Imagine touchscreens so thin you can roll them and fold them

 Australian researchers hope their new material will open a world of possibilities.

RMIT University

By Nick Carne

Australian researchers say they have developed an ultra-thin, ultra-flexible electronic material that could be printed and rolled out much like an old-fashioned newspaper.

The touch-responsive technology is 100 times thinner than existing touchscreen materials and so pliable it can be rolled up like a tube, they report in a paper in the journal Nature Electronics.

To create it, a team led by RMIT University in Melbourne used a thin film common in mobile phone touchscreens and reduced it from 3D to 2D, using liquid metal chemistry.

The nano-thin sheets are readily compatible with existing electronic technologies, they say, and are so flexible they could potentially be manufactured through roll-to-roll (R2R) processing.

"We've taken an old material and transformed it from the inside to create a new version that's supremely thin and flexible," says lead researcher Torben Daeneke.

"You can bend it, you can twist it, and you could make it far more cheaply and efficiently that the slow and expensive way that we currently manufacture touchscreens.

"Turning it two-dimensional also makes it more transparent, so it lets through more light. This means a cell phone with a touchscreen made of our material would use less power, extending the battery life by roughly 10%."

Creating the new type of atomically-thin indium-tin oxide (ITO) doesn't require expensive or specialised equipment, Daeneke says. In fact, “it could even be done in a home kitchen".

An indium-tin alloy is heated to 200 degrees Celsius, becomes liquid, then is rolled over a surface to print off the very thin sheets of indium tin oxide.

These 2D nano-sheets have the same chemical make-up as standard ITO but a different crystal structure, giving them new mechanical and optical properties.

As well as being flexible, the material absorbs just 0.7% of light, compared with 5-10% for standard conductive glass. To make it more electronically conductive, add more layers.

"There's no other way of making this fully flexible, conductive and transparent material aside from our new liquid metal method," Daeneke says. "It was impossible up to now: people just assumed that it couldn't be done."

His team has created a working touchscreen as a proof-of-concept.

They suggest the material has potential in many optoelectronic applications, such as LEDs and touch displays, as well as in future solar cells and smart windows.

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