(via Duke University & ACS Publications)
The uses of digital screens on hand held devices are rapidly expanding. An elemental part of this industry is its use of indium tin oxide (ITO), which is part of the transparent coating to create the displays we use on our cell phones, iPads and devices alike. But there is a draw back to using ITO in millions of devices. ITO is obtained from a slow expensive process which gives it a cost of $600-$800 per kilogram.
However, the tide may soon be changing for a big part of this industry. In a paper published May 29 by Duke University’s assistant chemistry professor Benjamin Wiley, titled NanoLetters, he explains a new method for synthesizing a nano wire material made of copper and nickel. He also tells of its properties that could very well be used to replace the expensive ITO found in everyday devices. The cupronickel wires could also be used as a new medium for printed circuit boards. It could be used in electronic paper displays, flexible clothing, packaging, solar cells and LEDs as well.
Copper nanowires alone were undesirable because of their natural orange tint and corrosiveness. The team hypothesized that coating the copper nanowires with nickel solve the issue of the orange tint and also protect the copper from corrosion. After experimentation, their hypothesis was confirmed.
The thin film of conductive cupronickel nanowires is composed of a 2:1 ratio of copper to nickel and has a grayish tint which works fine in displays and electrochromic windows. The nanowires themselves are only about 70 nm wide. In the paper published, the Duke team speaks of the method for synthesizing and new information about the properties of the material like higher strength and flexibility. It is projected that a cupronickel film containing 20-mol % nickel will lose half of its conductivity in 400 years at room temperature. By comparison, nano films of pure copper or silver lose half their conductivity in only 3 and 36 months, respectively, at room temperature.
Of course, there are limitations this new material. This cupronickel material cannot be used in LCD screens the way it is because it is not as conductive as ITO, and high electrical conductivity is needed when viewing films with a high level of transparency.
Still, this is only the beginning and researchers at Duke are excited about their results because it means that many products can use this new material and use elements that are much more abundant and easily obtained. Whether the decrease in manufacturing cost will transfer to a price drop of devices, will be left to the capitalists.