Researchers at The University of Manchester have developed a method of producing water-based and inkjet printable 2D material inks, which could transform 2D crystal heterostructures from the lab issues into real products. Together with the University of Pisa scientists have demonstrated that efficient light detectors, and devices are able to store information encoded in binary form.
Starting from the fact that graphene is the world’s first 2D material: it is 200 times stronger than steel, lightweight, flexible and more conductive of copper, it has opened the path to the family of 2D materials. Using graphene and other 2D materials, it is possible to layer these materials, similar to stacking bricks of Lego in a precisely chosen sequence, known as “heterostructure”, to create devices for specific purposes.
“The inks are produced with a process traditionally used to disperse graphene and other 2D materials in a solvent called liquid-phase exfoliation. The process consists in breaking down the layers making up the original material, such as graphite in the case of graphene, using the surface tension properties of an appropriately selected solvent. The new feature of this discovery lies in the modification of the dispersion, after performing exfoliation, adding components that optimise it for ink jet printing. We have also added a special component which minimises the dispersion of the various materials when one is printed over the other. In fact the purpose of this process was to print films of different 2D materials one on top of the other, a little like building a tower of Lego bricks. And given that the various 2D materials have different electrical properties, they can be stacked in sequence to produce an electrical device. Nature is full of materials made up of layers, and graphene is simply the most famous 2D material in this case. In reality the range of 2D materials is vast, obtained by exfoliating the materials by the “layers” found either naturally or synthetically. One example is that of boron nitride, in a hexagonal form, and the entire family of “transition metal dichalchogenides”, such as MoS2 (molybdenum sulphide), WS2 (tungsten disulphide) etc. Boron nitride is an isolator, while the “transition metal dichalchogenides” are semi-conductors, unlike graphene, which is a semi-metal”.
As this technology is very flexible and involves low costs, researchers firmly believe that it can find widespread application in the smart packaging sector, as well as the biomedical sector, given the biocompatibility of the inks, thus opening up the gates to a major challenge.
Biography of Prof Cinzia Casiraghi
Cinzia Casiraghi graduated with honours in Nuclear Engineering in 2001 at the Politecnico of Milan. In 2006 she obtained her PhD in Electrical Engineering at Cambridge University with a project aimed at Raman characterisation and applications of thin films of disorderly carbon. After her PhD, Cinzia Casiraghi continued with her research at Cambridge for two years, where she started studying graphene. In 2008 she won a prestigious award (Sofja Kovalevskaja Award, from the Humboldt foundation), which enabled her to move to the Free University of Berlin, where she set up her own independent research group. In 2010 she obtained a permanent role as lecturer at the Chemistry faculty of Manchester University, where she continues to research graphene and other 2D materials. In 2016 she became full Professor.
For more details on the research group: http://casiraghi.weebly.com/