TECHNOLOGY FOR CHANGE

Foldable iPads, Solar Cells Made Possible by Copper Nanowires

Rebecca Kutzer-Rice | Date: 06-16-10 | Comments

Researchers at Duke University have developed a way to mass-produce nanowires from copper, a cheap and effective solution that could pave the way for bendable electronic displays and solar cells.

Although nanowires perform better than nanotubes, carbon nanotubes are still a go-to material for nanostructures, largely because of the expensive manufacturing costs of nanowires. Researchers at Duke University have developed a way to make nanowires out of copper, a material that is proving to be cheap but effective.

Currently, some of the best nanowires are constructed of silver and are small enough to be transparent. Transparency is a key factor because it enables the nanowires to be used in devices like solar cells, flat-screen TVs and computers, and flexible electronic displays. Because silver is so expensive, however, these devices instead often have transparent conductive layers made from indium tin oxide (ITO). But ITO also has crucial disadvantages, including brittleness, inefficiency and, because of increasing demand, expense.

"If we are going to have these ubiquitous electronics and solar cells," says Benjamin Wiley, an assistant professor of chemistry at Duke, "we need to use materials that are abundant in the Earth's crust and don't take much energy to extract."

Wiley and his colleagues may have found this ideal material in copper, an element that is transparent and conductive while still being cheap and incredibly abundant. While copper nanowires have been produced before, the Duke team has perfected a method of mass-manufacturing them. Such potential for quantity holds promise for commercial use.

Tiny copper nanowires like these may be the key to bendable electronic displays and solar cells. The inset shows CuNWs with spherical copper particles attached at one end (scale bar = 200 nm). (Source: Benjamin Wiley, Duke University)

"Imagine a foldable iPad," Wiley states. "We think that using a material that is a hundred times cheaper [than ITO] will be even more attractive to venture capitalists, electronic companies and solar companies who all need these transparent electrodes."

Bendable displays are not a new idea, but copper nanowires offer a way to revolutionize this innovation. The copper nanowires are created through the mechanism of crystal growth. In this process, scientists add chemicals to a water-based solution until the copper crystallizes and forms tiny �seeds,� from which the nanowires develop. This water-based process offers greater efficiency than ITO production methods.

Other researchers included Ph.D. candidate Aaron Rathmell and undergraduate Stephen Bergin. Wiley is currently seeking a patent on his design.