Sussex Physicists Develop New Touchscreen Technology

The next generation of touchscreen technology that uses nano technology.

The most critical part of a smart device’s user experience, the touchscreen is sitting at the cusp of it’s next major evolution.

Collaborating with M-SOLV Ltd, a touch-sensor manufacturer based out of Oxford, England, Professor Alan Dalton (Sussex Professor of Experimental Physics) and his team have shown that silver nanowires that are more than a thousand times thinner than a human hair, are a viable alternative to the ITO, the material currently in touch screens. Indium tin oxide (ITO) is expensive to source, expensive to process and, as anyone who has dropped their smartphone will know — very brittle!

The team’s research will prove invaluable in determining alternatives to the materials used in the touchscreen technology today.

Professor Alan Dalton and his team have shown that not only are silver nanowires suitable for touchscreens, they also have the ability to produce extremely small patterns (pixels), small enough for high definition LCD displays, such as smartphones and the next generation of televisions and computer screens.

Published in journals Materials Today Communications and Scientific Reports, the paper titled Finite-size Scaling In Silver Nanowire Films: Design Considerations For Practical Devices investigates some of the intricacies of patterning silver nanowire films to produce detailed electrode structures, and also tries to tackle the monopoly of ITO (which is mined largely in China and Canada) and suffers from supply uncertainty.

Talking about his research, Professor Dalton quipped — ‘Display technologies such as LCD and OLED form images using pixels. Each pixel of these displays is further broken down into subpixels; typically, one each for red, green and blue color.
In the display in a smartphone these subpixels are less than a sixth of the width of a human hair — which is also similar in length to the silver nanowires used in our research.’

Dr. Matthew Large, the lead author of the paper, expanded — ‘In this research, we have applied a mathematical technique to work out the smallest subpixel size we can make without affecting the properties of our nanowire electrodes. This method was originally developed to describe how phase changes like freezing happen in very small spaces, The results tell us how to tune our nanowires to meet the requirements of any given application.’

In collaboration with their industrial partners, M-SOLV, the team is now looking to apply these to commercial projects and have demonstrated that the incorporation of silver nanowires into a multi-touch sensor actually reduces the production cost and energy usage.

Using a technique, called ‘ablation’, which involves the removal of material using a laser beam to produce individual electrode patterns, the team produced a fully operating five-inch multi-touch sensor, identical to those used in smartphone technology. They found it performed comparably to one based on ITO but used significantly less energy to produce.
Professor Dalton said: ‘Silver nanowire and silver nanowire/graphene hybrids are probably the most viable alternatives to existing technologies. Others scientists have studied several alternative materials, but the main issue is that the majority of other materials do not effectively compete with ITO or they are too costly to produce, at least at the moment.’

One limiting factor is the current cost of silver nanowires. To that end, the team is collaborating with a graphene supplier, Thomas Swan, to use a nanowire and graphene combination in the electrodes to markedly reduce cost.

The research might be still in stages of infancy, but it still has the potential to provide cheaper alternatives to the rest of the world. And that’s important, given that mundane everyday devices like watches, Wi-Fi routers and even fridges today carry touchscreens. Costs and energy consumption are important considerations for the future of all things smart.

Something this intrinsic would even affect the future of IoT — positively or negatively (no pun intended).

Originally published at Chip-Monks.