- An artificial tactile neuron device that quickly and accurately converts the stiffness of a substance. - Combining with AI technology enables learning of the stiffness levels and distributions of the tumor, suggesting the possibility of cancer diagnosis. The stiffness levels and distributions of various biological materials reflect disease-related information, from cells to tissues. For example, malignant breast tumors are usually stiffer and have a more irregular shape than benign breast tumors. Ultrasound elastography can non-invasively determine the degree and shape of the tissue stiffness and is used for diagnosing breast cancer owing to its low cost. However, the opinion of an experienced expert is essential for interpreting ultrasound elastography images, but different experts differ in accuracy. The president of the Korea Institute of Science and Technology (KIST), Mr. Seok-Jin Yoon, announced that Dr. Hyunjung Yi's team at the spin convergence research center and Suyoun Lee, the director of the Center for Neuromorphic Engineering, had developed a simple but highly accurate disease diagnosis technology by combining tactile neuron devices with artificial neural network learning methods. Unlike the previously reported artificial tactile neuron devices, this tactile neuron device can determine the stiffness of objects. Neuromorphic technology is a research field that aims to emulate the human brain's information processing method, which is capable of high-level functions while consuming a small amount of energy using electronic circuits. Neuromorphic technology is gaining attention as a new data processing technology fit for AI, IoT, and autonomous driving, requiring the real-time processing of complex and vast information. Sensory neurons receive external stimuli through sensory receptors and convert them into electrical spike signals. Here, the generated spike pattern varies based on the external stimulus information. For example, higher stimulus intensity causes higher generated spike frequency. The research team developed an artificial tactile neuron device with a simple structure that combines a pressure sensor and an ovonic threshold switch device to produce such sensory neuron characteristics. Applying pressure to the pressure sensor causes the sensor's resistance to decrease and the connected ovonic switch element's spike frequency to change. The developed artificial tactile neuron device is a high-response, high-sensitivity device that allows the pressing force to generate faster electrical spikes while improving the pressure sensitivity, which focuses on the fact that stiffer materials result in faster pressure sensing when pressed. The electrical spike duration (or 1/frequency) generated by the developed device is less than 0.00001 s, which is more than 100,000 times faster than the several seconds it usually takes to press an object. Additionally, while the existing devices could detect a low pressure (approximately 20 kPa, similar to a force of light pressing) with a spike frequency change of 20 to 40 Hz, the developed device can detect the low pressure with spike frequency changes of 1.2 MHz. This allows real-time conversion of changes in the pressing force into spikes. To deploy the developed device to actual disease diagnosis, the research team used elastography images of malignant and benign breast tumors and utilized a spiking neural network learning method. Each pixel of the color-coded ultrasound elastography image which is correlated with the stiffness of the imaged material was converted into a spike frequency change value and used for training the AI. As a result, it was possible to determine the malignancy of a breast tumor with up to 95.8% accuracy. The KIST research team stated, "the developed artificial tactile neuron technology is capable of detecting and learning mechanical properties with a simple structure and method." The team added, "Through follow-up research, it will be possible to solve the noise reflection issue, which is a disadvantage of ultrasound elastography if artificial tactile neurons can collect an object's elastography image obtainable using ultrasound elastography." The team also expects the device to be helpful in low-power and high-accuracy disease diagnosis and applications such as robotic surgery where a surgical site needs to be quickly determined in an environment humans cannot directly contact." - Image The research results are published as an inside back cover paper in Advanced Materials.

- Discovery of dispersing solvent parameters affecting ionomer microporous structure - Performance improvement of proton-exchange membrane hydrogen fuel cells under high-temperature and non-humidified conditions A hydrogen fuel cell, which is a device that generates electrical energy through the reaction of hydrogen and oxygen in air, is gaining increasing attention as an eco-friendly power-generating device that do not emit pollutants. Among the various hydrogen fuel cells, proton-exchange membrane fuel cells (PEMFCs), which use ion-exchangeable polymer membranes as electrolytes, are relatively lightweight and have a faster start-up time. Owing to these characteristics, they are actively studied as a power source for homes and automobiles. Owing to their high electrochemical reaction rates and strong resistance to impurities at high operating temperatures, PEMFCs are ideal for applications in high-performance transportation, such as trucks, subways, trains, airplanes, and ships. However, a separate cooling system is required at high temperatures (>100 °C) to prevent ionic conductivity reduction triggered by evaporation in polymers. The weight added by cooling systems decreases the efficiency of PEMFCs. To use PEMFCs without a cooling system, high-temperature performance improvement and (80–200 ℃) non-humidification conditions are essential. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that Dr. Sung-Soo Lee’s team at the Material Structure Control Research Center, KIST, South Korea, and Dr. Yu-Seung Kim’s team at the Los Alamos Research Center (LANL), the U.S, have jointly developed a platform for controlling the microporous structure of ionomers, which is the key to improving the PEMFC performance. When polymer-containing phosphonic acid (RPO3H2) and polymer-containing sulfonic acid (RSO3H) combine, hydrogen from the sulfonic acid, which has a higher acid strength, is transferred to the phosphonic acid, thereby forming a protonated phosphonic acid ionomer. Using such a composite ionomer enables waterless ionic conduction, resulting in an increased performance of hydrogen fuel cells, even under high-temperature and non-humidified conditions. Further performance improvement can be expected through increased usage of reactive gases, such as hydrogen and oxygen. The KIST and LANL joint research team induced the accessibility of reactive gases by manipulating a composite ionomer to obtain a microporous structure. The team discovered the dependency of the composite ionomer’s microporous structure on the solvent in which it is dispersed, as well as a direct correlation between the dispersion solvent’s pKa (acid strength) and the phosphonic acid ionomer’s microporous structure. Subsequently, a performance evaluation of a high-temperature-hydrogen fuel cell confirmed that the composite ionomer’s microporous structure positively affected the performance of fuel cells. Dr. Sung-Soo Lee of KIST said, “The achievement is in discovering how important ionomer dispersion solvent pKa is in high-temperature-hydrogen fuel cells.” He revealed the significance of the study, adding, “We have expanded the use of hydrogen fuel cells from small transportation to bigger mobility such as trucks and ships.” This research was performed as part of the Advanced Research Projects Agency-Energy of the US Department of Energy, the Material Innovation Lead Project of the Ministry of Science and ICT (Minister Jong-Ho Lee), and the major projects of KIST. The research results are published in ‘ACS Energy Letters’ (IF:23.101, JCR top 3.302%). [Figure 1] The appearance of the protonated phosphonic acid film affected by the ionomer dispersion solvent, and the films’ microstructures and elemental analyses examined using electron microscopy. The red regions denote sulfonic acid (S) groups, and blue regions denote phosphonic acid (P) groups. The visible light transmittance (T%) and STEM-EDX [A2] at 550 nm, which are related to ionomer compatibility, are shown. A higher visible light transmittance results in increased film transparency. [Figure 2] MEAs’ power density treated with various dispersion solvents. MEA molded with a highly porous organic solvent displays a maximum power density.

- Development of polymer additives to solve the performance degradation of large-area solar cells based on the solution process. - Future expectations regarding solar cell technology commercialization that can be applied in printing technology Solar cell technology is a prominent clean energy source. In particular, organic solar cells, part of the third generation of solar cells, are gaining attention as a core technology for urban solar ray energy generation as they can be printed and applied to exterior walls or glass windows of buildings. However, the photoactive area that absorbs sunlight and converts it to electricity remains significantly smaller than 0.1 cm². Additionally, commercialization is obstructed by performance and reproducibility problems that occur when expanding the cell area to several m2 where practical energy supply levels are available. A research team led by Dr. Hae Jung Son of the Advanced Photovoltaics Research Center at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon) discovered the factors causing performance degradation in large-area organic solar cells and announced the development of a new polymer additive material for large-area, organic solar cell technology development. The research team focused on the photoactive layer’s compositional form in organic solar cells and the solution process, which is a part of the organic solar cell manufacturing process. The spin coating method, a solution process mainly used in the laboratory research stage, creates a uniform photoactive layer mixture as the solvent evaporates rapidly while the substrate rotates at a high speed. However, the large-area, continuous solution process designed for industrial use caused solar cell performance deterioration because the solar cell material solution’s solvent evaporation rate was too slow. Consequently, unwanted aggregation between the photoactive materials can be formed. The research team developed a polymer additive that can prevent this phenomenon by interacting with materials prone to aggregate. As a result, ternary photoactive layers containing polymer additives were fabricated to prevent aggregation in photoactive layers. Additionally, owing to possible nano-level structure control, solar cell performance improvements and stability security are acquired against light-induced temperature increases during solar cell operation. A 14.7% module efficiency was achieved, resulting in a 23.5% performance increase compared to that of the conventional binary system. Efficiency and stability were simultaneously demonstrated by maintaining over 84% initial efficiency for 1,000 hours, even in an 85℃ heated environment. KIST’s Dr. Son stated, “We have gotten closer to organic solar cell commercialization by proposing the core principle of a solar cell material capable of high-quality, large-area solution processing,” further expressing that “commercialization through follow-up research will make eco-friendly self-sufficient energy generation possible that is easily applicable to exterior building walls and automobiles and also utilized as an energy source for mobile and IoT devices.” - Image (left) high-efficiency, high-stability, organic solar module incorporating ternary photoactive layers. (right) Performance of the high-efficiency, high-stability, organic solar module incorporating ternary photoactive layers

- Small-molecule activation of innate immunity induces the infiltration of immune cells into cancer cells - Expected applications include various combination therapies for immuno-oncology Innovations in cancer immunotherapy have achieved clinical success by considerably increasing the survival rate of patients undergoing cancer treatment. However, there still exists an unmet medical need due to the low response rate to checkpoint inhibitors caused by the low immune reactivity of cancer cells in “cold” tumors. In their efforts to turn “cold” tumors into “hot” tumors, many global pharmaceutical companies have been focusing on utilizing the innate immune regulatory protein known as STING to increase the immunoreactivity of tumors and the infiltration of immune cells into the tumor microenvironment (TME). However, since clinical trials on the first STING agonist, ADU-S100, were suspended in 2020, there is an urgent need to develop new STING activators. Under these circumstances, a research team led by Dr. Sanghee Lee of the Brain Science Institute at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon), and Dr. Hyejin Kim of the Infectious Diseases Therapeutic Research Center at the Korea Research Institute of Chemical Technology (KRICT; President: Mihye Yi) announced the development of a new small-molecule STING agonist. Once the STING agonist was stimulated by a compound, it induced the secretion of cytokines such as interferons (IFNs) and activated an innate immune response mediated by T cells. The activated immune system altered the immune phenotype of the tumor, turning it from “cold” with a low reactivity to T cells to “hot” with a high reactivity, leading to the recruitment of T cells in the TME. In this study, compound administration effectively inhibited the growth of cancer cells in mice models. In particular, 20% of the treated group was found to be tumor-free as a result of the complete elimination of their tumors. Furthermore, immunological memory suppressed the growth of recurrent tumors without need for additional drug administration. Ultimately, no tumor growth was observed in the tumor-free group after the first treatment. Most of the existing STING agonists were subjected to intratumoral administration, which limited the broad application of cancer treatment, whereas the compound in this study was able to be administered by intravenous injection. In terms of further drug development, this agent is also able to be applied to combination cancer therapies and current standard treatments, such as radiation therapy, chemotherapy, and monotherapy. Dr. Lee stated, “Everyone dreams of vanquishing cancer; however, the development of cancer immunotherapeutics for ailments such as brain tumors is still limited. We hope that this study can provide the seeds for new therapeutic strategies for cancers where immunotherapy has had limited application.” Image Supplementary cover image of J. Med. A schematic diagram in which the substance developed in this study stimulates immune cells, activates an innate immune response, and induces cancer cell death. Chemical structure and mechanism of action of the STING agonist with the 4c compound developed in this study (left) and results and schematic diagram of anticancer efficacy in animal models (right).

- Dramatically improved the performance of 2D semiconductor devices by supressing the Fermi-level pinning phenomenon - Expected to speed up the commercialization of next-generation system technologies such as miniaturization of artificial intelligence systems To realize artificial intelligence systems and autonomous driving systems, which is often seen in movies, in everyday life, processors that function as the brain of computers must be able to process more data. However, silicon-based logic devices, which are essential components of computer processors, have limitations in that processing costs and power consumption increase as miniaturization and integration progress. To overcome these limitations, studies are being conducted on electronic and logic devices based on very thin two-dimensional semiconductors at an atomic layer level. However, it is more difficult to control the electrical properties through doping in two-dimensional semiconductors than in conventional silicon-based semiconductor devices. Thus, it has been technically difficult to implement various logic devices with two-dimensional semiconductors. The Korea Institute of Science and Technology (KIST; President: Seok-jin Yoon) announced that a joint research team led by Dr. Do Kyung Hwang of the Center for Opto-Electronic Materials and Devices and Professor Kimoon Lee of the Department of Physics at Kunsan National University (President: Jang-ho Lee), has succeeded in implementing two-dimensional semiconductor-based electronic and logic devices, whose electrical properties can be freely controlled by developing a new ultra-thin electrode material (Cl-SnSe2). The joint research team was able to selectively control the electrical properties of semiconductor electronic devices using Cl-doped tin diselenide (Cl-SnSe2), a two-dimensional electrode material. It was difficult to implement complementary logic circuits with conventional two-dimensional semiconductor devices because they only exhibit the characteristics of either N-type or P-type devices due to the Fermi-level pinning phenomenon. In contrast, if the electrode material developed by the joint research team is used, it is possible to freely control the characteristics of the N-type and P-type devices by minimizing defects with the semiconductor interface. In other words, a single device performs the functions of both N-type and P-type devices. Hence, there is no need to manufacture the N-type and P-type devices separately. By using this device, the joint research team successfully implemented a high-performance, low-power, complementary logic circuit that can perform different logic operations such as NOR and NAND. Dr. Hwang said that, “this development will contribute to accelerating the commercialization of next-generation system technologies such as artificial intelligence systems, which have been difficult to use in practical applications due to technical limitations caused by the miniaturization and high integration of conventional silicon semiconductor devices." He also anticipated that "the developed two-dimensional electrode material is very thin; hence, they exhibit high light transmittance and flexibility. Therefore, they can be used for next-generation flexible and transparent semiconductor devices." Image Operation results of the two-dimensional semiconductor device and logic device implemented by the joint research team Structure of the two-dimensional semiconductor electronic device implemented in this study (left) and its image captured through an electron microscope (right)

- New achievements of a durable cell mimic thin membrane structure - Tunable and controllable cell-like 3D shapes fabrication on a silicon substrate on-demand: New momentum for future biosensor In nature, the cell membrane has a unique function of protecting the internal from the external environment and communicating outside by sensing the external chemical or physical stimuli like the most precise biosensor for life. The cell membrane, which contains a hydrophilic part that is miscible well with water on the one side and a hydrophobic part that is not miscible well with water on the other, opens and closes ion channels like a water faucet and converts a physicochemical stimulus into an electrical signal which is then transmitted to cells. Active research worldwide on biosensors that can mimic the cell membrane’s excellent sensing has been suggested. However, till recently, the limited ability of an artificial cell membrane structure to only last a maximum of 5 days has been a hurdle. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that the research team led by Dr. Tae Song Kim of the Brain Science Institute has succeeded in developing an artificial cell membrane that can be kept stable for over 50 days on a silicon substrate. This is the longest time reported in the field. In addition to creating, in 2018, an artificial cell membrane lasting for five days, in 2019, Dr. Kim’s team demonstrated the transfer of a positive ion to the inside of a structure with an artificial cell membrane with a protein attached to the surface, confirming its biosensor application potential. However, the durability of at least one month is essential for life science research utilizing artificial cell membranes and the practical commercialization of biosensors. To extend the limit of 5 days of stability of an artificial cell membrane, the KIST research team focused on a material called block copolymer (BCP). A BCP is a macromolecule consisting of two or more blocks, which can be repeatedly aligned as a long row of blocks of counteracting properties that mimic the hydrophilic and hydrophobic nature of the human cell membrane. Dr. Kim’s research team developed a technology that regularly arranges tens of thousands of holes with a diameter of 8 μm (micrometer) on a silicon substrate and inserts a specific amount of BCP solution into each hole through surface treatment, and dries it. Then, a soap bubble-shaped, an elongated oval-shaped, or a thin tubular-shaped BCP double-layer structure is tunably created by applying an electric field between the upper plate electrode of the microfluidic channel and the lower silicon substrate. This process led to the discovery of the possibility of maintaining a structure with a specific shape depending on the concentration of the solution and the applied electric field and frequency. This suggests a means to freely control the size and shape of artificial cell membranes, from a sphere, like a soap bubble, to a cylinder, like a tube. The KIST research team finally created an artificial cell membrane that can be kept stable for over 50 days by filling the outside of a three-dimensional double-layered BCP structure with a porous hydrogel that exhibits excellent elasticity and resilience characteristics similar to that of a human body substance. In addition, an artificial organ structure was produced by replicating an epithelial cell in the small intestine, which consists of thousands of tubular structures (cilia) using a BCP double-layered structure, proving its usage potential as a material for artificial organs through binding with β-galactosidase. Dr. Kim from KIST said, “While global research on artificial cell membranes has been focusing on placing a two-dimensional planar structure on a silicon substrate, the team has succeeded in extending the stability period of an artificial cell membrane by more than ten times following the development of the first three-dimensional artificial cell membrane structure fabrication technology,” and added, “The research, which has presented a path for large area array fabrication of artificial cell membranes, is expected to further develop into a platform technology for biological functionality research that identifies the roles of ultra-sensitive biosensors resembling cell functions, drug screening for new drug development, and neurotransmitters and hormones in the brain.” Image Schematic diagram of manufacturing double-layer structures of various sizes and shapes by controlling the concentration and electric-field of the block copolymer (PBd-PEO) by applying electric fields to the upper and lower layers of the substrate Numerous fabricated spherical and tubular structures and a lateral confocal photomicrograph of a single structure Size distribution of each spherical and tubular structure

- Excellent gold recovery performance even under the coexistence of metal ions and suspended solids - Significant reduction in cost and time of the recovery process, mass production of materials, and repeated recycling is possible In South Korea, which relies on imports for 99.3% of metal resources, the per capita consumption of metal resources is the highest in the OECD (Organization for Economic Co-operation and Development), and consumption of precious metals in various industries such as renewable energy, healthcare, and semiconductors is increasing. Among the different precious metals, gold is in demand in various fields such as batteries, electric vehicles, and renewable energy in the electric and electronic industries but always acts as a big variable in the industry due to its limited availability and high cost. Thus, research on ‘urban mining,’ which extracts precious metals from waste, is being actively conducted around the world. However, most of the technologies for extracting high-purity gold using waste resources require large amounts of chemicals and high operating temperatures; therefore, it has environmental regulations and efficiency problems. A Korean research team has developed a technology that can dramatically increase the recovery rate of precious metals from waste. The research team comprising Dr. Jae Woo Choi and Dr. Kyung-Won Jung from the Center for Water Cycle Research at the Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) reported that they developed a gold recovery process with the world’s highest recovery efficiency of 99.9 % by developing a capsule-type material in which a polymeric shell surrounds a multi-layered internal structure. The developed material has the advantage of high recovery efficiency compared to conventional adsorption materials since the material traps gold ions inside the capsule for recovery. The material also has the advantage of preventing the clogging of the internal porous structure since the polymeric shell allows gold ions to penetrate while being impermeable to suspended solids present with gold. By introducing functional groups that react only with gold ions in the multi-layered internal structure, gold that has passed through the polymeric shell could be stably recovered even with the coexistence of 14 types of ions and 3 types of suspended solids. Capsule-type material can be produced through a continuous process based on the solvent exchange method, and its efficiency and stability were demonstrated by maintaining a recovery performance of 99.9% or more even when the material was reused 10 times. Dr. Choi and Dr. Jung stated that, “The material developed through this research solves the problems of conventional materials developed for the recovery of precious metals. Moreover, it can be immediately applied to related industrial processes as they can be easily synthesized in large quantities". They also stated, “Through this study, it was evident that the chemical properties and morphology of the recovered material could also play a very important role in recovering metal resources from the water.” The lead author, Dr. Youngkyun Jung of KIST said that, “The results of this research are expected to serve as a basis for the development of the first eco-friendly process in Korea that can selectively recover and refine metal resources from waste and precious metal scraps generated in various industries, such as automobiles and petrochemicals.” Image Manufacturing process and the physical/chemical structures of gold recovery material Gold recovery concept of material (left) and its performance (right) (From left) gold-containing waste liquid, a capsule-type material wrapped in a circular polymeric shell (white) developed by KIST researchers to recover gold in an eco-friendly manner, gold extracted through the recovery process, and recovered gold refined into high-purity gold

- Development of a ‘Nanomachines’ that penetrates and kills cells via mechanical molecular movements - Selective penetration of cancer cells using a latch molecule released near cancer cells Proteins are involved in every biological process, and use the energy in the body to alter their structure via mechanical movements. They are considered biological 'nanomachines' because the smallest structural change in a protein has a significant effect on biological processes. The development of nanomachines that mimic proteins has received much attention to implement movement in the cellular environment. However, there are various mechanisms by which cells attempt to protect themselves from the action of these nanomachines. This limits the realization of any relevant mechanical movement of nanomachines that could be applied for medical purposes. The research team led by Dr. Youngdo Jeong from the Center for Advanced Biomolecular Recognition at the Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) has reported the development of a novel biochemical nanomachine that penetrates the cell membrane and kills the cell via the molecular movements of folding and unfolding in specific cellular environments, such as cancer cells, as a result of a collaboration with the teams of Prof. Sang Kyu Kwak from the School of Energy and Chemical Engineering and Prof. Ja-Hyoung Ryu from the Department of Chemistry at the Ulsan National Institute of Science and Technology (UNIST, President Yong Hoon Lee), and Dr. Chaekyu Kim of Fusion Biotechnology, Inc. The joint research team focused on the hierarchical structure of proteins, in which the axis of the large structure and the mobile units are hierarchically separated. Therefore, only specific parts can move around the axis. Most existing nanomachines have been designed so that the mobile components and axis of the large structure are present on the same layer. Thus, these components undergo simultaneous movement, which complicates the desired control of a specific part. A hierarchical nanomachine was fabricated by synthesizing and combining 2 nm-diameter gold nanoparticles with molecules that can be folded and unfolded based on the surrounding environment. This nanomachine was comprised of mobile organic molecules and inorganic nanoparticles to function as large axis structures, and defined movement and direction in such a manner that upon reaching the cell membrane, it resulted in a mechanical folding/unfolding movement that led to the nanomachine directly penetrating the cell, destroying the organelles, and inducing apoptosis. This new method directly kills cancer cells via mechanical movements without anticancer medication, in contrast to the capsule-type nanocarriers that deliver therapeutic drugs. Subsequently, a latch molecule was threaded onto the nanomachine to control the mechanical movement to selectively kill cancer cells. The threaded latch molecule was designed to be released only in a low pH environment. Therefore, in normal cells with a relatively high pH (approximately 7.4), the movements of nanomachine was restricted and they could not penetrate the cell. However, at the low pH environment around cancer cells (approximately 6.8), the latch molecules were untied, inducing mechanical movement and cell penetration. Dr. Jeong said, “The developed nanomachine was inspired by proteins that perform biological functions by changing their shape based on their environment. We propose a novel method of directly penetrating cancer cells to kill them via the mechanical movements of molecules attached to nanomachines without drugs. This could be a new alternative to overcome the side effects of existing chemotherapy.” Image Nanomachine, developed by KIST-UNIST joint research team, which selectively penetrates and kills cancer cells, and its mechanism of action The nanomachine directly penetrates cancer cells and kills them by destroying their organelles via mechanical movements of the molecule.

- Identification of the operating mechanism of cobalt-based single-atomic catalyst and development of a mass production process - Utilization for catalyst development in various fields including fuel cells, water electrolysis, solar cells, and petrochemical Fuel cell electric vehicles (FCEVs) are an eco-friendly means of transportation that will replace internal combustion locomotives. FCEVs offer several advantages such as short charging time and long mileage. However, the excessive cost of platinum used as a fuel cell catalyst leads to limited supply of FCEVs. There has been extensive research on non-precious metal catalysts such as iron and cobalt to replace platinum; however, it is still challenging to find substitutes for platinum due to low performance and low stability of non-precious metal catalysts. The research team led by Dr. Sung Jong Yoo of the Hydrogen·Fuel Cell Research Center at Korea Institute of Science and Technology (KIST, President Seok Jin Yoon) conducted joint research with professor Jinsoo Kim of Kyung Hee University and professor Hyung-Kyu Lim of Kangwon National University; they announced that they have developed a single atomic cobalt-based catalyst with approximately 40% improved performance and stability compared to contemporary cobalt nanoparticle catalysts. Conventional catalysts are typically synthesized via pyrolysis, wherein transition metal precursors and carbon are mixed at 700？1000℃. However, due to metal aggregation and a low specific surface area, the catalysts obtained through this process had a limited activity. Accordingly, researchers have focused on synthesizing single-atomic catalysts; however, previously reported single-atomic catalysts can only be produced in small quantities because the chemical substances and synthesis methods used varied depending on the type of the synthesized catalyst . Therefore, research has focused on performance improvement of the catalyst rather than the manufacturing process. To address this problem, the spray pyrolysis method was implemented using an industrial humidifier. Droplet-shaped particles were obtained by rapidly heat-treating the droplets obtained from a humidifier. This can enable mass production through a continuous process, and any metals can be easily produced into particles. The materials used for the synthesis of metal particles should be water-soluble because the particles are made through an industrial humidifier. It was confirmed that the cobalt-based single-atomic catalysts developed through this process exhibit excellent stability as well as fuel cell performance and are 40% superior compared to conventional cobalt catalysts. Cobalt-based catalysts also cause side reactions in fuel cells; however, computational science has shown that catalysts manufactured via spray pyrolysis lead to forward reactions in fuel cells. Dr. Yoo clarified, “Through this research, a process that can enable considerable improvement in the mass production of cobalt-based single-atomic catalysts has been developed, and the operating mechanism of cobalt-based catalysts has been elucidated via close analyses and computational science. These results are expected to serve as indicators for future research on cobalt catalysts.” They also added, “We plan to expand the scope of future research to explore not only catalysts for fuel cells, but also environmental catalysts, water electrolysis, and battery fields.” Image (a) single-atomic catalyst synthesis process using humidifier method, (b) SEM image, (c) cobalt element mapping image, (d) high-resolution STEM image of cobalt single-atomic catalyst (Left) Catalyst performance reduction rate and metal dissolution rate after 100-h evaluation; (right) comparison with existing literature of cobalt- and iron-based catalysts

- First proof of information preservation relation in quantum measurement - Expected to be used for optimally designing quantum computing and quantum cryptography protocols with quantum measurements ‘Schr？dinger’s cat’ is a thought experiment designed to explain ‘quantum superposition’ and ‘quantum measurement,’ which are the core characteristics of quantum physics. In this experiment, the cat inside the box can be both alive and dead at the same time (quantum superposition), and its state (dead or alive) is decided the moment the box is opened (measured). Such quantum superposition and measurement are not only the foundation of quantum physics, but also guarantee the safety of quantum computing and cryptography. The research team, comprising Drs. Seongjin Hong, Hyang-Tag Lim, and Seung-Woo Lee from the Center for Quantum Information at the Korea Institute of Science and Technology (KIST, President Seok Jin Yoon), derived and verified the information preservation relation for the first time in quantum measurement. This strengthens the security of quantum information technologies even in weak quantum measurement realm. Opening the box (quantum measurement) accommodating the cat to obtain information on whether it is dead or alive changes the initial condition of the cat being both dead and alive at the same time (quantum superposition) to just being either dead or alive. In other words, the cat is dead from the moment we obtain the information of its ‘being dead,’ or is alive the moment we obtain the information of its ‘being alive.’ Due to the irreversibility of quantum measurements, the cat’s state cannot be reversed. However, what would have happened if the measurement had not been done completely, i.e., if the box had been opened a little bit only to reveal the cat’s tail? This event is called ‘weak measurement’ in quantum mechanics. In this case, complete information on the cat’s state cannot be obtained, and the cat’s state can be reverted to its initial state using measurement ‘reversal.’ Therefore, establishing a ‘relation of quantum information preservation’ by considering the amount of obtained, disturbed and reversible information has been a challenge in quantum physics and also an important task to ensure the security of quantum technology. The research team theoretically derived an information preservation relation considering the reversing probability along with the existing relations of ‘information gain’ and ‘state disturbance.’ This information preservation relation was experimentally verified using linear optical elements such as waveplates and polarizers to implement ‘weak measurement’ and ‘reversing operations’ and by applying them to a three-dimensional quantum state realized by a single photon. This information preservation relation reveals that obtaining more information on a quantum state by increasing the intensity of measurement disturbs the quantum state more. At the same time, it is also shown that the probability of reversing the disturbed state to its initial state before weak measurement becomes lower. It should be noted that if it were possible to reverse a disturbed quantum state to its initial state, then the safety of quantum cryptography may be not guaranteed. Drs. Hong and Lim, who led the experiment of this study, and Dr. Lee, who led the theory, said that “this is the result of perfectly establishing that quantum technology is secure in principle by proving that the total amount of information of a quantum state cannot be increased even through measurement”, and that they “expect this to be applied as an optimization technology for quantum computing, quantum cryptography, and quantum teleportation”. Image Quantum information preservation relation and schematic diagram of quantum states subjected to ‘weak measurement’ and ‘reverting operations’ (G: information obtained by measurement, F: information remaining in quantum state after measurement, R: probability of successful reversion) Selected as cover of Physical Review Letters