Printable Nano-Thin Flexible Electronic Material for Future Touchscreen Devices

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Researchers from Australia's RMIT University have developed an ultra-thin and ultra-flexible electronic material that could be printed and rolled out like a newspaper, for the touchscreens of the future. Its touch-responsive technology is 100 times thinner than existing touchscreen materials. To create the new conductive sheet, the team used a thin film common in mobile phone touchscreens and shrunk it from 3D to 2D, using liquid metal chemistry. 

The nano-thin sheets are readily compatible with existing electronic technologies and because of their incredible flexibility, could potentially be manufactured through roll-to-roll (R2R) processing just like a newspaper. The research, with collaborators from UNSW, Monash University and the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), is published in the journal Nature Electronics.

According to lead researcher Dr. Torben Daeneke, an Australian Research Council DECRA Fellow at RMIT, most of the current-gen mobile phone touchscreens are made of a transparent material, indium-tin-oxide, which is very conductive but also very brittle. Thus in their research the team has taken an old material and transformed it from the inside to create a new version that is supremely thin and flexible. It can be bended, twisted, and could be made far more cheaply and efficiently than the slow and expensive way that is currently being used to manufacture touchscreens. Turning it two-dimensional also makes it more transparent, so it lets through more light. This means a mobile phone with a touchscreen made of this material would use less power, extending the battery life by roughly 10%.

Turning an Old Material into New

To create a new type of atomically-thin indium-tin-oxide (ITO), the researchers used a liquid metal printing approach. An indium-tin alloy is heated to 200C, where it becomes liquid, and then rolled over a surface to print off nano-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 exciting new mechanical and optical properties. As well as being fully flexible, the new type of ITO absorbs just 0.7% of light, compared with the 5-10% of standard conductive glass. To make it more electronically conductive, you just add more layers.

Dr. Torben Daeneke said that it’s a pioneering approach that cracked a challenge that was considered unsolvable. There’s no other way of making this fully flexible, conductive and transparent material aside from their new liquid metal method.

Bringing the Tech to Market

The research team has now used the new material to create a working touchscreen, as a proof-of-concept, and have applied for a patent for the technology. The material could also be used in many other optoelectronic applications, such as LEDs and touch displays, as well as potentially in future solar cells and smart windows.

The researchers received supports from RMIT Microscopy and Microanalysis Facility (RMMF) and MicroNano Research Facility (MNRF), the National Computational Infrastructure National Facility, the Pawsey Supercomputer Centre and the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF).

Click here to read the published paper.