Printing Graphene Electronics

Inkjet technology took the world by storm. First of all, there was digital image printing, which has improved its speed and has become more flexible than anybody ever thought possible (although it’s not really cheaper).

After that, 3D printing, where a layer of material is printed on top of another to produce three dimensional objects, came along. That technology has become the standard in producing complex prototypes.

Then there are the scientific research groups that have added conducting polymers to the inks and used them to print circuits onto flexible substrates. These polymers are being used to produce things like digital paper and disposable RFID tags. The polymers can be printed onto sheets of almost any size, unlike typical high-efficient circuitry which has to be created under extreme circumstances inside expensive fabrication plants.

University of Cambridge Researchers

There is a particular problem however, Inkjet-printed electronics don’t perform as well as traditional integrated circuitry by a very large margin – printed thin film transistors are just larger and less-efficient than silicon-based models. So there’s a battle raging to improve performance.

Recently, Andrea Ferrari and peers at the University of Cambridge in the UK demonstrated a giant leap forward. These researchers have found a way to switch out or complement the conducting polymers in these inks with graphene, the “magic” material of the technological realm right now.

It’s not very difficult to see why. The electronic properties of graphene are tough to best and make it the perfect candidate for nanoelectronics. But the hard part comes in trying to mix it with an ink that always produces small droplets – an aspect that obviously fundamental for inkjet printing.

This is basically what Ferrari and team have managed to do. They’ve discovered a way to easily produce graphene by chemically chipping flakes off a block of graphite and filtering them to remove any that might clog the printer heads.

Ferrari and peers then take the flakes and throw them into a solvent called N-Methylpyrrolidone, or NMP as it’s called, which reduces problems like the coffee ring effect that can happen when some of the solvents evaporate.

Eventually, they put the mixture into their printers and printed out a couple of circuits and thin film transisters.

Future Results

The results look terrific. The graphene-based inks either match or beat most of the other inks found on the market today. The results are especially promising because this was just a first-round experiment and we can be sure that improvements will soon follow. Who knows how far the technology could advance in even a year’s time?

"This paves the way to all-printed, flexible and transparent graphene devices on arbitrary substrates.," note Ferrari and peers in wrapping up their paper. This means that their research has just begun. I’m sure that we will certainly hear much more from these amazing scientists in the months and years to come.

Graphene itself is the “baby” of the scientific and technological realms right now because of its amazing applications. Without this material, none of these advancements would be possible.

technology review Photo by : University of Cambridge