DURHAM, N.C. -- Copper nanowires may be coming to a little screen near you.
These new nanostructures have the potential to drive down the costs of displaying information on cell phones, e-readers and iPads, and they could also help engineers build foldable electronics and improved solar cells, according to new research.
Duke chemist Ben Wiley and his graduate student have developed a technique to organize copper atoms in water to form long, thin, non-clumped nanowires. The nanowires are then transformed into transparent, conductive films and coated onto glass or plastic.
The new research shows that the copper nanowire films have the same properties as those currently used in electronic devices and solar cells, but are less expensive to manufacture. The results were published online Sept. 23 in Advanced Materials.
The films that currently connect pixels in electronic screens are made of indium tin oxide, or ITO. It is highly transparent, which transmits the information well. But the ITO film must be deposited from a vapor in a process that is a thousand times slower than newspaper printing, and, once the ITO is in the device, it cracks easily. Indium is also an expensive rare earth element, costing as much as $800 per kilogram.
These problems have driven worldwide efforts to find less expensive materials that can be coated or printed like ink at much faster speeds to make low-cost, transparent conducting films, Wiley said.
One alternative to an ITO film is to use inks containing silver nanowires. The first cell phone with a screen made from silver nanowires will be on the market this year. But silver, like indium, is still relatively expensive at $1400 per kilogram.
Copper, on the other hand, is a thousand times more abundant than indium or silver, and about 100 times less expensive, costing only $9 per kilogram.
In 2010, Wiley and his graduate student Aaron Rathmell showed that it wa
|Contact: Ashley Yeager|