We’ve all been there—regretting a short moment of clumsiness as we stare solemnly into a cracked smartphone screen. Thankfully, those days may soon be over thanks to scientists at the University of Sussex.
The researchers created a cheaper, stronger, and eco-friendlier way to make smartphone touch screens. If that wasn’t enough, the team also stated devices will increase responsiveness, consume less energy, and won’t tarnish when exposed to air.
Currently, touch screens rely on indium tin oxide. This material is expensive, brittle, and isn’t the most environmentally conscious substance to extract. Silver presents a suitable substitute, but doesn’t cut down on cost.
Taking these facts into consideration, University of Sussex scientists decided to combine silver nanowires and graphene to create a new hybrid material. The result noticeably reduced expenses and sustained the same performance levels of existing devices.
“The addition of graphene to the silver nanowire network also increases its ability to conduct electricity by around a factor of ten thousand. This means we can use a fraction of the amount of silver to get the same, or better, performance. As a result, screens will be more responsive and use less power,” says Professor Alan Dalton from the School of Mathematical and Physical Sciences at the University of Sussex.
Not only was the combination of materials unique, but how the team placed down the graphene layer. First, the graphene particles floated on the water’s surface. Next, they were extracted using a rubber stamp. From there, the team could place the graphene particles in different patterns atop the silver nanowire film.
“And this breakthrough technique is inherently scalable. It would be relatively simple to combine silver nanowires and graphene in this way on a large scale using spraying machines and patterned rollers. This means that brittle mobile phone screens might soon be a thing of the past,” says Professor Dalton.
According to Dr. Matthew Large from the School of Mathematical and Physical Sciences at the University of Sussex, silver is similar to indium in that it’s also a rare metal. However, “the amount we need to coat a given area is very small when combined with graphene. Since graphene is produced from natural graphite—which is relatively abundant—the cost for making a touch sensor drops dramatically.”
The addition of graphene also prevents silver from tarnishing in air, according to Dr. Large.
“What we’ve also seen is that when we bend the hybrid films repeatedly the electrical properties don’t change, whereas you see a drift in the films without graphene that people have developed previously. This paves the way towards one day developing completely flexible devices,” Dr. Large adds.
The paper, “Selective mechanical transfer deposition of Langmuir graphene films for high-performance silver nanowire hybrid electrodes,” can be found in the American Chemical Society journal Langmuir.