Monday, August 8, 2016

Printing electronics like newspapers?

According to The Economist, yes.

Some of the fastest web-offset presses, in which an inked image is transferred to another roller and thence to the surface being printed, can churn out more than 20 newspapers a second. Flexographic presses, which use a flexible relief image on a cylinder to print things such as packaging, can belt along at 500 metres a minute. These methods have already been adapted to print basic electronic circuits, by replacing conventional graphic inks with conductive inks that can carry an electric current. Scientists and engineers, however, have loftier ambitions than these. They are developing ways to print not just circuits but also sophisticated electronic devices, such as thin-film transistors, using the mass-production capabilities of roll-to-roll processes.

. . .

Printing electronics requires special formulations of ink. Often, these are made with silver, which is a better conductor even than copper. But silver is expensive. An alternative, being worked on by Tawfique Hasan and his research group at Cambridge University, is to include flakes of graphene in such inks. Graphene is a form of carbon made from sheets a single atom thick. The result, Dr Hasan claims, can be manufactured and printed for a fraction of the cost of silver ink and is conductive enough for many applications, such as disposable biosensors used to test samples from patients, and packaging that can track and authenticate a product. Graphene ink could also be used to make electrodes for printed batteries.

Dr Hasan and his colleagues have demonstrated flexographic printing of conductive graphene ink at more than 100 metres a minute. They are working in collaboration with Novalia, a firm in Cambridge that has produced several printed touch-sensitive products, including a musical keyboard and interactive posters. They have also established a company called Inkling Cambridge to commercialise the formulation and develop other electronic inks, coatings and paints.

One idea they are exploring is “smart” wallpaper. In addition to graphene ink, this would use either organic light-emitting diodes (OLEDs) or quantum dots—crystals of semiconducting material just a few atoms across. Both of these emit light when excited by electricity, so wall coverings printed with such materials could be used to illuminate rooms.

. . .

Another use for printed electronics of this sort is solar energy. Several groups are working on making thin-film solar panels in this way. Such panels, being cheap and lightweight, could readily be attached to walls and roofs, and even built into roofing tiles.

There's more at the link.

Sounds very interesting - just as long as purchasers don't use old printed electronics to line the catbox or the bird cage!  I can foresee some interesting short-circuits . . .


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