Experimental feature

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Experimental feature

What if, rather than ordering new business cards when you change jobs, you could just update your existing card directly? Or if you could dial up a new colour of wallpaper when you grew bored of the old?

Turning everyday paper products into interactive devices is becoming a possibility thanks to the work of Elvira Fortunato and her husband Rodrigo Martins, the Portuguese inventors of paper transistors. As the electronic book and online newspaper threaten to turn paper into mere packaging, their research promises a new future for a 2,000-year-old material.

A director of the Materials Research Centre (Cenimat) at Lisbon’s Universidade Nova, Prof Fortunato began looking at paper as a support material for transistors, the “Lego bricks”, as she puts it, that provide the computing power in almost every electronic device.

Her breakthrough came with the discovery that paper could function in a transistor as an active component. “A transistor needs insulating, semi-conducting and conducting material to work,” she says. “Our innovation was to show that paper could provide the insulating component.”

Deploying zinc oxide, another cheap and abundant substance, as a semiconductor, and aluminium as the conductor, the team used photocopy paper and an adapted ink-jet printer to make its first transistor. “I thought the probability of success was very low, but it worked first time,” says Prof Fortunato.

Since publishing their results in 2008, the team has been working on potential industrial applications. It is now a candidate to run a €20m European pilot project to manufacture paper chips. “In two to four years, Europe could see the birth of an electronic paper industry,” says Prof Martins.

Their aim is develop low-cost, disposable applications to complement rather than replace silicon chips. The latter are more efficient, but also far more expensive and environmentally damaging to produce. Up to 80 per cent of naturally-occurring silicon is lost in the manufacture of chips, which requires high temperatures, clean rooms and the use of toxic gases.

Paper microchips, by contrast, can almost be made at home, says Prof Fortunato. They use about 1,000 times less material, can be produced at room temperature at a fraction of the cost and are entirely recyclable and disposable.

Intelligent labels, including interactive shipping tags and remotely updateable supermarket labels, are high on the list of potential uses, along with self-updating plane tickets, business cards and food labels. Worried that an elderly relative may have forgotten to take their medication? Packets of tablets could soon alert you by electronic message.

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