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US researchers say inkjet-printed graphene could allow the production of foldable electronics with extremely detailed conductive electrodes.
By utilising their newly developed graphene-based ink, the Northwestern University researchers could produce patterns 250 times more conductive than previous attempts to print graphene-based electronic patterns.
According to the researchers, graphene’s high electrical conductivity, mechanical flexibility and chemical stability make it well-suited for next-generation electronics.
By combining the material with inkjet printing technology, the researchers say they have created an inexpensive and scalable path for exploiting those properties in real-world technologies. Inkjet printing allows printing over large areas, and can create patterns on a range of substrates.
Until now, inkjet printing with graphene has remained a challenge because rendering graphene into printable ink required processes like exfoliation or the use of solvents, which make the resulting material less conductive.
The Northwestern researchers developed a new method for mass-producing graphene that maintains its conductivity and can be carried out at room temperature using ethanol and ethyl cellulose to exfoliate graphite.
The process reduces residues, and the end result is a powder with a high concentration of nanometer-sized graphene flakes, which is then mixed into a solvent to create the ink.
The ink was demonstrated by printing 14nm thick layers on top of each other to create precise patterns. Conductivity is retained even when bent to a great degree.