Copper-nickel nanowires suitable for printed electronics
30 May 2012
Duke University chemists have created a new set of flexible, electrically conductive nanowires
Films made with copper-nickel nanowires are stable and relatively inexpensive to create, and so are an attractive option to use in printed electronics.
But one issue with pure copper nanowire films is that they have an orange tint that would be unacceptable in a display screen
Benjamin Wiley, an assistant professor of chemistry at Duke, noticed that unlike copper, nickels rarely turn green.
Inspired by the US five-cent piece, Wiley wondered if he could prevent oxidation of the copper nanowires by adding nickel.
This, he believed, would widen the application of these nanowires to include printed electronics.
He developed a method of mixing nickel into the copper nanowires by heating them in a nickel salt solution.
“Within a few minutes, the nanowires became much more grey in colour,” Wiley said.
Wiley then baked the new nanowires at various temperatures to test how long they conducted electricity and resisted oxidation.
The tests show that the copper-nickel nanowire films would have to sit in air at room temperature for 400 years before losing 50 percent of their electrical conductivity.
Silver nanowires would lose half of their conductivity in 36 months under the same conditions. Plain copper nanowires would last only 3 months.
While the copper-nickel nanowires stack up against silver and copper alone, they aren’t going to replace indium-tin-oxide in flat-panel displays any time soon.
“Instead, we’re currently focusing on applications where ITO can’t go, like printed electronics,” he said.
