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New copper development may lead to lower tech prices

Copper might soon save cell phone screens from cracking in traumatic falls.

Benjamin Wiley, assistant professor of chemistry, and his research team have developed a new conductive film that could lead to flexible solar panels and cheaper screens in devices such as cell phones, e-readers and iPads, according to a study published in the journal Advanced Materials Sept. 23.

Wiley and graduate student Aaron Rathmell have developed a procedure that transforms copper atoms in solution into long, thin nanowires. These nanowires are used to create conductive films, which are an integral part of solar cells and electronic displays. Copper-based films are far more flexible, which makes technology more durable, as well as easier and cheaper to produce than the current industry standard, Wiley said.

“Imagine having solar curtains that could easily collapse and stretch out to collect electricity from the sun,” he said. “Or cell phone screens that wouldn’t crack when you drop them.”

Conductive films in screens and other applications are typically made of indium tin oxide—also known as ITO—a substance which is 100 times as expensive and 1,000 times as scarce as copper, Wiley said. Screens made from copper-based conductive films would also be extremely flexible.

“Half the time, the signature pad at the grocery store checkout doesn’t work because people have used actual sharp pens on it, causing the brittle screen to crack,” Wiley said. “If you had a screen that was flexible, you wouldn’t care what people used—you could use a toothpick.”

Creating copper-based films would also be much faster than manufacturing indium tin oxide-based films, which requires vaporized ITO to slowly coat a glass or plastic surface, Wiley said.

“We developed a transparent coating ink that we can literally paint down on a surface that will give us a transparent conducting film,” Wiley said. “It’s reasonable to expect it to be one to two orders of magnitude faster.”

To manufacture and market these copper-based films for commercial purposes, Wiley co-founded NanoForge in 2010. The company was granted $45,000 earlier this year by the North Carolina Innovative Development for Economic Advancement program, a non-profit which assists tech start-ups.

“We have been in full production since July,” said NanoForge CEO Steven Warwick, who received his MBA from the Fuqua School of Business in 2008. “The grant helped commercialize the technology and make it viable.”

Warwick, who co-founded NanoForge with Wiley, added that the company is planning to incorporate this technology into new applications, such as flat panel displays, touch panels and electromagnetic shielding. He noted that the copper-based films may not immediately supplant the widespread use of ITO but that they would eventually develop a significant hold in the technological market.

Wiley also noted the potential copper nanowires pose for cheaper solar technology.

“[Copper-based films] could potentially lower the cost of thin film solar cells and make them more competitive with fossil fuels,” he said.

Christopher Wedding, a lecturing fellow at the Nicholas School of the Environment, noted that decreased prices in solar panels will become more significant over time.

“The total cost of the panels is going to be increasingly important as the state and federal incentives dry up,” he said. “We’re already seeing that happen.”

Wedding noted, however, that many factors contribute to solar panel pricing and that it would be difficult to predict large changes to the market based on this particular technology.

Wiley said that disadvantages of the new copper film include its reddish color, which affects displays, and its slight tendency to oxidize. He plans to research copper alloys that would make the films gray in color and more resistant to oxidation.

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