Ultra-thin smartphone touchscreens could be printed like a newspaper
Scientists in Australia have developed a new type of electronic material that is touch-responsive and just a fraction of the thickness of current smartphone screens. This could see it one day find use in next-generation mobile devices, and because of its incredible thinness and flexibility, could be manufactured at large scale using roll-to-roll (R2R) processing like a printed newspaper.
The breakthrough comes from researchers at RMIT University, who began with a material commonly used in today's mobile touchscreens called indium-tin oxide. This transparent material is highly conductive but does have its shortcomings, chiefly that it is very brittle, so the team sought to give it better pliability by greatly reducing its thickness.
“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 Dr Torben Daeneke. “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."
The researchers achieved this through what they call a liquid metal printing process. This involves heating an indium-tin alloy to 200° C (392° F) in order to make it a liquid, before rolling it across a surface to produce nano-thin sheets. These two-dimensional sheets are made from the same chemicals as regular indium-tin oxide, but internally feature a different crystal structure that affords them some unique capabilities.
While full flexibility is the material's flagship feature, it is also more transparent, absorbing just 0.7 percent of the light that hits it, compared to the five to 10 percent absorbed by standard conductive glass.
“This means a mobile phone with a touchscreen made of our material would use less power, extending the battery life by roughly 10 percent," says Daeneke.
As it stands, the team has built a working touchscreen with the material, but imagine its value could extend to other areas as well. LEDs, advanced touch displays, solar cells and smart windows are touted as other possibilities that have been opened up by this new fabrication technique.
“There’s no other way of making this fully flexible, conductive and transparent material aside from our new liquid metal method,” says Daeneke. “It was impossible up to now – people just assumed that it couldn’t be done.”
The team is now exploring commercial opportunities for the technology with hopes of attracting industry collaborators to help get it to market.
The research as been published in the journal Nature Electronics.