Samsung Advanced Institute of Technology

Polycrystalline ion conductors are widely used as solid electrolytes in energy storage technologies. However, they often exhibit poor ion transport across grain boundaries and pores. This work demonstrates that strategically tuning the mesoscale microstructures, including pore size, pore distribution, and chemical compositions of grain boundaries, can improve ion transport. Using LiTa 2 PO 8 as a case study, we have shown that the combination of LiF as a sintering agent with Hf ⁴⁺ implantation improves grain-grain contact, resulting in smaller, evenly distributed pores, reduced chemical contrast, and minimized nonconductive impurities. A suite of techniques has been used to decouple the effects of LiF and Hf ⁴⁺ . Specifically, LiF modifies particle shape and breaks large pores into smaller ones, while Hf ⁴⁺ addresses the chemical mismatches between grains and grain boundaries. Consequently, this approach achieves nearly two orders of magnitude improvement in ion conduction. Tuning mesoscale structures offers a cost-effective method for enhancing ion transport in polycrystalline systems and has notable implications for synthesizing high-performance ionic materials.

Magnetic domain walls (DWs) often exhibit creep motion, a form of collective dynamics observed in weak magnetic fields. In this study, we investigate the correlation between magnetic DW creep behavior and fundamental magnetic properties through analytical analysis and experimental demonstration. Specifically, we examined DW creep motion in a series of Pt/Co/X heterostructures, where X represents various non-magnetic layers (Ta, Ti, Ru, and Au) that are critical for inducing magnetic chirality. By systematically varying the Co layer thickness for each material X, we uncover a universal correlation between the creep scaling constant and magnetic parameters, independent of both the Co layer thickness and the choice of material X. These findings underscore the dominant role of the Pt/Co interface, rather than the Co/X interface, in governing DW creep behavior, enabling the independent tuning of both creep parameters and magnetic chirality. The present results provide clear and practical guidelines for engineering spintronic devices, facilitating advances in device performance and design.

In synthesis planning, identifying and optimizing chemical reactions are important for the successful design of synthetic pathways to target substances. Chemical reaction databases assist chemists in gaining insights into this process. Traditionally, searching for relevant records from a reaction database has relied on the manual formulation of queries by chemists based on their search purposes, which is challenging without explicit knowledge of what they are searching for. In this study, we propose an intelligent chemical reaction search system that simplifies the process of enhancing the search results. When a user submits a query, a list of relevant records is retrieved from the reaction database. Users can express their preferences and requirements by providing binary ratings for the individual retrieved records. The search results are refined based on the user feedback. To implement this system effectively, we incorporate and adapt contrastive representation learning, dimensionality reduction, and human-in-the-loop techniques. Contrastive learning is used to train a representation model that embeds records in the reaction database as numerical vectors suitable for chemical reaction searches. Dimensionality reduction is applied to compress these vectors, thereby enhancing the search efficiency. Human-in-the-loop is integrated to iteratively update the representation model by reflecting user feedback. Through experimental investigations, we demonstrate that the proposed method effectively improves the chemical reaction search towards better alignment with user preferences and requirements. Scientific contribution This study seeks to enhance the search functionality of chemical reaction databases by drawing inspiration from recommender systems. The proposed method simplifies the search process, offering an alternative to the complexity of formulating explicit query rules. We believe that the proposed method can assist users in efficiently discovering records relevant to target reactions, especially when they encounter difficulties in crafting detailed queries due to limited knowledge.

Oxide ceramic electrolytes for realization of high-energy lithium metal batteries typically require high-temperature processes to achieve the desired phase formation and inter-particle sintering. However, such high-temperature processing can lead to compositional changes or mechanical deformation, compromising material reliability. Here, we introduce a disorder-driven, sintering-free approach to synthesize garnet-type solid electrolyte via the creation of an amorphous matrix followed by a single-step mild heat-treatment. The softened mechanical property (yield pressure, Py = 359.8 MPa) of disordered base materials enables the facile formation of a dense amorphous matrix and the preserving of inter-particle connectivity during crystallization. The formation of the cubic-phase garnet is triggered at a lowered temperature of 350 °C, achieving a Li⁺ ionic conductivity of 1.8 × 10–4 S/cm at 25 °C through a single-step mild heat treatment at 500 °C. The disorder-driven garnet solid electrolyte exhibits electrochemical performance comparable to conventional garnet solid electrolyte sintered at >1100 °C. These findings will promote the fabrication of uniform, thin, and wide solid electrolyte membranes, which is a significant hurdle in the commercialization of oxide-based lithium metal batteries, and demonstrate the untapped capabilities of garnet-type oxide solid electrolytes.

Nanosecond pulse dielectric barrier discharge (NPDBD) exhibits high energy efficiency, making it a promising approach for volatile organic compound (VOC) decomposition. However, accurately measuring the energy delivered to the plasma in nanosecond pulse systems is difficult due to the influence of parasitic components inherent in the system's electrical characteristics. This study develops and validates methods for measuring the delivered energy in NPDBD, ensuring accurate energy efficiency measurements. Precise discharge current measurement methods are proposed by comparing experimental and simulation results. Toluene decomposition experiments, conducted under varying applied voltage and pulse width conditions, reveal an energy efficiency range of 35–55 g/kWh. The validated energy measurement methods provide a foundation for the removal of VOCs in NPDBD systems, leading to more efficient electrical conditions for industrial applications.

This study investigates the hole and electron conduction properties of thin-film transistors (TFTs) with a tin monoxide (SnO) channel and indium tin oxide (ITO) source/drain (S/D) electrodes, considering the adoption to three-dimensional (3D) NAND Flash. Compared to SnO TFTs with gold (Au) S/D electrodes, significant enhancement of electron conduction was observed when adopting ITO S/D electrodes. The ITO electrodes decreased the Schottky barrier height for electron injection, enhancing electron conduction and consequently inducing ambipolar conduction behavior. The ambipolar SnO TFT exhibited coexisting electron and hole channels, which induced a transition from normal to abnormal conduction properties. These transitioning conduction characteristics were analyzed, and a method to extract saturation mobility in ambipolar TFTs considering the electron–hole (e–h) recombination effect was proposed. Furthermore, bias-stress stability tests were conducted to examine the effect of the coexisting electron and hole channels on the carrier-trapping properties. This analysis provides valuable insights into the electrical characteristics of ambipolar TFTs, considering the coexisting electron and hole channels.

Area‐selective atomic layer deposition (AS‐ALD) has focused on controlling the promotion or blocking of precursor molecules on “heterogeneous” surfaces comprising different materials. This study proposes a new concept of AS‐ALD on “homogeneous” surfaces comprising a single material. In this work, a homogeneous ZrO2 substrate is selectively fluorinated using sulfur hexafluoride (SF6) gas. The SF6 decomposes and incorporates into oxygen vacancies in ZrO2, forming F‐terminated surface at grain boundaries (GBs). In the following step, the remaining hydroxyl‐terminated ZrO2 areas are blocked by a cyclopentadienyl ligand to prevent aluminum precursor adsorption. Density functional theory and Monte Carlo simulations show that selectively passivated GBs of ZrO2 lead to the selective adsorption of ZrCp(NMe2)3 inhibitors. Selective growth of Al2O3 along GBs of ZrO2 is observed by elemental mapping from transmission electron microscopy. Finally, GB‐selective Al2O3 increases overalldielectric constant by 15.5% in ZrO2/Al2O3/ZrO2 stacks with no increase in leakage currents, showing that the GB‐selective Al2O3 incorporation suffices to passivate leakage paths through ZrO2 GBs. These findings provide fundamental guidelines for performing AS‐ALD on homogeneous surfaces and highlight the potential of this approach for applications in next‐generation electronic devices.

Objectives This study aimed to explore communication challenges between parents and healthcare providers in paediatric emergency departments (EDs) and to define the roles and functions of an artificial intelligence (AI)-assisted communication agent that could bridge existing gaps. Design A qualitative study using in-depth interviews and affinity diagram methodology to analyse interview data. Setting A tertiary paediatric ED in South Korea. Participants 11 parents of paediatric patients and 11 ED staff members (physicians, nurses and security personnel). Primary and secondary outcome measures The study examined parent–provider communication difficulties, emotional responses and situational factors contributing to miscommunication and increased workload for ED staff. Results The study identified key emotional factors—fear, anger and sadness—that negatively affect communication between parents and ED staff. Parents experienced frustration due to uncertainty, insufficient information and difficulty navigating the ED process. ED staff faced challenges in managing anxious or demanding parents, resulting in increased workload and communication breakdowns. Conclusions An AI-assisted communication agent could help mitigate these challenges by providing timely information, managing non-medical inquiries and supporting both parents and ED staff at critical stages of the ED visit. Implementing such technology has the potential to improve communication and enhance overall patient care in paediatric emergency settings.

Background: Immunocompromised (IC) pediatric patients are at increased risk of severe acute respiratory syndrome coronavirus 2 infection, but the viral kinetics and sero-immunologic response in pediatric IC patients are not fully understood. Methods: From April to June 2022, a prospective cohort study was conducted. IC pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) were enrolled. Serial saliva swab and serum specimens were subjected to reverse transcription polymerase chain reaction assays with mutation sequencing, viral culture, anti-spike-protein, anti-nucleocapsid antibody assays, plaque reduction neutralization test (PRNT) and multiplex cytokine assays. Results: Eleven IC children were evaluated. Their COVID-19 symptoms resolved promptly (median, 2.5 days; interquartile range, 2.0-4.3). Saliva swab specimens contained lower viral loads than nasopharyngeal swabs (P = 0.008). All cases were BA.2 infection, and 45.5% tested negative within 14 days by saliva swab from symptom onset. Eight (72.7%) showed a time-dependent increase in BA.2 PRNT titers, followed by rapid waning. Multiplex cytokine assays revealed that monocyte/macrophage activation and Th₁ responses were comparable to those of non-IC adults. Activation of interleukin (IL)-1Ra and IL-6 was brief, and IL-17A was suppressed. Activated interferon (IFN)-γ and IL-18/IL-1F4 signals were observed. Conclusion: IC pediatric patients rapidly recovered from COVID-19 with low viral loads. Antibody response was limited, but cytokine analysis suggested an enhanced IFN-γ- and IL-18-mediated immune response without excessive activation of inflammatory cascades. To validate our observation, immune cell-based functional studies need to be conducted among IC and non-IC children.

A molecular design strategy for managing the emission energy and energy levels while enhancing the emission efficiency of monoatomic multiresonance (MR) emitters based on a fused indolocarbazole (ICz) chromophore is developed by introducing a cyano (CN) unit as an MR manager. The MR manager intensifies the short‐range charge transfer character of the fused ICz‐based blue emitter, resulting in pure‐blue emission with a narrow emission spectrum and an enhanced photoluminescence quantum yield. As a result, the CN MR manager‐modified ICz derivative demonstrates a high external quantum efficiency (EQE) of 23.1%, a small full width at half maximum of 22 nm, and a pure‐blue color coordinate of (0.142, 0.061). In addition, the introduction of the MR manager enables the fabrication of a blue phosphor‐sensitized fluorescence device with an EQE of 24.6% while maintaining the narrow emission spectrum.

The stacking sequence of two-dimensional hexagonal boron nitride (hBN) is a critical factor that determines its polytypes and its distinct physical properties. Although most hBN layers adopt the thermodynamically stable AA′ stacking sequence, achieving alternative stacking configurations has remained a long-standing challenge. Here we demonstrate the scalable synthesis of hBN featuring unprecedented AA stacking, where atomic monolayers align along the c axis without any translation or rotation. This previously considered thermodynamically unfavourable hBN polytype is achieved through epitaxial growth on a two-inch single-crystalline gallium nitride wafer, using a metal–organic chemical vapour deposition technique. Comprehensive structural and optical characterizations, complemented by theoretical modelling, evidence the formation of AA-stacked multilayer hBN and reveal that hBN nucleation on the vicinal gallium nitride surface drives the unidirectional alignment of layers. Here electron doping plays a central role in stabilizing the AA stacking configuration. Our findings provide further insights into the scalable synthesis of engineered hBN polytypes, characterized by unique properties such as large optical nonlinearity.

In this work, a new n-type small molecule consisting of a fused thiophene backbone and barbituric acid as the electron withdrawing groups is reported. For green-selective organic photodiodes, when combined...

This study aimed to assess the efficacy and safety of combining cemiplimab, an anti-PD1 antibody, with isatuximab, an anti-CD38 antibody, in relapsed or refractory extranodal NK/T-cell lymphoma (R/R ENKTL). The hypothesis was that CD38 blockade could enhance the antitumor activity of PD1 inhibitors. Eligible patients received cemiplimab (250 mg on days 1 and 15) and isatuximab (10 mg/kg on days 2 and 16) intravenously every four weeks for six cycles. Responders then received cemiplimab (350 mg) and isatuximab (10 mg/kg) every three weeks for up to 24 months. The primary endpoint was the complete response (CR) rate based on the best response. Out of 37 patients enrolled, the CR rate was 51% (19/37), exceeding the primary endpoint of 40%, and the objective response rate was 65% (24/37). After a median follow-up of 30.2 months (95% CI: 25.6-34.8 months), the median progression-free survival was 9.5 months (95% CI: 1.4-17.6 months), while the median overall survival had not yet been reached. Patients achieving CR received a median of 28 cycles (range: 4-33), and the median duration of response for responders (n = 24) was 29.4 months (95% CI: 15.4-43.4 months). Structural variations disrupting the 3'-UTR of PD-L1 and high PD-L1 expression were observed in responders. Most adverse events were mild (grade 1-2), with grade ≥3 events (32%) and no treatment-related deaths. The combination of isatuximab and cemiplimab demonstrated sustained antitumor activity and a manageable safety profile in R/R ENKTL. This phase II trial is registered at www.clinicaltrials.gov as #NCT04763616.

Background This study aimed to comprehensively characterize the gut microbiome and identify individual and grouped gut microbes associated with food allergy (FA) using 16S rRNA gene sequencing. Methods Fecal samples were collected from children with IgE‐mediated FA and from sex‐ and age‐matched controls. The V3–V4 variable regions of the 16S rRNA gene of the gut microbiome were profiled using next‐generation sequencing (Illumina, USA). Bacterial species richness, intracommunity diversity, and intergroup dissimilarity were evaluated. Functional profiles were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) and the Minimal Set of Pathways (MinPath) algorithm. Results Fecal samples were collected from children with IgE‐mediated FA (n = 66) and from sex‐ and age‐matched controls (n = 22). Gut microbiome richness (p < 0.0001), intra‐community diversity (p < 0.0001), and inter‐community diversity (p = 0.0004) were higher in the healthy group than in the FA group. Patients with FA were enriched in Blautia, Fusicatenibacter, and Ruminococcus_g5 compared with healthy control individuals (all p < 0.05). Healthy control individuals were significantly enriched in Oscillibacter and Ruminococcus compared with patients with FA (all p < 0.05). Functional pathway analysis identified enrichment in pathways related to endoglucanase in healthy controls and the ATP‐binding cassette (ABC) transport system in FA patients. Conclusions The gut microbiomes of patients with FA and healthy control individuals had different taxonomic abundances, and the microbiome richness and diversity of the bacterial flora of patients with FA were reduced compared with controls.

Advances in semiconductor technology have been primarily driven by exponentially reducing the size of silicon transistors and pushing the quantum limit. However, continued scaling becomes extremely difficult in accordance with Moore's law. Conversely, recent advances in monolithic and heterogeneous integration by exploring non‐group IV materials envision beyond CMOS scaling. This study entails the development of scalable van der Waals (vdW) integration technology by using all CMOS back‐end‐of‐line‐compatible processes: vertical 3D and lateral 2D integration of III‐N devices, 2D materials (graphene and molybdenum disulfide), and CMOS. Advanced fluidic‐assisted self‐alignment transfer (FAST) provides a process accuracy of ≈ 32.6 nm as analyzed on a 200 mm wafer scale. The freestanding III‐N chips are vdW integrated onto 2D materials, and the vdW interfaced multi‐layer graphene successfully functioned as a back‐gating interconnect line. Moreover, fidelity of the vdW interface is confirmed by conducting systematic yield, uniformity, and reliability analysis. The unique fourfold rotationally symmetric design of GaN transistors makes them compatible with massive and random FAST processing. GaN‐based radio‐frequency power and cascode GaN/Si transistors are integrated on silicon‐on‐insulator‐CMOS. The proposed approach affords a remarkable advantage by surpassing the physical limits and facilitating functional diversification, thus advancing the concept of “More than Moore.”