Seoul National University researchers have developed an ultra-low-voltage electrochemical organic light-emitting transistor that can simultaneously perform signal processing, memory, and light emission within a single semiconductor device. By introducing an ion transport enhancer into the light-emitting polymer semiconductor channel, the team enabled electric-double-layer formation at the drain electrode interface, allowing efficient electron injection without relying on the high voltages or unstable n-type doping used in conventional approaches. As a result, the device maintained a simple single-active-layer structure while achieving both low-voltage operation and wide, spatially-pinned light emission together with neuromorphic signal processing functionality.
Wearable electronics are rapidly evolving beyond smartwatches and smart glasses into next-generation user-friendly platforms, with future expansion toward on-skin and implantable devices. In particular, on-skin wearable devices, together with integrated semiconductor technologies that combine sensing, signal processing, memory, and display functions in a single platform, are regarded as key enabling technologies for next-generation healthcare and the future electronics industry.
More recently, wearable electronics have advanced beyond simple bio-signal detection toward real-time signal processing and visualization. However, until now, these functions have typically been implemented using separate devices connected together, resulting in complex structures, bulky and rigid components, and high energy consumption. Therefore, integrating multiple functions within a simple device architecture has become a major challenge.
Organic light-emitting transistors have attracted attention as promising candidates for next-generation wearable electronics because they can combine transistor and light-emitting diode functions in a single device. However, conventional organic transistors with a lateral electrode structure require high operating voltages of 80 to 180 V because of the long distance between electrodes and the large electron-injection barrier. Even when electrochemical ion doping is used to lower the operating voltage, more than 3.5 V is still required, and the emission zone remains narrow and unstable, limiting their practical use in real displays and intelligent wearable electronic systems.
The research team developed an ultra-low-voltage electrochemical organic light-emitting transistor that integrates signal processing, memory, and light emission within a single organic transistor. By incorporating an ion transport enhancer into the active layer to induce electric-double-layer formation at the electrode interface, the team introduced a new mechanism for efficient electron injection without relying on the high voltages or unstable doping used in conventional approaches. This enabled light emission even at voltages < 3.5 V previously considered too low for operation, while maintaining a wide and stable emission zone.
The device also exhibited signal-processing and memory characteristics, with responses accumulating under repeated stimuli and retained over time, and was further demonstrated in a flexible wearable display system powered by only two 1.5 V batteries. This study shows that stable light emission and intelligent functionality can be achieved simultaneously even in a simple single-active-layer architecture, greatly expanding the potential of organic transistors for wearable applications.
This study is significant in that it integrates signal processing, memory, and light emission into a single device, reducing the limitations of conventional wearable electronic systems that require multiple separate components to be fabricated and interconnected. In particular, by also demonstrating cumulative and retentive responses to input stimuli, it highlights the potential of next-generation electronics that can process information and immediately display the result through light.
Whereas conventional wearable devices make it difficult for users to check measured signals in real time while moving, this technology points toward real-time monitoring and immediate information delivery. It is expected to be extended to applications such as rehabilitation, emergency patient care, exercise monitoring, on-skin electronics, and smart healthcare, and may serve as a key enabling technology for related industries.
Professor Tae-Woo Lee has demonstrated world-leading research competitiveness through consecutive publications in Science and Nature in 2026. This work goes beyond conventional light-emitting devices by integrating light-emission, signal processing, and memory functionalities into a single semiconductor device at low voltage, presenting a new direction for next-generation intelligent wearable electronics.
Professor Tae-Woo Lee, who led the study, said, "This work is particularly meaningful in that it demonstrates that all functions can be integrated within a single semiconductor device, without the need to separately fabricate and connect processing, memory, and display units." He added, "Going forward, we plan to further develop this technology into an on-skin semiconductor platform applicable to intelligent artificial skin and wearable healthcare."
This technology is also significant in that it goes beyond conventional light-emitting semiconductors by demonstrating multifunctionality into a single low-voltage semiconductor device. In this sense, it presents a new direction for intelligent on-skin wearable electronics that enable real-time interaction between humans and machines.
□ Introduction to the SNU College of Engineering
Seoul National University (SNU) founded in 1946 is the first national university in South Korea. The College of Engineering at SNU has worked tirelessly to achieve its goal of 'fostering leaders for global industry and society.' In 12 departments, 323 internationally recognized full-time professors lead the development of cutting-edge technology in South Korea and serving as a driving force for international development.
