Graphene ink could lead to flexible gadgets


Ever since 2010, when two scientists from Russia received the Nobel Prize for Physics, everyone is talking about graphene, the amazing material of this millennium. It all started back in 2004, when a group of researchers led by Andre Geim have exfoliated graphite and have discovered an excellent conductor of electricity: graphene. To learn about graphene, we must start from carbon. This element may exist in nature in various forms, with different physical properties such as diamond, graphite (amorphous carbon), carbon nanotubes and fullerenes (it was discovered in 1985 and it led to a Nobel Prize in 1996). Graphene is the basic element of the last three from the previous list, therefore we can assume that it is found in large quantities in nature (because graphite resources are pretty large at this time).

Why is it so important?

Graphene is the best known conductor so far. The graphene sheets are highly stable in normal conditions of temperature and pressure and they have high mechanical resistance. In addition, graphene is practically transparent. In the study of atoms, this feature of graphene can be a giant step further. For example, using the graphene, scientists have managed to study for the first time single atoms of hydrogen. In their experiment, the hydrogen atoms got “stuck” to the graphene, so they’ve stopped vibrating. In such condition, they have been relatively easily observed and photographed by the scientists. Graphene sheets represents the thinnest material possible since it is composed of a single layer of carbon atoms.

Graphene-based ink
At this moment, there are graphene paper circuits based on graphene paper. But researchers at Northwestern University went one step forward and created a graphene-based ink that can be used in ink-jet printers. Graphene based inks will lead to ultra-thin layers of circuits created from malleable graphene, and this type of technology could be used to create circuits on a wide range of materials. Before this discovery, the only problem was to find a usable method of applying the ink. While other approaches of the problem tried to create printed graphene circuits with relative success, Northwestern’s ink is 250 times more conductive than any of the results of other studies and experiments.

Before this, a major part of the problem was in the way scientists harvested the graphene: they needed to “peel it off” from the graphite using an oxidation process that significantly reduces the conductivity of the resulted graphene. In contrast to this technique, researchers at Northwester University used ethanol and ethyl cellulose to exfoliate the graphene. The process can take place at normal room temperature without affecting the conductivity of the resulted graphene. Besides this, the process does not result in a lot of debris. The final product is a powder containing a high concentration of nano graphene powder that can be combined with a solvent to create a graphene ink. The resulted ink can beĀ  used in an ink-jet printer.

So far, scientists have applied this technology to create very complex conductive patterns of 14 nanometers thick by printing multiple layers of ink on a flexible substrate. According to them, even when the substrate was extensively bent, the printed ink did not showed a change in conductivity. When this new discovery gets implemented to electronic devices, we can expect thinner gadgets, foldable gadgets and maybe cheaper gadgets.

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