Electronics

The paper is the circuit: Scientists create graphite-based paper circuitry

A flexible polymer circuit, shown here, could someday be replaced by a cheap and flexible paper circuit (Photo: Grant Hutchinson)
A flexible polymer circuit, shown here, could someday be replaced by a cheap and flexible paper circuit (Photo: Grant Hutchinson)
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A flexible polymer circuit, shown here, could someday be replaced by a cheap and flexible paper circuit (Photo: Grant Hutchinson)
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A flexible polymer circuit, shown here, could someday be replaced by a cheap and flexible paper circuit (Photo: Grant Hutchinson)
Treated with iron nitrate and heat, this everyday origami crane becomes conducting crane
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Treated with iron nitrate and heat, this everyday origami crane becomes conducting crane
The Max Planck logo is printed with catalyst, heated, then electroplated to prove its conductive properties
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The Max Planck logo is printed with catalyst, heated, then electroplated to prove its conductive properties

Given the low costs and extensive applications that could be possible with flexible paper circuit boards, we've seen many ideas for their production, from printing with silver ink to embedding chips within paper. Now, however, scientists have developed an elegant method for selectively changing the very nature of the paper itself into conductive graphite. Unlike polymer-based flexible circuits, these paper circuits are, ironically, able to withstand the high temperatures generally used in the production of electronics.

Using an ordinary inkjet printer loaded with a cartridge of an iron nitrate catalyst, the team at Germany's Max Planck Institute prints their target designs onto ordinary paper. When the paper is heated to 800°C (1,472°F) in an oxygen-free environment (which is presumably why the paper doesn't burn), the catalyst changes the composition of the paper's cellulose fibers into pure conductive graphite, while the unprinted paper remains unchanged.

The scientists proved that the resulting "carbon electronics" were selectively conductive by electroplating the paper with copper. As shown in the image below, only the printed design became copper-coated. They also demonstrated how to create a 3D conductive structure by subjecting, whimsically, an origami paper crane to the same catalytic process.

The Max Planck logo is printed with catalyst, heated, then electroplated to prove its conductive properties
The Max Planck logo is printed with catalyst, heated, then electroplated to prove its conductive properties

The mechanism of creating graphite from cellulose is still not fully understood, though iron is already also used in the manufacturing of carbon nanotubes. More experimentation and a better understanding could potentially lead to transforming paper-based structures into the atom-thick wonder nanomaterial, graphene.

Source: Max Planck Institute

7 comments
Slowburn
Why not just draw on the paper with a soft pencil?
Jerry Rotondaro
This changes everything...
jochair
@slowburn. the circuit is multilayer, using very thin paper.
William Carr
"Why not just draw on the paper with a soft pencil? Slowburn" Because Graphite is not Graphene. Although. It occurs to me that ... Google search. http://www.fastcodesign.com/1671917/watch-2-scientists-accidentally-discover-a-world-changing-super-material Ah. Yup. What occurred to me was that a layer of graphite exposed to a laser could BECOME Graphene. It's good to be right once in a while... Combining techniques would allow printing the graphite-oxide ink onto paper, shielding it from oxygen with a nitrogen gas flush, and zapping it with the laser. Then... do it again ! Build 3D circuits of graphene, a nonconductive layer of paper, and graphene again. Use silver conductive ink or the laser again to link the circuits as you grow them. Carbon nanotubes infused with silver? Imagine holding in your hand a 1" cube of graphene circuitry, as much processing power as a supercomputer.
William Carr
"Why not just draw on the paper with a soft pencil? Slowburn" Because Graphite is not Graphene. Although. It occurs to me that ... Google search. http://www.fastcodesign.com/1671917/watch-2-scientists-accidentally-discover-a-world-changing-super-material Ah. Yup. What occurred to me was that a layer of graphite exposed to a laser could BECOME Graphene. It's good to be right once in a while... Combining techniques would allow printing the graphite-oxide ink onto paper, shielding it from oxygen with a nitrogen gas flush, and zapping it with the laser. Then... do it again ! Build 3D circuits of graphene, a nonconductive layer of paper, and graphene again. Use silver conductive ink or the laser again to link the circuits as you grow them. Carbon nanotubes infused with silver? Imagine holding in your hand a 1" cube of graphene circuitry, as much processing power as a supercomputer.
Mark Keller
Brilliant Willam Carr!
Kwazai
When does that 'special' laserjet4 cartridge become available to the general public?