%65%6c%65%63%74%72%6f%6e
-
A Breakthrough Concept in Nano-Printing Technology
<(From Left) Professor Inkyu Park, Ph.D candidate Byung-Ho Kang, Researcher Jun-Ho Jeong, Professor Junseong Ahn>
A breakthrough technology has been developed that allows metal circuits floating on water to be transferred directly onto any desired surface. A South Korean research team has introduced a novel technique capable of transferring ultra-fine nano-circuits onto plant leaves and fruits, as well as curved automotive surfaces and robot exteriors, all without causing any damage. This technology is expected to be widely utilized across various cutting-edge industries, including smart agriculture, wearable healthcare, and bioelectronics.
KAIST announced on June 15th that a joint research team led by Distinguished Professor Inkyu Park from the Department of Mechanical Engineering, Dr. Jun-Ho Jeong from the Korea Institute of Machinery and Materials and Professor Junseong Ahn from Korea University has successfully developed "Water-Floating Nano-Transfer Printing (WF-nTP)." This technology enables precision metal thin films floated on water to be transferred onto various 3D surfaces.
Conventional nano-transfer printing (nTP), which is widely used to manufacture electronic devices and sensors, typically requires high heat, intense pressure, adhesives, or toxic chemical solvents. Consequently, applying this method to biological tissues or complex curved surfaces that are sensitive to heat and pressure has proven highly challenging.
To overcome these limitations, the research team proposed a completely new approach: floating metal circuits on the surface of water.
Fabrication: The team deposited an ultra-thin layer of metals such as gold (Au), platinum (Pt), palladium (Pd), or nickel (Ni) onto a polymer mold.
Separation: They then used plasma gas which has a high-energy state of ionized gas to selectively remove (etch) a part of the mold.
Floating: When this structure is placed in water, water infiltrates through the microscopic gaps, causing the 20-nanometer (nm) thick metal film to float to the surface on its own while perfectly maintaining its original shape.
<Overview of the water-floated nano mesh and versatile transfer technique>
The research team transferred the metal circuits using a "scooping" method, which involves submerging the target object beneath the floating film and slowly lifting it upward. As the water evaporates, capillary force (the force that moves liquid through narrow spaces) tightly adheres the circuit to the surface. Once the water completely dries, intermolecular forces come into play, securing the circuit firmly in place without the need for any adhesive.
Notably, the team also succeeded in transferring circuits onto hydrophobic (water-repellent) surfaces, such as lotus leaves. By adding a small amount of ethanol to the water to lower its surface tension (the property of a liquid surface that causes it to shrink), they effectively overcame a major limitation of conventional technologies.
This technology holds immense potential for widespread application because it can adapt to diverse surfaces while flawlessly preserving the nano-patterns. Using this method, the research team fabricated Surface-Enhanced Raman Scattering (SERS) sensors which are used for high-sensitivity detection of trace chemical substances and attached them directly to plant leaves and fruit surfaces. Through this, they successfully detected thiram, a pesticide component, on the surfaces of leaves and fruits. Furthermore, they successfully implemented a wearable, high-performance hydrogen gas sensor by transferring a palladium (Pd) mesh onto highly flexible thermoplastic polyurethane (TPU) fibers.
<Research Image(AI-generated)>
Distinguished Professor Inkyu Park stated: "This technology is highly significant as it shatters the substrate limitations of conventional nano-transfer printing, allowing nano-patterns to be transferred onto sensitive surfaces like living plant leaves or human skin without heat or adhesives. We expect it to evolve into a core platform technology for wearable sensors and bioelectronics, finding applications in smart agriculture for pesticide detection without damaging crops, wearable health monitoring devices, bioelectronic devices, and electronic skins for next-generation robots."
This research, with PhD student Byung-Ho Kang from the KAIST Department of Mechanical Engineering participating as the first author, was published online on March 30, 2026, in the prestigious international academic journal Nature Communications.
The study authors include Byung-Ho Kang, Ji-Hwan Ha, Yeongjae Kwon, Sohee Jeon, Donho Lee, Byeongmin Kang, Soon Hyoung Hwang, Junseong Ahn, Jun-Ho Jeong, and Inkyu Park.
Meanwhile, this research was conducted with funding from the Ministry of Science and ICT through the National Research Foundation of Korea (NRF) Mid-Career Researcher Support Program, and the Ministry of Trade, Industry and Energy through the Korea Evaluation Institute of Industrial Technology (KEIT) Alchemist Project.
2026.06.15 View 2129 -
KAIST Reveals the Orbital Principle of Electron Motion for Realizing Memory of Dreams
<(From Left) Dr. Geun-Hee Lee, Professor Kyung-Jin Lee, Professor Kyoung-Whan Kim>
Research is actively underway to develop a “dream memory” that can reduce heat generation in smartphones and laptops while delivering faster performance and lower power consumption. Korean researchers have now proposed a new possibility for controlling magnetism using the exchange interaction of electron orbitals—the motion of electrons orbiting around an atomic nucleus—rather than relying on the conventional exchange interaction of electron spin, the rotational property of electrons inside semiconductors.
KAIST (President Kwang Hyung Lee) announced on the 16th of March that a joint research team led by Professor Kyung-Jin Lee of the Department of Physics at KAIST and Professor Kyoung-Whan Kim of the Department of Physics at Yonsei University (President Dong-Sup Yoon) has established, for the first time in the world, a new theoretical framework enabling magnetism to be freely controlled through orbital exchange interaction*, surpassing the limitations of conventional technologies that control magnetism using electric currents.*Orbital exchange interaction: a phenomenon in which the orbitals formed by electrons moving around an atomic nucleus interact with one another, thereby influencing the direction or properties of magnetism.
Until now, next-generation memory research has mainly focused on the spin of electrons. Spin refers to the property of electrons that rotate on their own axis like tiny spinning tops, and information can be stored by using the direction of this rotation. However, electrons simultaneously move around the atomic nucleus along paths known as orbitals. In this study, the research team theoretically demonstrated that when electric current flows, the orbital energy of electrons interacts directly with the orbitals of magnetic materials, enabling the transmission of information. Through this mechanism, they confirmed that the properties of magnets can be altered much more efficiently than with conventional spin-based approaches.
The most significant outcome of this research is the discovery that electric current does not merely change the direction of a magnet but can also modify the intrinsic properties of the magnet itself, such as the magnetic anisotropy (a magnet’s preferred direction) and rotational characteristics.
In particular, calculations by the research team showed that orbital-based control effects could be significantly stronger than existing spin-based methods. This finding suggests the possibility of a future era of orbital-based electronic devices, in which orbitals rather than spin play the central role in semiconductor components. The researchers also proposed practical experimental methods to measure these effects, which is expected to increase the potential for industrial applications.
The principle may also apply to altermagnetic materials, which have recently attracted significant attention in academia. Altermagnetism refers to a new form of magnetic material in which electron spins within atoms are arranged in alternating directions in an ordered pattern. Although these materials do not appear magnetic externally, they strongly influence electron motion. Because of this property, they allow precise control of electron states and are considered promising for high-speed, low-power semiconductor devices and next-generation memory technologies. The study therefore provides a strong theoretical foundation for developing future logic and memory devices.
Dr. Geun-Hee Lee stated, “This study demonstrates that controlling magnetism with electric current does not necessarily have to rely solely on spin. A new perspective—understanding and controlling magnetism using the orbital motion of electrons—will become an important milestone for the development of next-generation ultra-fast, low-power memory.”
In this research, Dr. Geun-Hee Lee (KAIST) participated as the first author, while Professor Kyoung-Whan Kim (Yonsei University) and Professor Kyung-Jin Lee (KAIST) served as co-corresponding authors. The results were published on February 2 in the internationally renowned journal Nature Communications, recognizing the academic significance of the work.
※ Paper title: “Orbital exchange-mediated current control of magnetism,” DOI: https://doi.org/10.1038/s41467-026-68846-x
This research was supported by the Frontier Challenge R&D Project, the Mid-Career Researcher Program, the Science Research Center (SRC) program, the Early Career Researcher Program of the National Research Foundation of Korea, and Samsung Electronics.
2026.03.16 View 1962 -
KAIST to Showcase K-Tech Competitiveness at KAIST Pavilion during CES 2026
< Figure 1. Bird's-eye view of the KAIST Pavilion at CES 2026 >
KAIST announced on January 2nd that it will participate in the Consumer Electronics Show (CES 2026), held from January 6 to 9, 2026, at Eureka Park in the Venetian Expo, Las Vegas. KAIST will operate a dedicated 111㎡ "KAIST Pavilion" to showcase its innovative technologies to global corporations and investors.
A total of 12 startups will participate in the KAIST Pavilion at CES 2026. Notably, eight of these companies are built on core AI technologies, highlighting KAIST's artificial intelligence research capabilities and its achievements in technology commercialization.
The participating companies will unveil solutions targeting the global market across various high-tech sectors centered on AI, including robotics, bio-health, hardware devices, and content technology.
One of the standout participants is Hypergram, a faculty-led startup. Hypergram will introduce 'HG VNIR Pro,' the world’s first commercialized compressive hyperspectral imaging technology. This product is an end-to-end solution that integrates industrial-grade precision hardware with AI analysis software, capable of detecting minute chemical properties invisible to the human eye in real-time. During the exhibition, the company plans to demonstrate high-precision AI image analysis using its high-speed hyperspectral machine vision camera.
< Figure 2. Hypergram >
MOSS, a winner of the CES 2026 Innovation Award, will exhibit an AI-based, all-in-one mobile music production platform. This platform allows the general public and indie musicians to create high-quality music without a heavy financial burden. Visitors can experience the intuitiveness and innovation of the technology at an AI experience zone, where they can create music by linking the MOSS app with the dedicated hardware, 'MOSS Pocket Studio.'
< Figure 3. MOSS (Innovation Award Winning Product) >
BareulEye is developing a medical AI diagnostic solution that detects high-resolution changes in internal organ microstructures based on AI-powered quantitative ultrasound analysis technology. At CES 2026, they will unveil a 3D volume reconstruction technology that utilizes smart mirror-based self-ultrasound imaging.
Leveraging this technological prowess, BareulEye recently secured approximately $10 million (14 billion KRW) in a strategic Series A investment from a leading global healthcare company. Led by Professor Hyeon-min Bae, the Director of the KAIST Institute for Startup & Entrepreneurship and CEO of BareulEye, the company plans to accelerate joint technology development and overseas market expansion.
< Figure 4. BareulEye >
In addition to these, various KAIST startups leading innovation in AI, bio, and hardware devices will participate to solidify their foundations for entering the global market.
The KAIST Pavilion is designed with an open layout and large-scale LED displays to attract attention, featuring independent spaces for each company to facilitate in-depth technical presentations and investment consultations.
"Through CES 2026, we aim to imprint the AI-driven innovative technologies of KAIST startups on the global stage and establish a practical bridgehead for their international expansion," said Keon Jae Lee, Vice President of the KAIST Institute for Technology Value Creation.
2026.01.02 View 4770 -
Professor Jae-woong Jeong Wins September's Scientist and Engineer of the Month Award
<Professor Jae-Woong Jeong from Department of Electrical and Electronic Engineering>
The Ministry of Science and ICT and the National Research Foundation of Korea have announced that Professor Jae-Woong Jeong from KAIST Department of Electrical and Electronic Engineering has been selected as the September recipient of the "Scientist of the Month" award.
The "Scientist of the Month" award recognizes researchers who have made a significant contribution to the development of science and technology by creating unique R&D achievements over the past three years. The award is given to one person each month and includes a commendation from the Minister of Science and ICT and a 10 million KRW prize, funded by the Science and Technology Promotion Fund/Lottery Fund of the Ministry of Science and ICT. In the lead-up to "World Patient Safety Day (September 17)," the Ministry of Science and ICT and the National Research Foundation selected Professor Jeong Jae-Woong as the award recipient for his contribution to healthcare innovation through convergence research on wearable and implantable electronic devices and medical instruments, including the development of an intravenous (IV) needle that softens in response to body temperature to enhance patient safety.
Intravenous injection is a treatment method that involves directly injecting medication into a blood vessel. It is widely used in the medical field due to its ability to provide rapid and continuous drug effects. However, conventional IV needles, made of rigid metal or plastic, can damage blood vessel walls or cause complications like phlebitis. Furthermore, there is a risk of needle-stick injuries and subsequent disease transmission for medical professionals during the disposal process.
Professor Jae-Woong Jeong developed a variable-stiffness* needle that is rigid at room temperature but softens like biological tissue when inserted into the body. This innovation utilizes the unique property of the liquid metal gallium, which changes from a solid to a liquid phase in response to body temperature. * Variable-stiffness: The characteristic of being able to adjust the level of rigidity (stiffness) according to a situation or condition.
The variable-stiffness needle not only ensures a patient's free movement but also maintains a soft state at room temperature after use, preventing needle-stick accidents for medical professionals and fundamentally eliminating the issue of unethical needle reuse.
< An intravenous needle that softens with body temperature. Intravenous injection is a treatment method that involves directly injecting medication into a blood vessel, which allows for a rapid and continuous supply of drugs, making it a globally accepted form of patient care. This research utilized the property of liquid metal gallium, which changes from a solid to a liquid state in response to body temperature, to develop a variable-stiffness intravenous needle that is rigid but softens like tissue upon insertion into the body. This needle allows for stable drug delivery without damaging blood vessels, even when the patient moves. Furthermore, the irreversible softening due to the supercooling phenomenon of gallium can fundamentally prevent post-use needle-stick injuries or unethical reuse, contributing to the safety of both patients and medical staff. This variable-stiffness technology is expected to be widely utilized in the implementation of various wearable and implantable devices that can change their properties according to different situations and purposes. >
Furthermore, Professor Jae-woong Jung focused on the phenomenon in which the temperature of surrounding tissue decreases when a drug leaks during intravenous (IV) injection. He developed a function that enables real-time monitoring of local body temperature by integrating a nanofilm temperature sensor into an IV needle, thereby allowing real-time detection of IV drug leakage.
This research achievement, which presents a new vision for promoting patient health and ensuring medical staff safety as required by the World Health Organization (WHO), was published as the cover article of the international journal Nature Biomedical Engineering in August 2024.
Professor Jae-Woong Jeong stated, “This research is highly significant as it proposes a way to overcome the problems caused by conventional rigid medical needles and solves the infection risks from needle-stick injuries or reuse.” He added, “I will continue to dedicate my efforts to R&D so that variable-stiffness needle technology can evolve into a core technology in the medical field, enhancing the safety of both patients and medical professionals.
To provide more robust support to researchers who lead such outstanding achievements, the Ministry of Science and ICT has prepared a record-high R&D budget of 11.8 trillion KRW (government proposal), including the Life Sciences (Bio) Medical Technology Development Project (361.1 billion KRW in '25 → 434.3 billion KRW in '26, proposed). The Ministry plans to strengthen investment in future industries, such as advanced life sciences, and will further reinforce rewards and recognition for researchers who produce excellent results to foster a researcher-centric R&D ecosystem.
2025.09.05 View 3556 -
Approaches to Human-Robot Interaction Using Biosignals
<(From left) Dr. Hwa-young Jeong, Professor Kyung-seo Park, Dr. Yoon-tae Jeong, Dr. Ji-hoon Seo, Professor Min-kyu Je, Professor Jung Kim >
A joint research team led by Professor Jung Kim of KAIST Department of Mechanical Engineering and Professor Min-kyu Je of the Department of Electrical and Electronic Engineering recently published a review paper on the latest trends and advancements in intuitive Human-Robot Interaction (HRI) using bio-potential and bio-impedance in the internationally renowned academic journal 'Nature Reviews Electrical Engineering'.
This review paper is the result of a collaborative effort by Dr. Kyung-seo Park (DGIST, co-first author), Dr. Hwa-young Jeong (EPFL, co-first author), Dr. Yoon-tae Jeong (IMEC), and Dr. Ji-hoon Seo (UCSD), all doctoral graduates from the two laboratories. Nature Reviews Electrical Engineering is a review specialized journal in the field of electrical, electronic, and artificial intelligence technology, newly launched by Nature Publishing Group last year. It is known to invite world-renowned scholars in the field through strict selection criteria. Professor Jung Kim's research team's paper, titled "Using bio-potential and bio-impedance for intuitive human-robot interaction," was published on July 18, 2025. (DOI: https://doi.org/10.1038/s44287-025-00191-5)
This review paper explains how biosignals can be used to quickly and accurately detect movement intentions and introduces advancements in movement prediction technology based on neural signals and muscle activity. It also focuses on the crucial role of integrated circuits (ICs) in maximizing low-noise performance and energy efficiency in biosignal sensing, covering thelatest development trends in low-noise, low-power designs for accurately measuring bio-potential and impedance signals.
The review emphasizes the importance of hybrid and multi-modal sensing approaches, presenting the possibility of building robust, intuitive, and scalable HRI systems. The research team stressed that collaboration between sensor and IC design fields is essential for the practical application of biosignal-based HRI systems and stated that interdisciplinary collaboration will play a significant role in the development of next-generation HRI technology. Dr. Hwa-young Jeong, a co-first author of the paper, presented the potential of bio-potential and impedance signals to make human-robot interaction more intuitive and efficient, predicting that it will make significant contributions to the development of HRI technologies such as rehabilitation robots and robotic prostheses using biosignals in the future. This research was supported by several research projects, including the Human Plus Project of the National Research Foundation of Korea.
2025.07.24 View 6781 -
Professor Jung-woo' Choi ‘s Team Comes in First at the World's Top Acoustic AI Challenge
<Photo1. (From left) Ph.D candidate Yong-hoo Kwon, M.S candidate Do-hwan Kim, Professor Jung-woo Choi, Dr. Dong-heon Lee>
'Acoustic separation and classification technology' is a next-generation artificial intelligence (AI) core technology that enables the early detection of abnormal sounds in areas such as drones, fault detection of factory pipelines, and border surveillance systems, or allows for the separation and editing of spatial audio by sound source when producing AR/VR content.
On the 11th of July, a research team led by Professor Jung-woo Choi of KAIST's Department of Electrical and Electronic Engineering won first place in the 'Spatial Semantic Segmentation of Sound Scenes' task of the 'DCASE2025 Challenge,' the world's most prestigious acoustic detection and analysis competition.
This year’s challenge featured 86 teams competing across six tasks. In this competition, the KAIST research team achieved the best performance in their first-ever participation to Task 4. Professor Jung-woo Choi’s research team consisted of Dr. Dong-heon, Lee, Ph.D. candidate Young-hoo Kwon, and M.S. candidate Do-hwan Kim.
Task 4 titled 'Spatial Semantic Segmentation of Sound Scenes' is a highly demanding task requiring the analysis of spatial information in multi-channel audio signals with overlapping sound sources. The goal was to separate individual sounds and classify them into 18 predefined categories. The research team plans to present their technology at the DCASE workshop in Barcelona this October.
<Figure 1. Example of an acoustic scene with multiple mixed sounds>
Early this year, Dr. Dong-heon Lee developed a state-of-the-art sound source separation AI that combines Transformer and Mamba architectures. During the competition, centered around researcher Young-hoo Kwon, they completed a ‘chain-of-inference architecture' AI model that performs sound source separation and classification again, using the waveforms and types of the initially separated sound sources as clues. This AI model is inspired by human’s auditory scene analysis mechanism that isolates individual sounds by focusing on incomplete clues such as sound type, rhythm, or direction, when listening to complex sounds.
Through this, the team was the only participant to achieve double-digit performance (11 dB) in 'Class-Aware Signal-to-Distortion Ratio Improvement (CA-SDRi)*,' which is the measure for ranking how well the AI separated and classified sounds, proving their technical excellence.
Class-Aware Signal-to-Distortion Ratio Improvement (CA-SDRi): Measures how much clearer (less distorted) the desired sound is separated and classified compared to the original audio, in dB (decibels). A higher number indicates more accurate and cleaner sound separation.
Prof. Jung-woo Choi remarked, "The research team has showcased world-leading acoustic separation AI models for the past three years, and I am delighted that these results have been officially recognized." He added, "I am proud of every member of the research team for winning first place through focused research, despite the significant increase in difficulty and having only a few weeks for development."
<Figure 2. Time-frequency patterns of sound sources separated from a mixed source>
The IEEE DCASE Challenge 2025 was held online, with submissions accepted from April 1 to June 15 and results announced on June 30. Since its launch in 2013, the DCASE Challenge has served as a premier global platform of IEEE Signal Processing Society for showcasing cutting-edge AI models in acoustic signal processing.
This research was supported by the Mid-Career Researcher Support Project and STEAM Research Project of the National Research Foundation of Korea, funded by the Ministry of Education, Science and Technology, as well as support from the Future Defense Research Center, funded by the Defense Acquisition Program Administration and the Agency for Defense Development.
2025.07.13 View 4687 -
Military Combatants Usher in an Era of Personalized Training with New Materials
< Photo 1. (From left) Professor Steve Park of Materials Science and Engineering, Kyusoon Pak, Ph.D. Candidate (Army Major) >
Traditional military training often relies on standardized methods, which has limited the provision of optimized training tailored to individual combatants' characteristics or specific combat situations. To address this, our research team developed an e-textile platform, securing core technology that can reflect the unique traits of individual combatants and various combat scenarios. This technology has proven robust enough for battlefield use and is economical enough for widespread distribution to a large number of troops.
On June 25th, Professor Steve Park's research team at KAIST's Department of Materials Science and Engineering announced the development of a flexible, wearable electronic textile (E-textile) platform using an innovative technology that 'draws' electronic circuits directly onto fabric.
The wearable e-textile platform developed by the research team combines 3D printing technology with new materials engineering design to directly print flexible and highly durable sensors and electrodes onto textile substrates. This enables the collection of precise movement and human body data from individual combatants, which can then be used to propose customized training models.
Existing e-textile fabrication methods were often complex or limited in their ability to provide personalized customization. To overcome these challenges, the research team adopted an additive manufacturing technology called 'Direct Ink Writing (DIW)' 3D printing.
< Figure 1. Schematic diagram of e-textile manufactured with Direct Ink Writing (DIW) printing technology on various textiles, including combat uniforms >
This technology involves directly dispensing and printing special ink, which functions as sensors and electrodes, onto textile substrates in desired patterns. This allows for flexible implementation of various designs without the complex process of mask fabrication. This is expected to be an effective technology that can be easily supplied to hundreds of thousands of military personnel.
The core of this technology lies in the development of high-performance functional inks based on advanced materials engineering design. The research team combined styrene-butadiene-styrene (SBS) polymer, which provides flexibility, with multi-walled carbon nanotubes (MWCNT) for electrical conductivity. They developed a tensile/bending sensor ink that can stretch up to 102% and maintain stable performance even after 10,000 repetitive tests. This means that accurate data can be consistently obtained even during the strenuous movements of combatants.
< Figure 2. Measurement of human movement and breathing patterns using e-textile >
Furthermore, new material technology was applied to implement 'interconnect electrodes' that electrically connect the upper and lower layers of the fabric. The team developed an electrode ink combining silver (Ag) flakes with rigid polystyrene (PS) polymer, precisely controlling the impregnation level (how much the ink penetrates the fabric) to effectively connect both sides or multiple layers of the fabric. This secures the technology for producing multi-layered wearable electronic systems integrating sensors and electrodes.
< Figure 3. Experimental results of recognizing unknown objects after machine learning six objects using a smart glove >
The research team proved the platform's performance through actual human movement monitoring experiments. They printed the developed e-textile on major joint areas of clothing (shoulders, elbows, knees) and measured movements and posture changes during various exercises such as running, jumping jacks, and push-ups in real-time.
Additionally, they demonstrated the potential for applications such as monitoring breathing patterns using a smart mask and recognizing objects through machine learning and perceiving complex tactile information by printing multiple sensors and electrodes on gloves. These results show that the developed e-textile platform is effective in precisely understanding the movement dynamics of combatants.
This research is an important example demonstrating how cutting-edge new material technology can contribute to the advancement of the defense sector. Major Kyusoon Pak of the Army, who participated in this research, considered required objectives such as military applicability and economic feasibility for practical distribution from the research design stage.
< Figure 4. Experimental results showing that a multi-layered e-textile glove connected with interconnect electrodes can measure tensile/bending signals and pressure signals at a single point >
Major Pak stated, "Our military is currently facing both a crisis and an opportunity due to the decrease in military personnel resources caused by the demographic cliff and the advancement of science and technology. Also, respect for life in the battlefield is emerging as a significant issue. This research aims to secure original technology that can provide customized training according to military branch/duty and type of combat, thereby enhancing the combat power and ensuring the survivability of our soldiers."
He added, "I hope this research will be evaluated as a case that achieved both scientific contribution and military applicability."
This research, where Kyusoon Pak, Ph.D. Candidate (Army Major) from KAIST's Department of Materials Science and Engineering, participated as the first author and Professor Steve Park supervised, was published on May 27, 2025, in `npj Flexible Electronics (top 1.8% in JCR field)', an international academic journal in the electrical, electronic, and materials engineering fields.
* Paper Title: Fabrication of Multifunctional Wearable Interconnect E-textile Platform Using Direct Ink Writing (DIW) 3D Printing
* DOI: https://doi.org/10.1038/s41528-025-00414-7
This research was supported by the Ministry of Trade, Industry and Energy and the National Research Foundation of Korea.
2025.06.25 View 9275 -
KAIST Successfully Develops High-Performance Water Electrolysis Without Platinum, Bringing Hydrogen Economy Closer
< Photo 1. (Front row, from left) Jeesoo Park (Ph.D. Candidate), Professor Hee-Tak Kim (Back row, from left) Kyunghwa Seok (Ph.D. Candidate), Dr. Gisu Doo, Euntaek Oh (Ph.D. Candidate) >
Hydrogen is gaining attention as a clean energy source that emits no carbon. Among various methods, water electrolysis, which splits water into hydrogen and oxygen using electricity, is recognized as an eco-friendly hydrogen production method. Specifically, proton exchange membrane water electrolysis (PEMWE) is considered a next-generation hydrogen production technology due to its ability to produce high-purity hydrogen at high pressure. However, existing PEMWE technology has faced limitations in commercialization due to its heavy reliance on expensive precious metal catalysts and coating materials. Korean researchers have now proposed a new solution to address these technical and economic bottlenecks.
KAIST (President Kwang Hyung Lee) announced on June 11th that a research team led by Professor Hee-Tak Kim of the Department of Chemical and Biomolecular Engineering, in a joint study with Dr. Gisu Doo of the Korea Institute of Energy Research (KIER, President Chang-keun Lee), has developed a next-generation water electrolysis technology that achieves high performance without the need for expensive platinum (Pt) coating.
The research team focused on the primary reason why 'iridium oxide (IrOx),' a highly active catalyst for water electrolysis electrodes, fails to perform optimally. They found that this is due to inefficient electron transfer and, for the first time in the world, demonstrated that performance can be maximized simply by controlling the catalyst particle size.
In this study, it was revealed that the reason iridium oxide catalysts do not exhibit excellent performance without platinum coating is due to 'electron transport resistance' that occurs at the interface between the catalyst, the ion conductor (hereinafter referred to as ionomer), and the Ti (titanium) substrate—core components inherently used together in water electrolysis electrodes.
Specifically, they identified that the 'pinch-off' phenomenon, where the electron pathway is blocked between the catalyst, ionomer, and titanium substrate, is the critical cause of reduced conductivity. The ionomer has properties close to an electron insulator, thereby hindering electron flow when it surrounds catalyst particles. Furthermore, when the ionomer comes into contact with the titanium substrate, an electron barrier forms on the surface oxide layer of the titanium substrate, significantly increasing resistance.
< Figure 1. Infographic related to electron transport resistance at the catalyst layer/diffusion layer interface >
To address this, the research team fabricated and compared catalysts of various particle sizes. Through single-cell evaluation and multiphysics simulations, they demonstrated, for the first time globally, that when iridium oxide catalyst particles with a size of 20 nanometers (nm) or larger are used, the ionomer mixed region decreases, ensuring an electron pathway and restoring conductivity.
Moreover, they successfully optimized the interfacial structure through precise design, simultaneously ensuring both reactivity and electron transport. This achievement demonstrated that the previously unavoidable trade-off between catalyst activity and conductivity can be overcome through meticulous interfacial design.
This breakthrough is expected to be a significant milestone not only for the development of high-performance catalyst materials but also for the future commercialization of proton exchange membrane water electrolysis systems that can achieve high efficiency while drastically reducing the amount of precious metals used.
Professor Hee-Tak Kim stated, "This research presents a new interface design strategy that can resolve the interfacial conductivity problem, which was a bottleneck in high-performance water electrolysis technology." He added, "By securing high performance even without expensive materials like platinum, it will be a stepping stone closer to realizing a hydrogen economy."
This research, with Jeesoo Park, a Ph.D. student from the Department of Chemical and Biomolecular Engineering at KAIST, as the first author, was published on June 7th in 'Energy & Environmental Science' (IF: 32.4, 2025), a leading international journal in the energy and environmental fields, and was recognized for its innovativeness and impact. (Paper title: On the interface electron transport problem of highly active IrOx catalysts, DOI: 10.1039/D4EE05816J).
This research was supported by the New and Renewable Energy Core Technology Development Project of the Ministry of Trade, Industry and Energy.
2025.06.11 View 11222 -
KAIST Research Team Develops Electronic Ink for Room-Temperature Printing of High-Resolution, Variable-Stiffness Electronics
A team of researchers from KAIST and Seoul National University has developed a groundbreaking electronic ink that enables room-temperature printing of variable-stiffness circuits capable of switching between rigid and soft modes. This advancement marks a significant leap toward next-generation wearable, implantable, and robotic devices.
< Photo 1. (From left) Professor Jae-Woong Jeong and PhD candidate Simok Lee of the School of Electrical Engineering, (in separate bubbles, from left) Professor Gun-Hee Lee of Pusan National University, Professor Seongjun Park of Seoul National University, Professor Steve Park of the Department of Materials Science and Engineering>
Variable-stiffness electronics are at the forefront of adaptive technology, offering the ability for a single device to transition between rigid and soft modes depending on its use case. Gallium, a metal known for its high rigidity contrast between solid and liquid states, is a promising candidate for such applications. However, its use has been hindered by challenges including high surface tension, low viscosity, and undesirable phase transitions during manufacturing.
On June 4th, a research team led by Professor Jae-Woong Jeong from the School of Electrical Engineering at KAIST, Professor Seongjun Park from the Digital Healthcare Major at Seoul National University, and Professor Steve Park from the Department of Materials Science and Engineering at KAIST introduced a novel liquid metal electronic ink. This ink allows for micro-scale circuit printing – thinner than a human hair – at room temperature, with the ability to reversibly switch between rigid and soft modes depending on temperature.
The new ink combines printable viscosity with excellent electrical conductivity, enabling the creation of complex, high-resolution multilayer circuits comparable to commercial printed circuit boards (PCBs). These circuits can dynamically change stiffness in response to temperature, presenting new opportunities for multifunctional electronics, medical technologies, and robotics.
Conventional electronics typically have fixed form factors – either rigid for durability or soft for wearability. Rigid devices like smartphones and laptops offer robust performance but are uncomfortable when worn, while soft electronics are more comfortable but lack precise handling. As demand grows for devices that can adapt their stiffness to context, variable-stiffness electronics are becoming increasingly important.
< Figure 1. Fabrication process of stable, high-viscosity electronic ink by dispersing micro-sized gallium particles in a polymer matrix (left). High-resolution large-area circuit printing process through pH-controlled chemical sintering (right). >
To address this challenge, the researchers focused on gallium, which melts just below body temperature. Solid gallium is quite stiff, while its liquid form is fluid and soft. Despite its potential, gallium’s use in electronic printing has been limited by its high surface tension and instability when melted.
To overcome these issues, the team developed a pH-controlled liquid metal ink printing process. By dispersing micro-sized gallium particles into a hydrophilic polyurethane matrix using a neutral solvent (dimethyl sulfoxide, or DMSO), they created a stable, high-viscosity ink suitable for precision printing. During post-print heating, the DMSO decomposes to form an acidic environment, which removes the oxide layer on the gallium particles. This triggers the particles to coalesce into electrically conductive networks with tunable mechanical properties.
The resulting printed circuits exhibit fine feature sizes (~50 μm), high conductivity (2.27 × 10⁶ S/m), and a stiffness modulation ratio of up to 1,465 – allowing the material to shift from plastic-like rigidity to rubber-like softness. Furthermore, the ink is compatible with conventional printing techniques such as screen printing and dip coating, supporting large-area and 3D device fabrication.
< Figure 2. Key features of the electronic ink. (i) High-resolution printing and multilayer integration capability. (ii) Batch fabrication capability through large-area screen printing. (iii) Complex three-dimensional structure printing capability through dip coating. (iv) Excellent electrical conductivity and stiffness control capability.>
The team demonstrated this technology by developing a multi-functional device that operates as a rigid portable electronic under normal conditions but transforms into a soft wearable healthcare device when attached to the body. They also created a neural probe that remains stiff during surgical insertion for accurate positioning but softens once inside brain tissue to reduce inflammation – highlighting its potential for biomedical implants.
< Figure 3. Variable stiffness wearable electronics with high-resolution circuits and multilayer structure comparable to commercial printed circuit boards (PCBs). Functions as a rigid portable electronic device at room temperature, then transforms into a wearable healthcare device by softening at body temperature upon skin contact.>
“The core achievement of this research lies in overcoming the longstanding challenges of liquid metal printing through our innovative technology,” said Professor Jeong. “By controlling the ink’s acidity, we were able to electrically and mechanically connect printed gallium particles, enabling the room-temperature fabrication of high-resolution, large-area circuits with tunable stiffness. This opens up new possibilities for future personal electronics, medical devices, and robotics.”
< Figure 4. Body-temperature softening neural probe implemented by coating electronic ink on an optical waveguide structure. (Left) Remains rigid during surgery for precise manipulation and brain insertion, then softens after implantation to minimize mechanical stress on the brain and greatly enhance biocompatibility. (Right) >
This research was published in Science Advances under the title, “Phase-Change Metal Ink with pH-Controlled Chemical Sintering for Versatile and Scalable Fabrication of Variable Stiffness Electronics.” The work was supported by the National Research Foundation of Korea, the Boston-Korea Project, and the BK21 FOUR Program.
2025.06.04 View 12967 -
Professor Hyun Myung's Team Wins First Place in a Challenge at ICRA by IEEE
< Photo 1. (From left) Daebeom Kim (Team Leader, Ph.D. student), Seungjae Lee (Ph.D. student), Seoyeon Jang (Ph.D. student), Jei Kong (Master's student), Professor Hyun Myung >
A team of the Urban Robotics Lab, led by Professor Hyun Myung from the KAIST School of Electrical Engineering, achieved a remarkable first-place overall victory in the Nothing Stands Still Challenge (NSS Challenge) 2025, held at the 2025 IEEE International Conference on Robotics and Automation (ICRA), the world's most prestigious robotics conference, from May 19 to 23 in Atlanta, USA.
The NSS Challenge was co-hosted by HILTI, a global construction company based in Liechtenstein, and Stanford University's Gradient Spaces Group. It is an expanded version of the HILTI SLAM (Simultaneous Localization and Mapping)* Challenge, which has been held since 2021, and is considered one of the most prominent challenges at 2025 IEEE ICRA.*SLAM: Refers to Simultaneous Localization and Mapping, a technology where robots, drones, autonomous vehicles, etc., determine their own position and simultaneously create a map of their surroundings.
< Photo 2. A scene from the oral presentation on the winning team's technology (Speakers: Seungjae Lee and Seoyeon Jang, Ph.D. candidates of KAIST School of Electrical Engineering) >
This challenge primarily evaluates how accurately and robustly LiDAR scan data, collected at various times, can be registered in situations with frequent structural changes, such as construction and industrial environments. In particular, it is regarded as a highly technical competition because it deals with multi-session localization and mapping (Multi-session SLAM) technology that responds to structural changes occurring over multiple timeframes, rather than just single-point registration accuracy.
The Urban Robotics Lab team secured first place overall, surpassing National Taiwan University (3rd place) and Northwestern Polytechnical University of China (2nd place) by a significant margin, with their unique localization and mapping technology that solves the problem of registering LiDAR data collected across multiple times and spaces. The winning team will be awarded a prize of $4,000.
< Figure 1. Example of Multiway-Registration for Registering Multiple Scans >
The Urban Robotics Lab team independently developed a multiway-registration framework that can robustly register multiple scans even without prior connection information. This framework consists of an algorithm for summarizing feature points within scans and finding correspondences (CubicFeat), an algorithm for performing global registration based on the found correspondences (Quatro), and an algorithm for refining results based on change detection (Chamelion). This combination of technologies ensures stable registration performance based on fixed structures, even in highly dynamic industrial environments.
< Figure 2. Example of Change Detection Using the Chamelion Algorithm>
LiDAR scan registration technology is a core component of SLAM (Simultaneous Localization And Mapping) in various autonomous systems such as autonomous vehicles, autonomous robots, autonomous walking systems, and autonomous flying vehicles.
Professor Hyun Myung of the School of Electrical Engineering stated, "This award-winning technology is evaluated as a case that simultaneously proves both academic value and industrial applicability by maximizing the performance of precisely estimating the relative positions between different scans even in complex environments. I am grateful to the students who challenged themselves and never gave up, even when many teams abandoned due to the high difficulty."
< Figure 3. Competition Result Board, Lower RMSE (Root Mean Squared Error) Indicates Higher Score (Unit: meters)>
The Urban Robotics Lab team first participated in the SLAM Challenge in 2022, winning second place among academic teams, and in 2023, they secured first place overall in the LiDAR category and first place among academic teams in the vision category.
2025.05.30 View 16573 -
KAIST Captures Protein Reaction in Just Six Milliseconds
Understanding biomolecular processes - such as protein-protein interactions and enzyme-substrate reactions that occur on the microseconds to millisecond time scale is essential for comprehending life processes and advancing drug development. KAIST researchers have developed a method for freezing and analyzing biochemical reaction dynamics within a span of just a few milliseconds, marking a significant step forward in better understanding complex biological reactions.
< Photo. (From left) Professor Jin Young Kang and Haerang Hwang of the Integrated Master's and Doctoral Program of the Department of Chemistry, along with Professor Wonhee Lee of the Department of Physics >
KAIST (represented by President Kwang Hyung Lee) announced on the 24th of March that a joint research team led by Professor Jin Young Kang from the Department of Chemistry and Professor Wonhee Lee from the Department of Physics has developed a parylene-based thin-film microfluidic mixing-and-spraying device for ultra-fast biochemical reaction studies.
*Parylene: A key material for microfluidic devices used to observe protein dynamics at ultra-high speeds. It can be fabricated into a few micrometer-thick films, which can be used in making a spray nozzle for microfluidic devices.
This research overcomes the limitations of the existing time-resolved cryo-electron microscopy (TRCEM) method by reducing sample consumption to one-third of the conventional amount while improving the minimum time resolution—down to just six milliseconds (6 ms).
TRCEM is a technique that rapidly freezes protein complexes during intermediate reaction stages under cryogenic conditions, which allows researchers to analyze their structures. This approach has gained significant attention recently for its ability to capture transient biochemical events.
< Figure 1. Time-resolved cryo-EM (TRCEM) technique using microfluidic channels. In order to capture the intermediate structure of biomolecules during a biochemical reaction over time, biomolecules and reaction substrates are mixed in a microfluidic channel, and then sprayed on a grid after a certain reaction time and frozen in liquid ethane to prepare a cryo-EM sample. This can then be analyzed by cryo-EM to observe the structural changes of proteins over time. >
Transient intermediate structures of protein complexes could not be captured by traditional cryo-electron microscopy due to their extremely short lifespans. Although several TRCEM techniques have been developed to address this issue, previous methods were hindered by large sample consumption and limited time resolution. To overcome these challenges, the KAIST team developed a new mixing-and-spraying device using ultra-thin parylene films. The integrated design of the device further enhanced the precision and reproducibility of experiments.
< Figure 2. TRCEM grid fabrication setup using a parylene-based thin-film microfluidic device and actual appearance of the device. You can see that a thin-film parylene channel is inserted into the injection nozzle. The integration of the reaction channel and the injection nozzle allowed the residence time in the device to be reduced to at least 0.5 ms. >
“This research makes TRCEM more practical and paves the way for diverse applications of the parylene thin-film device in structural biology, drug development, enzyme reaction studies, and biosensor research.” Professor Jin Young Kang explained, emphasizing the significance of the study.
Professor Wonhee Lee added, “The team aims to continue this research, focusing on improvement of the technique to achieve higher time resolution with minimal sample consumption.”
< Figure 3. Comparison of the spraying patterns of the parylene mixing-jet device and the conventional mixing-jet device and the filament length in the resulting RecA-ssDNA filament formation reaction. It was shown that the thin film spray nozzle structure affects the uniformity and accuracy of the final reaction time. >
The research findings, with Haerang Hwang (a graduate student in the integrated master's and Ph.D. program in the Department of Chemistry) as the first author, were published online on January 28, 2025, in the international journal Advanced Functional Materials. (Paper Title: “Integrated Parylene-Based Thin-Film Microfluidic Device for Time-Resolved Cryo-Electron Microscopy”, DOI: doi.org/10.1002/adfm.202418224)
This research was supported by the National Research Foundation of Korea (NRF), the Samsung Future Technology Development Program, and the CELINE consortium.
2025.03.24 View 11149 -
KAIST Captures Hot Holes: A Breakthrough in Light-to-Electricity Energy Conversion
When light interacts with metallic nanostructures, it instantaneously generates plasmonic hot carriers, which serve as key intermediates for converting optical energy into high-value energy sources such as electricity and chemical energy. Among these, hot holes play a crucial role in enhancing photoelectrochemical reactions. However, they thermally dissipate within picoseconds (trillionths of a second), making practical applications challenging. Now, a Korean research team has successfully developed a method for sustaining hot holes longer and amplifying their flow, accelerating the commercialization of next-generation, high-efficiency, light-to-energy conversion technologies.
KAIST (represented by President Kwang Hyung Lee) announced on the 12th of March that a research team led by Distinguished Professor Jeong Young Park from the Department of Chemistry, in collaboration with Professor Moonsang Lee from the Department of Materials Science and Engineering at Inha University, has successfully amplified the flow of hot holes and mapped local current distribution in real time, thereby elucidating the mechanism of photocurrent enhancement.
The team designed a nanodiode structure by placing a metallic nanomesh on a specialized semiconductor substrate (p-type gallium nitride) to facilitate hot hole extraction at the surface. As a result, in gallium nitride substrates aligned with the hot hole extraction direction, the flow of hot holes was amplified by approximately two times compared to substrates aligned in other directions.
To fabricate the Au nanomesh, a polystyrene nano-bead monolayer assembly was first placed on a gallium nitride (p-GaN) substrate, and then the polystyrene nano-beads were etched to form a nanomesh template (Figure 1A). Then, a 20 nm thick gold nano-film was deposited, and the etched polystyrene nano-beads were removed to realize the gold nano-mesh structure on the GaN substrate (Figure 1B). The fabricated Au nanomesh exhibited strong light absorption in the visible range due to the plasmonic resonance effect (Figure 1C). >
Furthermore, using a photoconductive atomic force microscopy (pc-AFM)-based photocurrent mapping system, the researchers analyzed the flow of hot holes in real time at the nanometer scale (one hundred-thousandth the thickness of a human hair). They observed that hot hole activation was strongest at "hot spots," where light was locally concentrated on the gold nanomesh. However, by modifying the growth direction of the gallium nitride substrate, hot hole activation extended beyond the hot spots to other areas as well.
Through this research, the team discovered an efficient method for converting light into electrical and chemical energy. This breakthrough is expected to significantly advance next-generation solar cells, photocatalysts, and hydrogen production technologies.
Professor Jeong Young Park stated, "For the first time, we have successfully controlled the flow of hot holes using a nanodiode technique. This innovation holds great potential for various optoelectronic devices and photocatalytic applications. For example, it could lead to groundbreaking advancements in solar energy conversion technologies, such as solar cells and hydrogen production. Additionally, the real-time analysis technology we developed can be applied to the development of ultra-miniaturized optoelectronic devices, including optical sensors and nanoscale semiconductor components."
The study was led by Hyunhwa Lee (PhD., KAIST Department of Chemistry) and Yujin Park (Postdoc Researcher, University of Texas at Austin Department of Chemical Engineering) as co-first authors and Professors Moonsang Lee (Inha University, Department of Materials Science and Engineering) and Jeong Young Park (KAIST, Department of Chemistry) serving as corresponding authors. The research findings were published online in Science Advances on March 7.
(Paper Title: “Reconfiguring hot-hole flux via polarity modulation of p-GaN in plasmonic Schottky architectures”, DOI: https://www.science.org/doi/10.1126/sciadv.adu0086)
This research was supported by the National Research Foundation of Korea (NRF).
2025.03.17 View 10389