Novel transistor design improves precision in wearable electronic skin technology

The recent advancement of miniaturized and portable electronics, particularly wearable and flexible devices, has increased the demand for self-powered sensing technologies. Among these, triboelectric nanogenerators (TENGs) have received increased attention for developing highly sensitive tactile sensors. TENGs convert external mechanical stimuli into electrical signals through redistribution of electric charges. They are particularly attractive for the development of advanced electronic skin and intelligent robotics. However, conventional tribotronic devices suffer from non-tuneable sensitivity and pose challenges in integration into large-area architectures, limiting practical applications.

To address these limitations, a research team led by Associate Professor Jaekyun Kim from the Department of Photonics and Nanoelectronics at Hanyang University in South Korea has developed a novel vertically integrated dual-gated tribotronic transistor. "Our vertical dual-gate architecture not only offers gate-tunable amplification of the triboelectronic responses, but also minimizes pixel footprint, enabling high-density, large-area integration," explains Dr. Kim. Their study was made available online on April 9, 2026, and published in Volume 153 of Nano Energy on June 15, 2026.

The proposed dual-gated tribotronic transistor features a polydimethylsiloxane (PDMS) triboelectric sensing layer as the top gate, stacked on top of a dedicated gate insulator, which in turn is positioned above an indium-tin-zinc-oxide (ITZO) thin-film transistor (TFT). This innovative configuration provides synergistic control of sensitivity.

In its default state, the bottom gate sets the baseline current flowing through the ITZO transistor. To enable contact and proximity sensing, the device first undergoes a charging phase, in which a stainless-steel plate comes into contact with the PDMS surface. This causes triboelectric charges to form at the interface. As the plate separates from the PDMS layer, these accumulated charges create a triboelectric potential that acts as the top-gate voltage, which suppresses the current flow through the ITZO transistor.

As the charged plate or another object approaches the PDMS surface again, the triboelectric potential gradually decreases, causing the transistor current to recover, based on the proximity of the plate or surface. This change in current serves as the tribotronic response, indicating contact or proximity. Meanwhile, the bottom-gate voltage sets the baseline current, allowing the sensitivity to be electrically tuned. Specifically, the researchers found that the sensitivity increased with increasing bottom-gate voltage.

The researchers also showed that increasing the contact pressure enlarges the effective contact area between the PDMS layer and the contacting object, generating more triboelectric charge and producing a stronger response.

Additionally, the device exhibited stable response and recovery times of 127 and 212 milliseconds, respectively, during each contact-separation cycle. It also maintained stable performance without noticeable degradation after 1,000 operating cycles.

To demonstrate active tactile sensing, the researchers fabricated a 10 × 10 transistor array using the proposed architecture. After initially charging the sensing layer with a stainless-steel plate, they demonstrated pixel-level responses to finger touches as well as reliable proximity sensing at distances of up to 500 micrometers using a stainless-steel probe.

"Our research could contribute to the development of electronic skin systems that allow robots, prosthetic devices, and wearable electronics to perceive touch, pressure, and proximity more precisely," remarks Dr. Kim. "This will lead to safer and more reliable human–machine interaction, with applications in healthcare robots, health monitoring and autonomous systems."

Overall, this innovative architecture provides a scalable platform for programmable, mechanically robust tribotronic sensor arrays, paving the way for advanced human–machine interfaces.