Silver nanowires are being used to create touchscreens with greater flexibility, paving the way for foldable screens.
Currently, touchscreen devices mainly rely on electrodes made from indium tin oxide (ITO), a material that is expensive to source, expensive to process and very brittle.
A team from the University of Surrey has been looking at alternative materials to overcome the some of the problems associated with ITO, which is currently suffering from supply uncertainty.
Alternative materials investigated as ITO replacements have included graphene, carbon nanotubes and random metal nanowire films.
But the new study shows how silver nanowire films have emerged as the strongest competitor, thanks to transmittances and conductivities that can match and readily exceed those of ITO.
This is a material that consists of wires which are over a thousand times thinner than a human hair, forming form an interconnected conductive network.
Matthew Large, who worked on the project, said: “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 optimising these materials for future technologies like flexible solar cells and rollable electronic displays.”
The silver nanowires can be processed to form a touchscreen mesh using the same laser ablation process already used for ITO.
Using this technique, the team produced a fully operating five inch multi-touch sensor, identical to those typically used in smartphone technology.
They found it performed comparably to ITO touchscreens while using significantly less energy to produce.
“Not only does this flexible material perform very well, we have shown that it is a viable alternative to ITO in practical devices,” said Professor Alan Dalton from the University of Surrey.
“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.”
The team is now looking to develop the scalability of the process to make it more industrially viable.
Silver nanowires are currently quite expensive to produce but it is believed that a nanowire and graphene combination could reduce the cost significantly.
LG demonstrated a flexible 18 inch organic light-emitting diode (OLED) display at CES in January that can be rolled into a tube like a newspaper.