An international team of nano-materials researchers from the University of Illinois at Chicago and Korea University have produced an ultrathin film that is both transparent and highly conductive to electric current.
The film, actually a mat of tangled nanofiber, electroplated to form a "self-junctioned copper nano-chicken wire," is also bendable and stretchable, offering potential applications in roll-up touch screen displays, wearable electronics, flexible solar cells and electronic skin.
"It's important, but difficult, to make materials that are both transparent and conductive," says Alexander Yarin, one of the corresponding authors on the publication.
The new film establishes a "world-record combination of high transparency and low electrical resistance," the latter at least 10-fold greater than the previous existing record, said Sam Yoon, who is also a corresponding author and a professor of mechanical engineering at Korea University.
The film also retains its properties after repeated cycles of severe stretching or bending, Yarin said, an important property for touchscreens or wearables.
Manufacture begins by electrospinning a nanofibre mat of polyacrylonitrile, or PAN, whose fibers are about one-hundredth the diameter of a human hair. The fiber shoots out like a rapidly coiling noodle, which when deposited onto a surface intersects itself a million times, Yarin said.
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The electrospinning and electroplating are both relatively high-throughout, commercially viable processes that take only a few seconds each, according to the researchers.
The study has been published in Advanced Materials.