Silver Nanowires Show Promise for Next-Generation Touch-Screen Technologies

Traditional touchscreen material is unfit for use in flexible devices, and it is suffering from a supply shortfall.

Materials Today Communications and Scientific Reports paper has published a study that describes the ideality of using silver nanowires for flexible, touch-screen technologies while also probing into how the material can be adjusted to improve its overall performance. Presently, touch screen devices mainly depend on electrodes, which are made from indium tin oxide (ITO), a material that is expensive to source and process and very brittle.

Professor Alan Dalton from the University of Surrey along with his team and in association with M-SOLV, which is a touch-sensor manufacturer from Oxford, searched for an alternative material to resolve the drawbacks of ITO, as it is facing a supply shortfall. The other alternative materials that are being studied as ITO substitutes are carbon nanotubes, graphene, and arbitrary metal nanowire films. This research indicated how silver nanowire films have become a powerful contender, because of conductivities and transmittances that can match and surpass than those of ITO. This material contains wires that are a much thinner than a human hair, and form an interconnected conductive network.

Showcasing A New Process

Matthew Large described the significance of these new results in his recent study that was published in Scientific Reports.

Our research hasn’t just identified silver nanowires as a viable replacement touchscreen material, but has gone one step further in showing how a process called ‘ultrasonication’ can allow us to tailor performance capabilities. By applying high frequency sound energy to the material we can manipulate how long the nanosized ‘rods’ of silver are. This allows us to tune how transparent or how conductive our films are, which is vital for optimizing these materials for future technologies like flexible solar cells and roll-able electronic displays.

Matthew Large, First Author

In last month’s paper Materials Today Communications, the same research team, demonstrated how silver nanowires could be processed with the same laser ablation method, which is generally used for producing ITO devices. The team leveraged this method to create a fully operating five inch multi-touch sensor, similar to those utilized in smartphone technology. They found that this sensor used less energy but performed comparably to the sensor based on ITO.

Not only does this flexible material perform very well, we have shown that it is a viable alternative to ITO in practical devices. The fact we are able to produce devices using similar methods as currently in use, but in a less energy-intensive way is an exciting step towards flexible gadgets that do not just open the door for new applications, but do so in a much greener way.

Professor Alan Dalton, University of Surrey

An Easy Alternative

We are seeing a lot of interest from our customers in silver nanowire films as an ITO replacement in devices. This work is a really important step in establishing exactly which sensor designs can make good nanowire products. The fact that the nanowire films are processed by the same laser techniques as ITO makes the transition from ITO to nanowires really straightforward. It won’t be long before we are all using nanowires in our electronic devices.

Maria Cann, Technologist, M-SOLV

The team, currently based at the University of Sussex, are exploring new ways to increase the process scalability so that it becomes more industrially viable. One limitation is the current price of silver nanowires. The team is partnering with M-SOLV and Thomas Swan, a graphene supplier, to use a combination of graphene and nanowire in the electrodes to make it economically viable. This project is being funded by Innovate UK and EPSRC.