New Electronic Labels Could Alert You When Your Milk Spoils

New 2D printed electronics made of the nanomaterial graphene could be used in newspapers, self-updating price tags and more

Dr Toby Hallam Prof Coleman and  PhD student Adam Kelly.jpg
Jonathan Coleman (center) and team show off a printed electronic label. Trinity

Some of the most delightful bits from the Harry Potter movies involve the front page of the Daily Prophet, the wizarding newspaper featuring photographs that move like gifs.

“In Harry Potter, that’s magic,” says Jonathan Coleman, a materials scientist at Trinity College Dublin. “But for us, that’s technology.”

Coleman and his team have created the first-ever printed transistors made entirely of 2D nanomaterials. In other words, they’ve made totally flat electronics that can potentially be printed extremely cheaply. These printed electronics could have any number of uses. They could, for example, be used to replace traditional price labels in a supermarket. Instead of having an employee with a label gun walking around changing prices, electronic labels could update themselves automatically. They could make passports that renew themselves, or wine bottles that tell you when they’re being stored at too warm a temperature. As in the Harry Potter scenario, they could be used to make moving newspapers, posters and book jackets.

Coleman sees this technology merging with the Internet of Things to make even the most ordinary items connected. Your carton of milk could now have internet connection through its label, speaking directly to your smartphone to tell you when it’s begun to run out or go bad. Your bedroom window could offer continuous weather updates.

“If you can print electronics very cheaply, you can imagine things that are almost unimaginable,” Coleman says.

Printed electronics have existed in some form for about 30 years. The advantage these new transistors hold over older printed electronics has to do with their building materials. While most printed electronics are made from polymers, this new invention is made out of graphene. Graphene, a much-buzzed-about nanomaterial, is a two-dimensional honeycomb lattice of carbon only one atom thick.  It’s strong, light and an extremely good conductor, plus—and perhaps most importantly—it’s cheap.

“It’s made from graphite and graphite’s just something that’s dug out of the ground,” Coleman says.

In addition to being cheaper, the new 2D printed electronics stand to be much better quality than current versions, says Coleman. Existing types have a number of performance limitations having to do with stability and energy conversion.

The transistors were printed using graphene nanosheets as electrodes, with tungsten diselenide and boron nitride (two other nanomaterials) as the other parts of the transistor. The nanomaterials are produced in liquid, a method developed by Coleman. The resulting nanosheets are flat and (relatively) wide, and can be conducting, insulating or semiconducting depending on the material.

The research was published this month in the journal Science

Coleman estimates it could be a decade or so before products incorporating this technology are good enough to make it to market. This is a relatively short timeline, he says, because there’s so much global interest in nanomaterials like graphene, and therefore so many scientists working to optimize products like these. His own research is part of the Graphene Flagship, a billion-euro EU-funded initiative to further graphene innovations with potential uses for the public.

“It’s within touching distance,” he says. “We know what needs to be done, it’s just a question of doing it, and the money is in place.”

The 2D printed electronics are only one potential use of nanomaterials like graphene. Other uses under investigation include extremely fast-charging batteries, sponges to clean up oil spills and solar panels that work even in the rain.

“Nanomaterials have a whole host of wonderful properties, which I firmly believe are going to change the world by allowing us to make things and applications better, faster and cheaper,” Coleman says. “We have a technological revolution coming down the track that we’re starting to see the first fruits of, and I think we’re going to see amazing things over the next decade or so.”

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