撰文者： 塑膠智庫 | 出刊日期：2023-05-12 |
Printed electronics have evolved significantly over the last years, with researchers creating new flat and flexible designs for electronic components, such as circuits, for the electronic-device form factors of the future.
Now a team at RMIT University has d an ultra-thin and highly flexible material that can be printed and rolled out like newspaper. The researchers—who collaborated with other scientists at the University of New South Wales, Monash University and the ARC Centre of Excellence in Future Low-Energy Electronics Technologies—believe the material can be used to develop future touchscreen technologies.
“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,” said lead researcher Torben Daeneke, an Australian Research Council fellow at RMIT.
Previously, most mobile phone touchscreens were made of a transparent material, indium-tin oxide (ITO), which is highly conductive but also quite brittle. Daeneke’s team has repurposed this material using a liquid metal chemistry to shrink it from 3D to 2D, a process that also added a capacity for the material to bend, he said. “We’ve taken an old material and transformed it from the inside to a new version that’s supremely thin and flexible,” said Daeneke.
To the new atomically-thin ITO used in the novel material, the researchers heated an indium-tin alloy to 200 Celsius; at this temperature, it becomes a liquid. Then they rolled the material over a surface to print off nano-thin sheets of indium tin oxide.
These 2D nano-sheets have the same chemical composition as standard ITO but a different crystal structure, which gives them new mechanical and optical properties that researchers found well-suited to their work.
In addition to being fully flexible, the new type of ITO absorbs just 0.7 percent of light, compared with the 5 percent to 10 percent of standard conductive glass. If scientists want to make it more electronically conductive, they can just add layers to the material.
The ultimate result is a new touch-responsive technology that’s 100 times thinner than existing touchscreen materials and so pliable it can be rolled up like a tube for potential manufacturing through the same type of roll-to-roll (R2R) processing used to print newspapers.
Transparency Saves Energy
The added benefit of allowing more light to pass through and thus becoming more transparent means touchscreens being made from the material would require less electrical energy, Daeneke noted. “This means a mobile phone with a touchscreen made of our material would use less power, extending the battery life by roughly 10.”
Researchers published a paper on their work in the journal Nature Electronics.
They’ve already used the new material to a working touchscreen as a proof-of-concept, and also applied for a patent for the technology. In addition to touchscreens, other optoelectronic applications for the material include LEDs and touch displays, as well future solar cells and smart windows.
Researchers have developed an ultra-thin, ultra-flexible, transparent electronic material that can be printed and rolled out like newspaper for touchscreens of the future. This touch-responsive technology is 100 times thinner than existing touchscreen materials and so pliable it can be rolled up like a tube.
To the new conductive sheet, a team led by researchers at RMIT University in Australia took a thin film of indium-tin oxide (ITO), a transparent material commonly used in cell phone touchscreens, and shrunk it from three dimensions to two dimensions 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, which involved collaborators from the University of New South Wales (UNSW), Monash University and the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), all in Australia, is reported in a paper in Nature Electronics.
According to lead researcher Torben Daeneke, a research fellow at RMIT University, while ITO is transparent and very conductive, it is also very brittle. ′We′ve taken an old material and transformed it from the inside to a new version that′s supremely thin and flexible,′ he said.
′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. Turning it two-dimensional (2D) 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%.′
The current way of manufacturing ITO for use 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 specialized equipment – it could even be done in a home kitchen,′ Daeneke said. ′We′ve shown it’s possible to printable, cheaper electronics using ingredients you could buy from a hardware store, printing onto plastics to make touchscreens of the future.′
To this new type of atomically thin ITO, the researchers used a liquid metal printing approach. This involves heating an indium-tin alloy to 200°C, where it becomes liquid, and then rolling it over a surface to print off nano-thin sheets. These 2D nano-sheets have the same chemical composition 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 5–10% for standard conductive glass. To make it more electronically conductive, you just add more layers.
According to Daeneke, it′s a pioneering approach that overcomes a challenge once considered unsolvable. ′There′s no other way of making this fully flexible, conductive and transparent material aside from our new liquid metal method,′ he said. ′It was impossible up to now – people just assumed that it couldn′t be done.′
The research team have already used the new ITO material to a working touchscreen, as a proof-of-concept, and have applied for a patent on 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,′ Daeneke said.