Australian scientists have achieved what was previously thought impossible, creating a 'nano-thin', ultra-flexible and printable touchscreen that could be the future of smartphones.
The new material was developed by researchers from RMIT, UNSW and Monash University, and is so pliable it can be printed and rolled up like a newspaper.
The touch-responsive technology is 100 times thinner than existing touchscreen materials, the researchers revealed in a paper published in the journal Nature Electronics last week.
How an 'impossible' problem was solved
Traditionally, mobile phone touchscreens have been made of a transparent material called indium tin oxide (ITO) which is very conductive, but also very brittle.
To create a new type of atomically-thin ITO that is both conductive and pliable, the researchers shrunk the material from 3D to 2D using liquid metal chemistry.
They heated indium tin alloy to 200C (the temperature at which it becomes liquid) and then rolled it over a surface to print 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.
“We’ve taken an old material and transformed it from the inside to create a new version that’s supremely thin and flexible,” said lead researcher Torben Daeneke, an Australian Research Council DECRA Fellow at RMIT.
As well as being fully flexible, the new type of ITO absorbs just 0.7 per cent of light, compared with the 5 to 10 per cent of standard conductive glass.
More layers can be added to make it more electronically conductive.
The researchers' pioneering approach has solved what was previously considered an impossible problem.
“There’s no other way of making this fully flexible, conductive and transparent material aside from our new liquid metal method,” Dr Daeneke said.
It was impossible up to now – people just assumed that it couldn’t be done.”
Cheaper, more efficient, and saves battery
The new material is cheaper and more efficient to manufacture, and would help to extend smartphone battery life.
The current method of manufacturing the transparent film used in standard touchscreens is a slow, energy-intensive and expensive batch process, conducted in a vacuum chamber.
The beauty is that our approach doesn’t require expensive or specialised equipment – it could even be done in a home kitchen,” Dr Daeneke said.
“We’ve shown it's possible to create printable, cheaper electronics using ingredients you could buy from a hardware store, printing onto plastics to make touchscreens of the future.”
The nano-thin sheets are readily compatible with existing electronic technologies and their incredible flexibility means they could potentially be manufactured through roll-to-roll processing just like a newspaper.
You can bend it, you can twist it, and you could make it far more cheaply and efficiently than the slow and expensive way that we currently manufacture touchscreens,’’ Dr Daeneke said.
Transforming ITO from a three-dimensional to two-dimensional material also makes it more transparent, so it lets through more light, he said.
“This means a mobile phone with a touchscreen made of our material would use less power, extending the battery life by roughly 10 per cent."
The research team has used the material to create a working touchscreen, as a proof of concept, and has 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.
“We’re excited to be at the stage now where we can explore commercial collaboration opportunities and work with the relevant industries to bring this technology to market,” Dr Daeneke said.