Inkjet-Printed Graphene Circuits: How to Create Foldable, Pocket-Sized Computers

We may be one step closer to creating foldable computers that could potentially fit in a pocket. Researchers have created a graphene-based ink that's highly conductive and tolerant to bending. They then used it to inkjet-print graphene patterns that could eventually be used to create extremely detailed, conductive electrodes.

Graphene is the new wonder material of the technological world. It was first discovered in 2004 and holds plenty of promise for the future. The world's thinnest, strongest and most conductive material, it could potentially be used in computer chips, broadband connections and could help with drug delivery, according to Red Orbit.

It's actually historically produced through mechanical exfoliation, which essentially means "peeling off layers of graphite using sticky tape," according to Extreme Tech. This, in turn, produces high-quality graphene. Unfortunately, the process is time consuming and researchers have yet to figure out a way to scale up the process for mass production.

Even so, graphene is an extremely promising substance when it comes to electronics. Inkjet printing has actually previously been explored as a method for fabricating transistors, solar cells and other electronic components. It's inexpensive, capable of printing large areas and can create patterns on a variety of substrates. This makes it an attractive option for next-generation electronics.

"Graphene has a unique combination of properties that is ideal for next-generation electronics, including high electrical conductivity, mechanical flexibility and chemical stability," said Mark Hersam, professor of materials science and engineering at Northwestern's McCormick School of Engineering and Applied Science. "By forumulating an inkjet-printable ink based on graphene, we now have an inexpensive and scalable path for exploiting these properties in real-world technologies."

In order to create the graphene ink, researchers first developed a way to mass-produce graphene that maintained its conductivity. The method involves using ethanol and ethyl cellulose to exfoliate graphite. The relatively clean process actually minimizes residues and results in a powder with a high concentration of nanometer-sized graphene flakes, which is then mixed with a solvent to create the ink.

It was then time to put the new mixture to the test. The researchers printed the ink in multiple layers, each about 14 nanometers thick, in order to create precise patterns. They found that the ink's conductivity remained virtually unchanged, even when bent to a great degree. This unique property actually suggested that graphene inks could potentially be used to create foldable electronic devices in the future.

The findings are published in the Journal of Physical Chemistry Letters.