Researchers at ETH Zurich have used a 3D print technology called Nanodrip to create a new type of transparent electrode, which takes the form of a grid made of gold or silver ‘nanowalls’ on a glass surface.
The electrode is to have a higher conductivity and to be more transparent than those made of indium tin oxide, the material currently used in smartphones and tablets. The team says the more transparent the electrode, the better the screen quality and the higher the conductivity, the more quickly and precisely the touchscreen will work.
In order to produce more conductive electrodes, the ETH team opted for gold and silver, but because these metals are not transparent, the scientists had to make use of the third dimension. According to ETH Professor Dimos Poulikakos: “If you want to achieve high conductivity and transparency in wires made from these metals, you have a conflict of objectives. As the cross-sectional area of gold and silver wires grows, the conductivity increases, but the grid's transparency decreases.”
The solution was to use metal walls less than 500nm thick. Because they are two to four times taller than they are wide, conductivity is sufficiently high.
The next challenge will be to develop the print process so that it can be implemented on an industrial scale. To achieve this, the scientists are working with colleagues from ETH spin off Scrona.