With a cocktail of carbon-based inks, engineers have made the first fully printable and recyclable electronic circuits on paper. The sturdy, high-performance devices last for months, and can be decomposed at the end to recover the carbon materials so they can be reused for printing.
The recyclable carbon electronics are not meant to supplant silicon, says Aaron Franklin, an electrical and computer engineering professor at Duke University who reported the advance in Nature Electronics. Instead, this is a way to satisfy the thirst for ubiquitous, embedded electronics without sending enormous amounts of often toxic waste to landfills and the environment.
“It is absolutely not targeted at upending the half-trillion dollar semiconductor industry,” he says. “People want more and more data, and more sensors to capture that data. Be it agricultural or medical or environmental sensors, there’s an increasing appetite for getting electronics all over the place.”
Research on printed and transient electronics has exploded in recent years to meet this demand for low-cost, eco-friendly sensors. Transient electronics are designed to degrade and disappear after use instead of lingering in the body or the environment. But they still create silicon and other waste. Meanwhile, past efforts to print circuits still utilize some techniques outside of the printer, Franklin says. “We emphasize print-in-place. We put the substrate on printer, print everything and then pull it out, and the device is ready to test. And the performance is on par if not better than most other printed transistors.”