If cheaper materials could be used to make the unseen components inside of your favorite consumer electronics work, would you settle for them if they functioned just as well (or even better)? If it makes you feel any better, you could still bling up your electronics for ridiculous prices so they’ll still look “better” than everyone else’s. Finding replacements for ITO (indium tin oxide) and other rare earth elements used for electronics has been an industry goal for quite some time. Granted, it’s not so much because manufacturers want to pass the savings along to consumers, but because rare earth elements are, as the name might hint, hard to come by and finite in supply. And when this supply is demanded, countries that produce it have the power to name its price or cut it off — not such a comfortable position for those who require it to keep production going.
ITO is currently used to make transparent film for connecting pixels in electronic screens (for cell phones, e-readers, and iPads); it is excellent for transmitting information, but it’s fragile and costs up to $800 per kilogram. Inks with silver nanowires have been used as an alternative, but silver is $1400 per kilogram — even if less quantity is required, it’s still a pretty hefty price tag. But Duke University chemist Ben Wiley and graduate student Aaron Rathmell have figured out a way to make copper nanowires serve the same purpose. Being a far more abundant resource available from a greater diversity of sources, copper is a comparatively bargain basement material at $9 per kilogram.
At conception in 2010, the duo demonstrated that copper nanowires on glass could be used to make a transparent conducting film, but they were deemed unfeasible for practical use because they would clump together. With a few revisions of the process, Wiley and Rathmell have solved the clumping problem and are ready to show the world that copper nanowires are a logical replacement for the ITO film used in screens — also holding promise for foldable electronics and improved solar cells of the future.
Rathmell and Wiley’s findings are published in Advanced Materials: The Synthesis and Coating of Long, Thin Copper Nanowires to Make Flexible, Transparent Conducting Films on Plastic Substrates.