에너지화학공학과

Research 2026년 10월 01일 목요일

Beyond Ideal Conditions

《Editor's Note: Research works by controlling variables. But the problems it ultimately confronts rarely offer the same courtesy. Heat gets into storage tanks. Expertise shifts from one question to the next. Satellite images arrive out of season. Materials face conditions far beyond the laboratory norm. The obvious response is to restore control —keep the heat out, remove the variation, recreate the ideal test. But what happens when ideal conditions are no longer an option? This month, UNIST researchers took that question in different directions. Some intervene before a problem takes hold —or after a familiar line of defense has failed. Others design for rather variation than uniformity, or put promising results to more demanding tests. The approaches differ, but the underlying shift is the same —rather than trying to restore control, they rethink the solution around what actually changes.》 CHANGE WHERE YOU INTERVENE “Sometimes the best place to solve a problem is not where it appears.” For atomically thin semiconductors, contamination during fabrication can be especially difficult to undo. Plasma exposure changes the chemistry of photoresist, causing residue to bind more strongly to MoS₂. Aggressive cleaning, meanwhile, risks damaging the material itself. Rather than trying to remove the residue afterward, UNIST researchers placed a removable, 5-nanometer metal layer over the semiconductor before patterning, preventing the contamination from reaching its surface. The resulting transistors showed roughly a tenfold reduction in contact resistance and a similar increase in on-current. Liquid hydrogen presents the problem from the opposite direction. Even well-insulated tanks cannot keep heat out indefinitely. Instead of treating insulation as the only line of defense, researchers investigated whether metal-organic frameworks could capture evaporating hydrogen after heat enters the tank and slow the buildup of pressure. In modeling, IRMOF-20 preserved about 97 percent of the volumetric capacity of liquid hydrogen while extending the projected storage period from roughly 64 to 221 days. One solution acts before the problem reaches the material: the other takes effect after a familiar line of defense has been breached. In both cases, changing where researchers intervene changes what can be done about the problem. ■ New Process Shields 2D Semiconductors from Fabrication Residue (Small) ■ Rethinking Liquid Hydrogen Storage with MOFs (Nature Communications) WORK WITH WHAT CHANGES “When the world refuses to stay consistent, the method has to change with it.” Personalization gets harder when expertise refuses to stay fixed. A person who is an expert in one subject may be a novice in another—and even within the same field, expertise can change from question to question. ExPerT responds to that variation rather than smoothing it away. By combining the semantics of each query with patterns in a user's typing behavior, the framework estimates expertise for individual questions and adjusts the detail, terminology, and complexity of its answers accordingly. In a study involving 40 participants and 1,270 queries, it reduced expertise-estimation error by 65.7 percent compared with the strongest baseline. For wildfire assessment, the changing conditions are not the user but the landscape. Satellite images taken before and after a fire may come from different seasons, allowing natural changes in vegetation to be mistaken for fire damage. Instead of requiring seasonally matched images, UNIST researchers use nearby unburned vegetation to estimate seasonal change and correct the comparison. Across 12 US wildfires, it achieved a correlation of 0.72 with field observations using seasonally mismatched imagery—nearly matching the 0.73 obtained with images from similar seasons. One method adapts to knowledge that changes from question to question—the other accounts for landscapes that change with the season. Neither requires the variation to disappear before the analysis can begin. ■ AI Personalization Adapts Answers to What Users Know (ACL '26) ■ Assessing Wildfire Burn Severity Across Seasons (Remote Sens. Environ.) TEST WHAT HOLDS UP “A promising result means more when it holds up under a more demanding test.” Perovskite solar cells (PSCs) have reached impressive efficiencies, but performance under controlled conditions tells only part of the story. UNIST researchers developed a molecular interface that delivered a certified power-conversion efficiency of 26.37 percent, then subjected the cells to repeated swings between −100°C and +100°C. After 16 cycles, they retained about 91 percent of their initial efficiency—putting their stability to a far more demanding test. AI highlight detection faces a different gap between promising results and meaningful tests. Existing benchmarks have largely relied on videos lasting only a few minutes, even though real sports broadcasts can run for hours. SVHighlights closes the gap with 320 videos across eight sports and 640.18 hours of footage. Its videos average about two hours—roughly 30 to 60 times longer than those in existing datasets—allowing AI models to be evaluated under conditions much closer to the task they are meant to perform. One study subjects a material to extreme temperature swings, while the other tests AI against the scale of the task it is meant to perform. Both ask the same question: Does a promising result still hold when the test starts to resemble the challenge it is meant to meet? ■ PSCs Hold Up Under Extreme Temperature Swings (Joule) ■ AI Sports Highlight Detection to a More Realistic Test (ACM KDD '26) Explore the latest issue and follow 『The UNIST Brief』 on LinkedIn to stay updated. Subscribe via LinkedIn

Research 2026년 09월 29일 화요일

Less Than a Drop of Water Generates Electricity for Up to 45 Hours

Abstract Hydrovoltaic power generation offers a promising route for sustainable energy generation, yet existing systems typically rely on evaporation-driven flow or environmental moisture gradients, limiting device encapsulation and compact integration. Here, we introduce a confinement-induced ion-selective mechanism that enables sealed hydrovoltaic power generation from minimal water input. By engineering asymmetric nanochannel confinement in MXene/cellulose nanofiber (CNF) composites, localized hydration generates spatially distinct cation selectivity, establishing a persistent ion gradient and a confinement-dependent Donnan potential that drives capacitive charge accumulation. The harvested energy derives from substantial interfacial free energy released upon hydration of nanochannels with a high surface-to-volume ratio. Slow capillary migration then delays relaxation of the ion gradient, sustaining this charging and prolonging the resulting direct current (DC) output, without reliance on evaporation-driven flow or ambient humidity. Consequently, a single 3 µL water droplet enables stable DC output for up to 45 h. The device operates robustly under airflow (5–20 L min−1), relative humidity (17%–90%), and various electrolytes (tap water, seawater, and sweat), demonstrating humidity-insensitive, sealed operation. This confinement-governed hydrovoltaic framework expands the mechanistic understanding of water-enabled energy generation and provides a scalable platform for wearable and distributed electronics. A hydrovoltaic generator developed at UNIST can produce electricity for up to 45 hours from just 3 microliters (µL) of water, without relying on evaporation or ambient humidity. Led by Professor Hyunhyub Ko of the School of Energy and Chemical Engineering at UNIST, the research team developed a thin-film device that creates an ion imbalance within its own nanoscale channels. This allows the generator to operate while sealed, addressing a key limitation of hydrovoltaic systems that depend on evaporation or moisture in the surrounding air. Many hydrovoltaic devices rely on evaporation or environmental moisture to sustain electrical output, making their performance sensitive to humidity and airflow. The UNIST device instead generates electricity through the way water and dissolved ions move through channels built into the film itself. The film consists of stacked MXene nanosheets and cellulose nanofibers (CNFs). When water enters the film, one end swells while the other remains constrained, creating channels that gradually narrow from one side to the other. These narrowing channels interact differently with positively charged ions in the water, creating an uneven distribution of ions across the film. The resulting ion imbalance creates an electrical potential across the film. Water then moves slowly through the channels by capillary action, helping maintain the ion imbalance and sustain the electrical output for an extended period. A single device measures just 5 by 7 millimeters, with an active film only 15 micrometers thick. With a single 3 µL dose of water, it maintained voltage for more than 20 hours and continued producing an output for up to approximately 45 hours. The thin, flexible films can also be stacked to increase output. In one demonstration, the researchers connected 48 two-layer units in series to directly power a digital clock. The generator worked with tap water, seawater, and sweat, and remained stable across relative humidity levels from 17% to 90% and airflow rates from 5 to 20 L min⁻¹. “Most hydrovoltaic systems rely on evaporation or moisture in the surrounding air, but our device creates the necessary ion difference within the film itself,” said Professor Ko. “This allows it to maintain electrical output even when sealed. Its thin, flexible structure also makes it possible to stack multiple devices, which could support future applications in wearable electronics, compact sensors, and distributed devices.” The study was published online in Advanced Materials on August 12, 2026. Sangyun Na and Geonyoung Jung of UNIST contributed equally as first authors. The research was supported by the National Research Foundation of Korea (NRF), the National Research Council of Science & Technology (NST), and the InnoCORE Program of the Ministry of Science and ICT (MSIT) and Gwangju Institute of Science and Technology (GIST). Journal Reference Sangyun Na, Geonyoung Jung, Yoojin Chang, et al. , “Confinement-Induced Donnan Potential Enables Sealed Hydrovoltaic Power From Microliter Water,” Adv. Mater., (2026).

Research 2026년 09월 28일 월요일

New Study Finds Crystal Surface Directs How Platinum Catalysts Reshape During Reactions

Platinum (Pt) nanoparticles can change shape while catalyzing a reaction, and the surface beneath them helps determine how that transformation unfolds. A research team, led by Professor Kwangjin An of the School of Energy and Chemical Engineering at UNIST, together with Professor Jeong Woo Han's group at Seoul National University, found that different crystal facets of titanium dioxide (TiO₂) produce distinct Pt structures before and during carbon monoxide oxidation. The resulting differences at the Pt–TiO₂ interface have a pronounced effect on catalytic activity. Pt is widely used in catalysts for applications ranging from emissions control to fuel cells. Because the metal is expensive, it is typically dispersed as nanoparticles on a support, whose surface structure can influence both particle shape and reactivity. The researchers examined Pt nanoparticles about 1.8 nanometers across on two facets of anatase TiO₂, known as (001) and (101). Despite their similar size, the particles took on markedly different shapes. On the (001) surface, Pt spread across the TiO₂ to form a relatively flat, hemispherical structure with a broad interface. On the (101) surface, it remained more compact and faceted. The difference persisted as CO oxidation began. Pt on TiO₂(001) extensive retained contact with the support as its surface restructured during the reaction. On TiO₂(101), the particles developed a more ordered, cuboctahedral shape and maintained a more limited interface with the support. The two structures also showed substantially different catalytic behavior. Under the conditions tested, the apparent activation energy for CO oxidation was 58.1 ± 0.3 kJ mol⁻¹ on the predominantly (001)-faceted catalyst, compared with 109.1 ± 1.5 kJ mol⁻¹ on its (101)-dominated counterpart. The difference became more pronounced after the first reaction cycle. Across subsequent reaction cycles, its apparent activation energy fell by 22.7% to 25.6% relative to the first run, while the (101)-based catalyst changed little. The researchers traced this behavior to the interface that developed between Pt and TiO₂ during the reaction. At that interface, oxygen from the TiO₂ lattice participates directly in converting CO to CO₂, leaving oxygen vacuums that must then be replenished. The broader interface formed on TiO₂(001) allows this oxygen cycle to proceed more readily. Calculations likewise found lower energy barriers for oxygen activation on the (001) surface throughout the reaction pathway. To follow these changes, the researchers combined electron microscopy and X-ray spectroscopy with computational modeling. The experiments captured differences in Pt structure before and after reaction, while simulations reproduced the distinct particle shapes favored by the two TiO₂ facets. Density functional theory calculations then connected those structures to differences in reaction energetics. “A catalyst may not be consumed by a reaction, but that does not mean its structure remains unchanged while it is working,” said Professor An. “Our results show that the surface supporting a metal nanoparticle can determine not only its initial structure, but also how that structure evolves during the reaction. Understanding these changes could help guide the design of catalysts that make more effective use of costly metals, such as platinum.” Jihun Kim of UNIST and Yunkyung Kim of Seoul National University contributed equally as first authors. Sinmyung Yoon, Jeong Woo Han, and Kwangjin An served as corresponding authors. The study was published in August 2026 issue of Nature Communications , with support from the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF). Journal Reference Jihun Kim, Yunkyung Kim, Daewon Oh, et al. ,“TiO2-facet-dependent reconstruction of Pt nanoparticles during CO oxidation,” Nat., Commun., (2026).

News 2026년 09월 23일 수요일

UNIST REBOOT Returns with Low-Carbon Action for Chuseok

Students at UNIST brought low-carbon behaviours into their Chuseok celebrations this September, connecting sustainable travel with one of Korea's most important traditional holidays. and traditions into opportunities for everyday climate action. Held on September 22, 2026 UNIST REBOOT 2: The Chuseok Green Bridge Project brought together more than 80 Korean and international students for activities combining sustainable choices with the spirit of the holiday. The event was organized by the Graduate School of Carbon Neutrality in collaboration with the School of Energy and Chemical Engineering. The program builds on the first UNIST REBOOT campaign held in June, when more than 180 students took part in a five-day sustainability challenge and 87 completed all missions to become Net-Zero Masters. While the first campaign focused broadly on changing carbon-intensive habits, REBOOT 2 brought the concept into the Chuseok holiday period. Students were encouraged to document low-carbon choices, including the use of public transportation for holiday travel, and share their Chuseok wishes through an interactive sticker board. Participants also received holiday snack kits, while selected wish-board entries earned gifts intended for students to share with their parents. International students joined the activities alongside their Korean peers, adding a cross-cultural dimension to a program rooted in one of Korea's major holidays. “This second REBOOT project brought our two academic units together and was made possible by the enthusiastic participation of our students,” said Dong Suk Kim, Dean of the Graduate School of Carbon Neutrality. “We will continue to develop campus programs that reflect student ideas while making sustainability both meaningful and engaging.”

News 2026년 09월 11일 금요일

Successful Completion of 2026 UNIST Pioneer Symposium

UNIST brought together leading researchers in batteries, nanoscience, and energy chemistry for the second UNIST Pioneer Symposium, held from September 8 to 9, 2026. Hosted by the School of Energy and Chemical Engineering, the two-day symposium welcomed nearly 400 participants from academia, industry, and research institutions. Building on last year's focus on electrochemistry, the 2026 program broadened its scope to next-generation battery materials and systems, electrocatalysis, energy storage and conversion, and related areas of materials science. Featured speakers included Professor Peidong Yang at the University of California, Berkeley, and Professor Arumugam Manthiram at the University of Texas at Austin, internationally recognized for their work in nanoscience and battery materials, respectively. Professor Manthiram delivered the Nobel Lecture on behalf of John B. Goodenough following his 2029 Nobel Prize in Chemistry. The program also featured researchers working at the forefront of all-solid-state batteries, carbon dioxide conversion, and other areas of materials and energy science. Talks and panel discussions were complemented by poster sessions showcasing research by students and early-career scientists. Industry participation expanded this year, with Sa Heum Kim, Executive Vice President at SK On, who oversees next-generation battery research, joining representatives from major companies. The symposium was also supported by Samsung SDI, the Royal Society of Chemistry (RSC), Wiley, and other academic and research organizations. The Pioneer Symposium was launched in November 2025 with a focus on innovation in electrochemistry. The inaugural meeting featured Stanford University Professor Yi Cui and research spanning battery energy storage, electrocatalysis for hydrogen production, and AI-assisted materials development. This year's program broadened that scope while strengthening exchanges among researchers from academia and industry. Building on UNIST's research in advanced technologies, Ulsan is preparing for new opportunities in future mobility and secondary batteries,” said UNIST President Chong Rae Park. “I hope this symposium will foster meaningful scientific exchange and lead to new ideas and collaborations.”

Research 2026년 09월 08일 화요일

Perovskite Solar Cells Hold Up Under Extreme Temperature Swings

Summary The advent of self-assembled monolayer (SAM)-based hole-selective layers (HSLs) has revolutionized inverted perovskite solar cells (i-PSCs) by enabling record efficiencies, but they are constrained by incomplete surface coverage and interfacial heterogeneity. We devise topology-governed SAMs featuring isomeric linker patterns (LY-ortho [o], LY-meta [m], and LY-para [p]) and uncover the principle that conformational ordering dictates surface coverage and interfacial interaction coupling with perovskite. The topology-optimized LY-m forms a homogeneously dense, stable HSL with superior energy alignment and interfacial passivation. Devices incorporating LY-m achieve a record-high open-circuit voltage of 1.231 V, accompanied by an efficiency of 26.39% (certified 26.37%), while maintaining robust operational stability and scalability. Beyond laboratory metrics, LY-m-based devices withstand −100°C to 100°C thermal cycling with only ∼9% loss, far exceeding the operational limits of state-of-the-art commercial SAMs, while maintaining over 80% of their initial performance at 85°C (T80 ≅ 2,000 h). This work resolves the long-standing role of linker topology and paves the way for extreme-environment-resilient and scalable perovskite photovoltaics. Temperature swings are a major challenge for perovskite solar cells (PSCs), particularly in environments such as space, where materials may repeatedly move between extreme cold and heat. Led by Professors Changduk Yang and Seungjae Shin of the Department of Energy and Chemical Engineering and Professor Myung Hoon Song of the Department of Materials Science and Engineering at UNIST, the team developed perovskite solar cells that withstand such extremes by stabilizing a critical molecular interface. The cells retained about 91% of their initial efficiency after cycling between −100°C and +100°C, with a certified power-conversion efficiency of 26.37%. The key to this advancement is a self-assembled monolayer (SAM), a molecule-thin layer that helps move electrical charges between the electrode and the perovskite absorber. Under severe thermal stress, SAM molecules can shift or cluster, disrupting the interface and degrading performance. The team addressed this problem by changing where the molecular components of the SAM connect. They synthesized three versions with different linker positions and found that LY-m adopted a tilted orientation, allowing its molecules to pack densely and uniformly on the electrode. This arrangement also suppresses the molecular reorganization that can occur under large temperature swings. In thermal-cycling tests, LY-m cells were held alternately at −100°C and +100°C for 30 minutes at each temperature over 16 cycles. They remained operational with only about a 9% loss in efficiency, while cells using a commercial SAM failed under the same conditions. LY-m cells also reached a peak efficiency of 26.39%, with a certified efficiency of 26.37% and an open-circuit voltage of 1.231 V. At 85°C, they maintained more than 80% of their initial performance for approximately 2,000 hours. The approach also performed well at larger scales: a 1 cm² cell achieved 23.25% efficiency, while a 3 × 1 cm² mini-module reached 21.20%. “By changing only the position of the molecular connection, we were able to control how the molecules pack on the electrode,” said Professor Yang. “The resulting interface combines high efficiency with thermal stability, offering a promising route toward perovskite photovoltaics for environments with extreme temperature variations.” The study has been participated by Seunglok Lee and Jeewon Park of the Department of Energy and Chemical Engineering and Jingyu Yang of the Department of Materials Science and Engineering at UNIST, as co-first authors of the study. Published in Joule on August 3, the study has been supported by the Nano & Material Technology Development Program through the National Research Foundation (NRF) of Korea and the InnoCORE program of the Ministry of Science and ICT (MSIT). Journal Reference Seunglok Lee, Jinkyu Yang, Jeewon Park, et al., "Topology-governed self-assembled monolayers enable perovskite solar cells stable at −100°C to +100°C," Joule , (2026).

Research 2026년 09월 01일 화요일

Rethinking What Matters

《Editor's Note: What does it take to make something work better? The answer may be to pare back what is unnecessary, rethink how existing parts are arranged, find another route around a constraint, or widen the frame of the problem itself. This month's UNIST research offers answers in many forms—from leaner AI systems and redesigned material structures to an unexpected route for electron transfer and a broader view of cancer drug resistance. Some of those answers run counter to what we might expect. 》 Less Can Be Enough “How much does AI really need?” AI has spent years scaling up. But recent UNIST research asks a different question—how much can be taken away while keeping what matters? At ACL 2026, researchers introduced GMoE, an architecture that shares experts across layers rather than repeatedly storing similar ones. It cut model parameters by about 63 percent, from 549 million to 204 million, while average accuracy remained virtually unchanged—39.51 percent, compared with 39.55 percent for the baseline. The next target was data. Presented at ICML 2026, CSOR removes redundant training images while preserving meaningful variation within each identity. Using roughly half the original dataset, models retained more than 95 percent of full-data performance in re-identification (ReID) tasks. A third study moved to hardware. An automated design framework for logic-in-memory (LiM) computing optimized the placement and routing of computing elements, cutting computation cycles by 19.6 percent under area constraints. ■ GMoE—Expert Sharing for Smaller AI Models (ACL 2026) ■ CSOR—Less Training Data for ReID AI (ICML 2026 ) ■ LiM—Smarter Chip Design (IEEE TCAD) Arrangement Matters “In materials, where can matter as much as what.” More iron, less corrosion. Iron (Fe) is one of magnesium's most damaging impurities, yet UNIST researchers produced a Mg alloy containing more than six times as much Fe as ultra-high-purity Mg—and it still corroded more slowly. Instead of removing the impurity, the team added scandium (Sc) to form core–shell particles that isolate Fe-rich regions from the surrounding Mg. The corrosion rate fell from 22.2 to 0.38 millimeters per year, nearly a 60-fold reduction. At the molecular scale, thermal annealing changed the packing of an organic semiconductor, more than tripling its absorption dissymmetry and even reversing its preferred handedness of circularly polarized light (CPL). The resulting near-infrared (NIR) photodetector achieved a dissymmetry factor of 0.1 at 850 nanometers. The scale shifts again in perovskite solar cells (PSCs). The same high-efficiency formulation crystallized differently depending on the buried interface beneath it. Tailoring the chloride chemistry to the inverted architecture produced a device with 26.3 percent efficiency and a fill factor (FF) of up to 86.8 percent. ■ Mg Alloy—Shielding Fe to Slow Corrosion (Science Advances) ■ NIR Photodetector—Turning Molecular Packing (Advanced Science) ■ PSCs—Why Architecture Changes Performance (Joule) Another Way Through “How spin opens a new route for electron transfer.” Conventional energetics suggested that electron transfer should be unfavorable. Yet in manganese (Mn)-doped quantum dots (QDs), spin-exchange interactions enabled transfer more than ten times faster than in undoped QDs. The mechanism could help capture energetic hot electrons before their excess energy dissipates—a longstanding challenge in photocatalysis and solar-energy conversion. ■ Hot Electrons—Spin-Enabled Transfer (Nature Communications) Beyond the Tumor “The cells helping cancer resist treatment.” Some of the cells helping breast cancer resist treatment are not part of the tumor at all. UNIST researchers found that nearby fat cells can become cancer-associated adipocytes, which release complement factor D and activate survival signaling in cancer cells. In mouse models, disrupting this TRAP1-driven communication improved the response to chemotherapy, pointing to surrounding adipocytes as potential therapeutic targets alongside the tumor itself. ■ Breast Cancer—How Nearby Fat Cells Drive Drug Resistance (STTT) Explore the latest issue and follow 『The UNIST Brief』 on LinkedIn to stay updated. Subscribe via LinkedIn

News 2026년 08월 31일 월요일

UNIST Brings New Perspectives to Battery Research and Development

More than 300 battery researchers and industry experts gathered at UNIST to examine how artificial intelligence, changing research priorities, and closer ties with industry are shaping battery research and development. Hosted by the School of Energy and Chemical Engineering, the 5th Forum on Recent Trends in Secondary Battery Research and Development brought together participants from universities, companies, and research institutes across Korea. Held from August 27 and 28, this year's program focused on three themes—career development for early-career researchers, the use of AI in battery R&D and manufacturing, and the relationship between academic research and industrial needs. Each session combined presentations with open discussion, allowing participants to compare perspectives across academia and industry. The first session examined how early-career researchers can establish independent research directions and navigate the early stages of an academic career. Haeseong Jang of Chung-Ang University, Minkyung Kim of Kwangwoon University, and Moonseok Chae of Pukyong National University shared their experiences, followed by a discussion led by Mina Lee of POSTECH. The AI-Battery session explored where artificial intelligence can contribute to battery development and manufacturing—and what is needed to put those tools into practice. Inchul Park of DGIST and KyuJung Jun of Korea University presented approaches to AI-enabled battery research, while a discussion led by Dong-Hwa Seo of KAIST addressed data use, implementation, and remaining technical challenges. The final session turned to the relationship between research and industry. Sang-Min Lee of POSTECH and Kyung-Min Jeong of UNIST drew on their development experience to discuss the priorities facing battery researchers. Professor Won-Jin Kwak of UNIST then led a discussion on how universities, companies, and research institutes—with different research goals and timelines—can work more effectively together. The exchange extended beyond the sessions. Sponsors, Ulsan Technopark, and regional companies presented their technologies at exhibition booths, and participants visited Ulsan Technopark on August 28 to see electrode and cell manufacturing, diagnostics, and recycling facilities at an industrial scale. “Battery research increasingly brings together materials innovation, artificial intelligence, and the needs of industry,” said Professor Kwak, who organized the forum. “We hope this meeting will provide a starting point for new research collaborations by connecting early-career researchers with colleagues across academia and industry.” Launched at UNIST in 2022, the forum has since rotated among UNIST, POSTECH, and DGIST. Last year's meeting focused on cathode and anode materials, next-generation batteries, and recycling. This year's program broadened that scope to consider not only battery technologies themselves, but also the researchers, digital tools, and partnerships behind their development.

Research 2026년 08월 28일 금요일

New X-Ray Mapping Technique Enables Non-Destructive Analysis of Large-Area Perovskite Solar Cells

Abstract Scaling perovskite solar cells (PSCs) into large-area modules requires precise control of structural uniformity and mechanical integrity. However, scalable deposition often introduces mesoscale heterogeneities, including grain-orientation disorder and lattice-strain gradients, which limit efficiency and stability. Here, we report an intact-film orthogonal two-dimensional X-ray diffraction mapping (2DXDM) technique that enables full-field, quantitative crystallographic analysis of large-area perovskite films without physical sectioning. The method resolves spatial variations in crystallinity, orientation coherence, and lattice strain across complete modules and is validated against conventional sectioned analyzes such as grazing-incidence wide-angle X-ray diffraction (GI-WAXD) and X-ray diffraction (XRD). Using this approach, we compare static spin-coating (SSC) and dynamic spin-casting (DSC). DSC yields more homogeneous films with relaxed lattice stress and controlled solvate evolution, thereby reducing edge defects. As a result, DSC-based modules achieve 23.0% efficiency (22.7% certified) over 86.4 cm2 and retain over 80% of their initial efficiency after 1,000 h of operation. Perovskite solar cells (PSCs) have reached impressive efficiencies at laboratory scale, but maintaining that performance in larger modules remains challenging. As the films grow larger, differences in crystal orientation and internal strain can develop across the surface, creating defects that reduce efficiency and long-term stability. A research team led by Professors Dong-Seok Kim and Jin Young Kim of the School of Energy and Chemical Engineering and Professor Tae Joo Shin of the Graduate School of Semiconductor Materials and Devices Engineering at UNIST, together with Dr. Yun Seop Shin of the Korea Research Institute of Chemical Technology (KRICT), has developed an X-ray technique that maps these structural variations across an intact perovskite film. Called two-dimensional X-ray diffraction mapping (2DXDM), the technique shows how crystallinity, crystal orientation, and residual strain vary across an entity film without damaging it. Conventional methods often examine selected regions, provide averaged measurements, or require samples to be cut into sections. PSCs are made by depositing a liquid precursor onto a surface, where it dries and crystallizes into a light-absorbing layer. Across a large area, differences in drying and crystallization can leave the center and edges with different structural properties. The researchers used 2DXDM to compare two methods for forming large-area films. In static spin-coating (SSC), the precursor solution is applied before the substrate is spun, while dynamic spin-casting (DSC) deposits the solution drop by drop as the substrate rotates. The resulting maps showed that DSC produced more homogeneous films, with more consistent crystal orientation and lower residual strain. Additional X-ray measurements linked this improvement to better control over colon drying and crystal formation, which helped reduce structural defects near the edges. The more uniform films also delivered strong performance at module scale. DSC-based modules reached a power conversion efficiency of 23.0% over an active area of 86.4 cm², with a certified efficiency of 22.7%. Encapsulated modules retained more than 80% of their initial efficiency after 1,000 hours under continuous illumination. “Conventional methods make it difficult to see how structure varies across an entire film, and cutting a sample for analysis can alter the strain already present” said Professor Shin. “With 2DXDM, we can examine the full area without damaging the film and identify where structural differences occur.” Professor Dong-Seok Kim added, “For large-area perovskite films, what matters is structural uniformity across the entire surface, not just at a few individual points. By showing how fabrication conditions affect that uniformity, this approach can help guide the development of more efficient large-area modules.” Dong Shin Kim of the Graduate School of Semiconductor Materials and Devices Engineering and Jae Hwi Lee of the School of Energy and Chemical Engineering at UNIST, served as first authors. The research used the UNIST-PAL 6D beamline at the Pohang Accelerator Laboratory. The findings were published online in Joule on July 23, 2026. The research was supported by the Ministry of Science and ICT (MSIT), Ministry of Education (ME), National Research Foundation of Korea (NRF), Ministry of Trade, Industry and Energy (MOTIE), Korea Institute of Energy Technology Evaluation and Planning (KETEP), Korea Institute for Advancement of Technology (KIAT), and Korea Research Institute of Chemical Technology (KRICT). Journal Reference Dongshin Kim, Jaehwi Lee, Dongmin Lee, et al ., “Intact-film orthogonal 2D X-ray diffraction mapping for crystallographic homogeneity evaluation in perovskite solar modules,” Joule , (2026).

Research 2026년 08월 19일 수요일

Study Reveals Why Perovskite Performance Changes Across Solar Cell Designs

Abstract A perovskite precursor solution that delivers power conversion efficiencies (PCEs) exceeding 26% in conventional nip solar cells exhibits severe performance losses when directly applied to inverted pin architectures, revealing that high-efficiency compositions are not inherently transferable. Here, we identify a buried-interface crystallization mismatch, arising from the distinct physicochemical natures of inorganic SnO2 electron-transporting layers and organic self-assembled hole-transporting monolayers (SA-HTLs), as the origin of this divergence. The methylammonium chloride (MACl)-associated intermediate phase, MA2Pb3I8·2DMSO, persists and decomposes with strong underlayer dependence, stabilizing beneficially on SnO2 but impeding crystallization on SA-HTLs. To overcome this limitation, we develop a chloride-origin engineering strategy that decouples chloride functionality from volatile organic ammonium species by incorporating low-solubility lead chloride (PbCl2) with strong Pb–Cl coordination. This enables controlled interfacial desolvation and nucleation on SA-HTLs, suppresses buried defects, and establishes buried-interface crystallization control as a design principle for architecture-convergent, high-efficiency perovskite solar cells. Building a high-performance solar cell takes more than getting the materials right. The same ingredients can produce very different results when the layers are arranged differently—and researchers at UNIST have discovered why. Led by Distinguished Professor Sang Il Seok of the School of Energy and Chemical Engineering at UNIST, the team found that the surface beneath the light-absorbing perovskite layer can determine how well its crystals form. By tailoring the material chemistry to that surface, the researchers developed an inverted perovskite solar cell with a power conversion efficiency of 26.3% and improved stability. PSCs can be built in conventional nip or inverted pin configurations. Both have reached high efficiencies, but formulations optimized for one do not necessarily perform as well in the other. Inverted cells are particularly important for perovskite–silicon tandem solar cells, where they are commonly used as the top cell. The researchers found that this performance gap originates at the buried interface, where the perovskite layer forms on the material beneath it. A formulation that achieved efficiencies above 26% in conventional cells lost much of its performance when transferred directly to an inverted design. The difference came down in part to methylammonium chloride (MACl), an additive used to improve perovskite crystal growth. In conventional cells, an intermediate formed by MACl supports crystallization on the underlying inorganic layer. But on the organic layer used in inverted cells, the intermediate persists longer, disrupting crystal growth and leaving behind voids and defects that can lead to electrical losses. Rather than removing chloride, the team changed how it was introduced. The researchers reduced the amount of MACl and added a small amount of lead chloride (PbCl2), whose stronger interaction with chloride helped control where and when crystals began to form. This produced a cleaner buried interface with fewer defects. With the revised formulation, the inverted cells reached a peak efficiency of 26.3% and a fill factor of up to 86.8%, while also showing improved stability. The results demonstrate that controlling how perovskite crystals form at the underlying surface can help high-performance materials work across different solar-cell designs. “High-efficiency formulations developed for conventional PSCs do not necessarily behave the same way in inverted devices,” said Professor Seok. “By identifying the origin of this performance loss, we established a way to control crystal formation at the buried interface. The findings provide a design direction for developing efficient inverted cells for high-performance perovskite–silicon tandem solar cells.” Their findings have been published online in Joule on July 28, 2026. The study was supported by the National Research Foundation of Korea (NRF). Journal Reference Jongbeom Kim, Nahye Shin, Chaehoon Jeon, et al ., “Buried-interface crystallization limits the transferability of high-efficiency perovskite precursor compositions,” Joule ,(2026).

News 2026년 08월 06일 목요일

UNIST to Host ACS Publications Forum on the Future of Nanoscience

UNIST brought together leading scientific journal editors and early-career researchers on July 31 for the ACS Publications Forum: The Future of Nanoscience , a daylong program focused on emerging research across nanoscience and materials science. Co-hosted by ACS Publications and the UNIST School of Energy and Chemical Engineering, the forum was held under the theme ' ACS Editors' Forum with Early-Career Leaders in South Korea .' The program combined editor sessions, research presentations, panel discussions, and a poster session, creating opportunities for researchers at different career stages to exchange ideas and explore new connections. The forum featured Editor-in-Chief Teri W. Odom of Nano Letters, Editor-in-Chief Xiaodong Chen of ACS Nano, and Editor-in-Chief Suzie Pun of ACS Nano Medicine. Editors from Chemistry of Materials, ACS Nano, and Nano Letters, as well as representatives from ACS Publications, also participated. The afternoon Emerging Scholar Program highlighted research by early-career scientists from UNIST and other universities in Korea. Presentations covered battery chemistry and materials, energy conversion, catalysis, polymer self-assembly, stretchable electronics, optoelectronics, AI sensors, and two-dimensional materials, reflecting the breadth of current research across energy materials, soft matter, and electronics. The program also included a poster session featuring student research. A panel discussion with journal editors provided another opportunity to exchange perspectives on scientific publishing and emerging directions in nanoscience, while networking sessions connected editors, faculty members, and early-career researchers. Organized by Professor Hyun-Wook Lee of the School of Energy and Chemical Engineering at UNIST, the forum was designed to connect established journal editors with emerging researchers and strengthen scientific exchange across the nanoscience community. The event's broader research scope ranged from battery chemistry and energy conversion to stretchable electronics and polymer self-assembly.

Research 2026년 08월 01일 토요일

Beyond the Obvious

《Editor's Note: The biggest scientific advances do not always come from discovering something new. Sometimes, they begin by seeing familiar problems in a new light. This month's stories invite us to look beyond the obvious. Across artificial intelligence, semiconductor materials, nanotechnology, and biomedical science, UNIST researchers examined assumptions, structures, and interactions that can easily go unnoticed—but often determine how a system behaves. Their findings show how a deeper understanding of what is already there can open new directions for discovery.》 Questioning Assumptions “The first answer is not always the right one.” Scientific discovery often begins by asking whether the original question was complete. Several AI studies featured this month did just that, revisiting assumptions about how machines learn, forget, reason, and communicate. In federated learning, researchers found that differences in camera viewpoints—not only privacy constraints or data distribution—can significantly affect how well AI models learn together. Another team showed that machine unlearning involves more than simply removing data: forgetting can unintentionally alter knowledge that should remain. Elsewhere, a new communication framework showed that effective cooperation among AI agents depends less on exchanging more information than on exchanging the right information. Other studies reconsidered how AI systems reason across multiple views of the same scene and explored how quantum computing could reduce the cost of training robust AI models. Different problems, but a common starting point: questioning the assumptions built into them. Together, these studies point to a simple lesson: better answers often begin with better questions. ■ Rethinking Federated Learning: Camera Viewpoints Matter (CVPR 2026) ■ Making AI Forget—Without Losing What Matters (ICML 2026 ) ■ Smarter Communication for Collaborative AI (ICML 2026) ■ Rethinking Multiview Reasoning (ICML 2026) ■ Quantum Algorithm Cuts the Cost of Training Robust AI (ICML 2026) Looking Beneath the Surface “The smallest details often hold the biggest clues.” Across materials science, biology, nanotechnology, and semiconductor engineering, UNIST researchers examined structures and interactions that are easy to miss but can have an outsized influence on how materials, devices, and biological systems behave. In semiconductor research, the spacing between neighboring atoms emerged as a critical factor in controlling material properties and device performance. At the nanoscale, researchers examined how the surface chemistry of quantum dots influences their behavior in imaging. Another study turned to microscopic wrinkles, showing how their geometry can reshape optical properties. The same attention to underlying mechanisms extended to biology, where researchers found that familiar forms of cell death do not always follow the pathways scientists expect. Together, these studies show how seemingly minor details—from atomic spacing and surface chemistry to microscopic geometry and cellular mechanisms—can fundamentally change our understanding of a system. Sometimes, the most consequential discoveries begin with something that was there all along, waiting to be examined more closely. ■ Atomic Precision for Better Semiconductors (Chem. Mater., 2026) ■ A New Perspective on QD Imaging (Nano Converg., 2026) ■ Wrinkles that Reshape Photonics (Adv. Funct. Mater., 2026) ■ When Cell Death Follows Different Rules (Cell Death Differ., 2026) Across very different fields, these studies share a common instinct: question the assumption, examine the detail, and look again. What appears familiar can still hold unanswered questions. Looking beyond the obvious is not simply how these discoveries were made. It is how scientific discovery moves forward. Explore the latest issue and follow 『The UNIST Brief』 on LinkedIn to stay updated. Subscribe via LinkedIn