Discarded electronic devices, such as cell phones, are a rapidly increasing source of waste. One solution to the problem is employing components derived from renewable resources that are easily disposed of. Scientists have now built a prototype circuit board composed of sheet paper with completely integrated electrical components that can be burned or left to degrade.
An electronic circuit printed on paper could be a more flexible and disposable option for single-use electronics. Image Credit: Adapted from ACS Applied Materials & Interfaces, 2022.
The study was published in the ACS Applied Materials & Interfaces journal.
Most small electronic gadgets use circuit boards comprised of glass fibers, resins, and metal wiring. Because these boards are difficult to recycle and bulky, they are unsuitable for use in point-of-care medical devices, environmental monitoring, or personal wearable gadgets.
Paper-based circuit boards, for example, should be simpler to dispose of, less costly, and more adaptable. On the other hand, current possibilities require specialist paper or just regular metal circuitry components put onto a sheet of paper. Choi and co-workers instead aimed to create circuitry that was easy to build and had all of the electronic components entirely integrated into the sheet.
The group created an amplifier-style circuit using resistors, capacitors, and a transistor printed on paper. They began by printing channels in a straightforward pattern using wax onto paper.
The researchers printed semi-conductive and conductive inks, which soaked into the sections not blocked by wax, after melting the wax so that it soaked into the paper. The scientists screen-printed more conductive metal parts and cast an electrolyte made of gel onto the sheet.
The resistor, capacitor, and transistor designs all functioned satisfactorily in tests. Even when the components were added, the finished circuit was exceedingly flexible and thin, similar to paper.
To illustrate the circuit’s degradability, the researchers set fire to the entire device, swiftly burning to ash. According to the experts, this is a step toward making fully disposable electrical gadgets.
The National Science Foundation provided funding for the researchers.
Journal Reference
Landers, M., et al. (2022) Integrated Papertronic Techniques: Highly Customizable Resistor, Supercapacitor, and Transistor Circuitry on a Single Sheet of Paper. ACS Applied Materials & Interfaces. doi.org/10.1021/acsami.2c13503.