is producing large quantities of it, at a high quality, but also a low cost. Several methods are currently used, but research is still continuing in the area.
One of the first methods was a rudimentary one - the original discoverers at Manchester University used scotch tape to peel layers of carbon atoms off of graphite (an allotrope (form) of carbon). Further layers can be peeled off from these layers using the same method, until a single layer is left. This layer can then be transferred onto a silicon wafer. The issues with this method are obviously that it’s quite time-consuming, and doesn’t create a great deal of the material.
Another method is the use of Chemical Vapour Deposition (CVD), which can produce higher quality graphene. This involves carbon atoms in the gas phase being deposited onto a substrate surface, to create a thin film of graphite. This method has the issue that the graphene can subsequently be hard to remove from the substrate.
More recently, scientists in Dublin have pioneered a new method for creating graphene, using a technique called ‘shear mixing’. This involved placing it into a laboratory mixer, with a surfactant liquid, which sheared off layers of graphene when turned on. They replicated their experiment using a kitchen mixer and washing up liquid as a substitute - as a result of this, you might have spotted it in the news, with a variety of news outlets loudly urging you to ‘MAKE GRAPHENE IN YOUR KITCHEN!!”. Sadly, the exact mix of graphite and surfactant required needs to be precisely determined, using expensive analytical equipment, and not all of the graphite is converted into graphene, so separation needs to be carried out afterwards. Still, their method allowed them to produce 5 grams of graphene per hour on a very small scale - so scaled up it could be the best method yet for producing large amounts of the substance.
References & Further Reading