Graphene Ink Printing of Electronic Components November 25, 2011Posted by stuffilikenet in 3D Printing, Awesome, Science, Toys.
Using ink-jet printer nozzles for any number of fine fabrication techniques is already underway and under research, but Professor of Nanotechnology Andrea Ferrari and colleagues from the Engineering Department at the University of Cambridge have developed a method of creating a graphene ink that can be used with a modified ink-jet printer. This is revolutionary for two reasons: first, electronic components such as thin film transistors (TFTs) can already be created using ink-jet printing with ferroelectric polymer inks, but the performance of such components is poor and they are too slow for many applications. Graphene-enhanced versions of these transistors are much, much faster and have higher electron motilities. Second, the resulting components can be transparently printed on a number of flexible substrates. Essentially, the moving, flexible folding newspaper from Harry Potter films (and any number of science fiction stories) can be fabricated with a system of these graphene-ink-printed components.
Using flakes of pure graphite, the team peeled off layers of graphene using liquid-phase exfoliation (sonication of the graphite in the presence of a solvent). The graphene bits were ultra-centrifuged and filtered to remove any particles large enough to block the ink-jet printer heads (about a micron). These processed graphene bits were then used as the basis for the ink printed, using a more-or-less standard ink-jet printer, onto silicon and glass. They heated the substrates to drive off the ink carrier, leaving the graphene flakes behind. The results are at least comparable to current ferroelectric polymer inks:
“They achieved mobilities of up to around 95cm2V−1s−1, about 80% transmittance and 30kohm sheet resistance. Non-graphene polymer inks typically achieve mobilities of less than 0.5cm2V−1s−1, while adding carbon nanotubes can increase this to around 50cm2V−1s−1.”
The results should only improve as the method is refined and enhanced. I imagine that any number of display manufacturers would be interested in this method, if only to print touchscreens directly on their current displays cheaply.
I predict a burgeoning movement among the various hobbyists who specialize in printer hacks a la RepRap. People like Jeri Ellsworth have been working on home-made electronics (specifically in her case transistors) and will be very, very interested in what sounds like an easily-reproduced inkjet solution for printing small electronic components.
Ink-Jet Printed Graphene Electronics, F. Torrisi, T. Hasan, W. Wu, Z. Sun, A. Lombardo, T. Kulmala, G. W. Hshieh, S. J. Jung, F. Bonaccorso, P. J. Paul, D. P. Chu, A. C. Ferrari arXiv:1111.4970v1