Traditional electronics fabrication methods may be perfectly well-suited for making the devices that sit on our desks or slide into our pockets, but everything changes when those devices need to be worn on the body. Wearable devices must be able to stretch and bend with the body, and they have to do this without rapidly wearing out and becoming unreliable or failing completely. And that leads to the problem, which is that conventional electronics are filled with rigid circuit boards, chips, and other components that are not only uncomfortable against the skin, but that are also completely inflexible.
Many new technologies have been developed in recent years in an attempt to address this issue, but none have fully met our present needs. While flexible wearable electronics have been developed, they tend to have issues with durability or performance. That may change in the near future, however, thanks to the work of a group headed up by researchers at Sungkyunkwan University in South Korea. They have described a novel method to fabricate self-healing and stretchable electronic components that can withstand the difficult conditions experienced by wearable devices.
Specifically, the team has developed a scalable and reconfigurable method for assembling soft, damage-resistant transistors. These components, which can be integrated into fully functional circuits, are designed to maintain their electrical performance even after being stretched, bent, or damaged.
Bending with the body causes no damage (📷: J. Jang et al.)
Unlike typical stretchable electronics, which may still rely on some rigid or semi-flexible parts, the new transistors developed by the researchers use soft, elastic materials throughout. These include a self-healing polymer as the gate dielectric, an organic semiconductor blend for the active layer, and a carbon-nanotube-based composite for the electrodes. Even after being physically damaged, these layers are able to reconnect at the molecular level, restoring both mechanical and electrical functionality.
An important aspect of this work is that it appears to be practical for real-world applications. The team demonstrated that their transistors can be mass-produced using a process called transfer printing. This technique allows each functional layer to be fabricated separately and then assembled into a complete device — much like stacking sheets of paper. That would greatly simplify using this process to produce a commercial device.
To show off the potential of their system, the researchers created 5 by 5 transistor arrays integrated with pressure sensors and soft display pixels. These devices could not only record tactile data and provide feedback, but also remain operational after being implanted in living tissue.
This technology has the potential to transform how we think about wearable and implantable devices. Systems built using the approach could be adapted for a wide range of uses, from long-term health monitoring to next-generation prosthetics and neuroprosthetic implants. And because they can be reassembled like LEGO blocks, the components are easily upgradable or replaceable, making them highly versatile.
The researchers plan to refine their designs further by enhancing electrical performance and optimizing the materials used. Ultimately, they hope to develop high-speed, high-density circuits that can function reliably in the challenging conditions found on the human body.