The rapid proliferation of artificial intelligence (AI) servers and high-performance computing systems has significantly elevated the technical and reliability requirements for multilayer ceramic capacitors (MLCCs). In such systems, MLCCs are critical passive components that must deliver high capacitance, fast transient response, and robust insulation performance under high temperature, voltage, and current density. This review examines the material, structural, and process innovations that underpin MLCC performance in AI applications. Key topics include the development of ultrathin dielectric layers (<0.5 μm), rare-earth doped BaTiO₃-based dielectrics with enhanced DC bias stability, and core-shell microstructures designed for temperature and field resilience. The paper also explores insulation degradation mechanisms―such as vacancydriven conduction and demixing―and advanced reliability assessment methodologies, including HALT, TSDC, and the tipping point framework. Comparisons with automotive-grade MLCCs highlight the unique requirements of AI systems, such as ultraminiaturization, high volumetric efficiency, and ppm-level field failure rates. Finally, the review discusses emerging trends in MLCC technology, including particle engineering, interface stabilization, and advanced lamination techniques, and provides insight into the future direction of capacitor development tailored to AI data center environments.

Citations

• Reliability enhancement in Dy-doped BaTiO3 nanoceramics: from core–shell structure to phase-field modeling
  Shuyan Huang, Xinjie Wang, Mengjian Xiao, Xu Cheng, Xiaohui Wang
  Journal of Materials Science.2026; 61(37): 27665.     CrossRef
• Key factors determining high-temperature operating lifetime of multilayer ceramic capacitors (MLCCs)
  Yuto Tomura, Tzu-han Weng, Yusuke Oba, Tomohiro Kajita, Daiki Ishii
  Japanese Journal of Applied Physics.2026; 65(16): 16SP05.     CrossRef
• Effect of BaZrO3 Addition on the Frequency and Temperature Dependent Dielectric Properties of BaTiO3-Based Ceramics
  Won-Su Lee, Jong Kyu Lee, Moon-Taek Cho, Jung Rag Yoon
  Journal of Electrical and Electronic Materials.2026; 39(5): 478.     CrossRef
• Manufacturing Process Optimization of Oxide-Based Multilayer Ceramic Batteries Using Multilayer Ceramic Processing Technologies
  Won-Su Lee, Jong Kyu Lee, Jung Rag Yoon
  Journal of Electrical and Electronic Materials.2026; 39(5): 519.     CrossRef
• Particle Size-Controlled and Characteristics of Hydrothermally Synthesized BaTiO3 Nanoparticles
  Youngseo Song, Chang Kyu Jeong
  Ceramist.2026; 29(3): 444.     CrossRef
• Architecture-dependent microstructural and dielectric evolution of BaTiO3-based dielectrics from bulk ceramics to multilayer ceramic capacitors
  Huizhan He, Saiwei Luan, Junhui Tan, Zhangping Wu, Lei Zhang
  Journal of Materials Science: Materials in Electronics.2026;[Epub]     CrossRef

As technologies such as artificial intelligence, autonomous driving, the Internet of Things, wearable electronics, and edge computing continue to spread in the era of the Fourth Industrial Revolution, the importance of hardware security for the safe storage, transmission, and processing of large volumes of data has grown substantially. One of the key components of such security systems is the true random number generator (TRNG), which produces unpredictable random numbers for cryptographic use. In recent years, research on TRNGs has increasingly moved beyond conventional CMOS-based approaches toward semiconductor devices built from emerging materials. These material-based TRNGs offer several advantages, including high integration density, low power consumption, compact form factors, and strong suitability for next-generation edge and IoT environments, because they can directly exploit the intrinsic stochasticity of the device itself as an entropy source. In this review, recent studies on TRNGs based on emerging material-based semiconductor devices are examined from the perspectives of entropy sources, device structures, randomness validation, and wearable/flexible extensions. By bringing together the key physical mechanisms, device platforms, evaluation criteria, and prospects for wearable and flexible electronics in edge and IoT environments, this review aims to provide a useful framework for future research on hardware security devices.

This review addresses the development trends of dielectric ceramics, the key material for Multilayer Ceramic Capacitors (MLCCs), which are essential components in high-performance electronic devices. Traditional MLCCs have employed BaTiO₃ (BT)-based dielectrics to achieve high dielectric constant and low resistance. By minimizing oxygen vacancies and suppressing grain growth in BT materials, the temperature and voltage stability of MLCCs have been improved, leading to the development of MLCCs with diverse properties. However, the maximum dielectric constant of approximately 3000 in BT materials poses a limitation in overcoming the trade-off between rated voltage and capacitance density. Therefore, ultra-high permittivity dielectric materials have gained attention to meet the requirements of ultra-high-performance MLCCs, and ongoing research focuses on enhancing the temperature and frequency stability of these materials. This review analyzes the characteristics and limitations of conventional BT materials and explores recent research trends and future potential in developing new MLCCs based on ultra-high dielectric constant materials.

Citations

• Particle Size-Controlled and Characteristics of Hydrothermally Synthesized BaTiO3 Nanoparticles
  Youngseo Song, Chang Kyu Jeong
  Ceramist.2026; 29(3): 444.     CrossRef

Lead-free bismuth sodium titanate (BNT)-based ceramics have attracted strong attention as environmentally benign dielectric materials for high-efficiency electrostatic energy-storage capacitors. A key challenge is that pristine BNT typically exhibits large hysteresis, high remnant polarization, and limited dielectric reliability, which restrict recoverable energy storage and efficiency under practical electric fields. Here, we present a focused mini-review of recent studies to clarify how composition design, phase boundary tuning, defect chemistry, and microstructural control collectively enable slim or pinched polarization-electric field (P-E) behavior and improved energy-storage functionality in BNT-related bulk ceramics. The reviewed outcomes consistently show that stabilizing relaxor states governed by polar nanoregions (PNRs), often via solid-solution engineering and secondary relaxor/antiferroelectric-like incorporation, suppresses irreversible switching and reduces hysteresis loss, while densification and grain-size control enhance electrical homogeneity and breakdown strength. In addition, defect-mediated tuning of oxygen vacancy-related complexes is highlighted as an independent lever to control relaxor ergodicity and polarization reversibility, providing a complementary route to slim-loop optimization. These insights are expected to guide integrated design strategies that couple phase/relaxor-state engineering with defect and microstructure optimization, accelerating the development of reliable, temperature-robust, lead-free dielectric capacitors based on BNT-related ceramics.

Citations

• Progress and outlook of dielectric energy storage characteristics of Lead–free (K,Na)NbO3 based bulk ceramics/composite films for capacitors
  Twinkle, Varun Kamboj, Chetna, Arun Kumar Singh, Gurpreet Singh, Sanjeev Kumar
  Current Opinion in Solid State and Materials Science.2026; 44: 101297.     CrossRef
• Structural Stability and Electromechanical Response of Lead-Free (Bi1/2Na1/2)TiO3‒SrTiO3 Ceramics Under A-Site Strontium Non-Stoichiometry
  Yubin Kang, Trang An Duong, Gwang-Hwi Jeong, Chang Won Ahn, Yong-Jai Kwon, Hyoung-Su Han
  Journal of Electrical and Electronic Materials.2026; 39(5): 549.     CrossRef
• Antiferrodistortive Matrix Engineering Reprograms Polarization Pathways for Ultrahigh Energy Storage at Moderate Electric Fields
  Leiyang Zhang, Hongchen Wang, Linpeng Tang, Yuxuan Yang, Ruiyi Jing, Yang Li, Yunyao Huang, Zizheng Song, Liqiang He, Dong Wang, Tengfei Hu, Zhanbing He, Yang Zhang, Haijun Wu, Li Jin
  Advanced Energy Materials.2026;[Epub]     CrossRef

Two-dimensional van der Waals (2D vdW) magnets have attracted enormous attention as an emerging material platform for magnetism, spintronics, and multifunctional applications. Their single-crystalline layered structures, layer-number controllability, and unique 2D properties provide unique opportunities that are difficult to achieve in conventional magnetic materials. However, the discovery and development of new 2D magnetic compounds require considerable time and effort, and only a limited number of these materials have been reported to be suitable for practical use. Therefore, materials engineering based on already established 2D vdW magnets has become an important research direction to explore new characteristics and find a practical route for device applications. This review summarizes recent materials engineering pathways for 2D vdW magnets. The main contents focus on the engineering strategy through electrostatic, chemical, lattice, symmetry, and heterostructure ways. These approaches provide practical design routes for tailoring magnetic properties beyond intrinsic 2D vdW magnets. Further progress will require broader application to various types of materials and delicate optimization that connects expanding fundamental magnetism with electromagnetic device applications.

In this study, we systematically investigated the effects of thermal atomic layer deposition (ALD) conditions on the electrical characteristics of conductive-filament-based volatile threshold switching memristors with a Pt/Al₂O₃/Ag structure. Although volatile threshold switching memristors have attracted significant attention for neuromorphic computing applications such as spiking neural networks, the impact of dielectric deposition conditions on their switching behavior remains relatively unexplored. The number of ALD cycles was varied from 40 to 200, and the deposition temperature was varied from 50 to 250°C to evaluate their effects on threshold voltage (V_th), off-state resistance (R_off), and device yield. Devices fabricated using 75–150 ALD cycles showed clear volatile threshold switching behavior with relatively high device yield, whereas excessively low or high cycle numbers resulted in short-type and open-type failures, respectively. In addition, V_th and R_off tended to increase at higher deposition temperatures, while the device yield significantly degraded above 150°C. These results indicate that the number of ALD cycles and the deposition temperature define a critical process window for achieving volatile threshold switching while suppressing both short-type and open-type failures. This study provides practical guidelines for optimizing dielectric ALD conditions in conductive-filament-based volatile threshold switching memristors for future neuromorphic hardware applications.

This study investigates the effect of dielectric layer thickness on the electrical and reliability characteristics of BaTiO₃- based X8R multilayer ceramic capacitors (MLCCs) for automotive applications. MLCCs with 30 dielectric layers and thicknesses ranging from 5 to 30 μm were fabricated, and key parameters―including capacitance, equivalent series resistance (ESR), insulation resistance (IR), breakdown voltage (BDV), DC-bias characteristics, temperature coefficient of capacitance (TCC), and ripple current-induced heating―were evaluated. The dielectric constant (~2,000) and sintering shrinkage (~-25%) were nearly independent of thickness, confirming stable microstructure formation. ESR increased with thickness, while normalized BDV (V/μm) decreased due to defect accumulation. IR improved with increasing thickness but dropped sharply above 125℃. Dielectrics thinner than 10 μm exhibited significant capacitance degradation under DC-bias and temperature variation, reflecting strong internal field effects. Ripple-induced heating correlated directly with ESR. These results indicate that, although thinner layers enhance capacitance density, reducing the thickness below 10 μm compromises bias stability and thermal reliability. A minimum dielectric thickness of 10 μm is therefore recommended to achieve an optimal balance between electrical performance and durability in high-reliability X8R MLCCs.

Citations

• Structural Analysis of Electric Field-Induced Polarization and Strain in Ferroelectric BaTiO₃
  Jae Hwan Park
  Journal of Electrical and Electronic Materials.2026; 39(4): 374.     CrossRef

Multilayer ceramic batteries (MLCBs) have attracted increasing attention as compact all-solid-state energy-storage devices that can be manufactured using multilayer ceramic processing technologies. In this study, an MLCC-compatible fabrication process for oxide-based MLCBs was developed using Li₁₊ₓAlₓTi₂₋ₓ(PO₄)₃ (LATP) solid electrolytes, Li₃V₂(PO₄)₃ (LVP) cathodes, and Cu current collectors. Commercial LATP powders were evaluated in terms of particle-size distribution, phase purity, thermal stability, and ionic conductivity. The selected LATP powder was subsequently employed for tape-cast green-sheet fabrication, and the effects of polyvinyl butyral (PVB) binder content on slurry rheology and sheet microstructure were investigated. An optimized binder composition containing 11 wt% PVB (BM-2/BH-3 = 3:7) provided improved processability and microstructural uniformity. Drying conditions during sequential electrode printing were also optimized to suppress sheet warpage and improve multilayer registration. Thermogravimetric and differential thermal analyses (TG–DTA) were used to establish an optimized two-step debinding and co-firing process under a controlled reducing atmosphere. The resulting multilayer structures exhibited uniform densification without significant blistering, delamination, or interfacial defects. Charge–discharge measurements confirmed that electrochemical functionality was retained after the complete manufacturing process, yielding a discharge capacity of approximately 2.5–2.7 μAh.

Metal sacrificial-layer-assisted transfer is a promising strategy for transferring thermally annealed thin films onto flexible polymer substrates without exposing the receiver substrate to thermal damage. However, stable release of the annealed thin-film stack remains challenging because high-temperature annealing can alter the etching behavior of the sacrificial metal layer and the protective oxide layer. In this study, we propose a thin-film transfer process using a Ni metal sacrificial layer and etch access holes, in which an SU-8/Ti/SiO₂ transferable stack was fabricated on a rigid sapphire donor substrate, annealed at 400–700°C, selectively released by Ni etching, and transferred onto a flexible PET receiver substrate. As the annealing temperature increased from 400 to 700°C, the SiO₂ etch rate decreased from 6.8–6.96 to 2.61–3.83 nm/s, while the Ni release time increased from 72–77 to 82–95 min; nevertheless, the transferable stack was successfully transferred under all process conditions with image-based transfer yields of 58.81–82.76%, with the highest yield obtained for the 200 nm Ni sacrificial layer annealed at 550°C. These results demonstrate the process feasibility of the proposed metal sacrificial-layer and etch-access-hole-based transfer approach for transferring thermally annealed thin-film structures from rigid donor substrates to flexible receiver substrates.

The effects of BaZrO₃ addition on the structural and electrical properties of BaTiO₃-based base-metal-electrode (BME) multilayer ceramic capacitor (MLCC) ceramics were investigated. Dielectric compositions containing 0–9 wt% BaZrO₃ were fabricated using a conventional MLCC process, and their crystal structure, dielectric behavior, temperature stability, frequency stability, and insulation resistance were evaluated. X-ray diffraction and Rietveld refinement confirmed the formation of a single-phase perovskite structure for all compositions. Increasing BaZrO₃ content resulted in a systematic shift of diffraction peaks toward lower angles and an increase in unit-cell volume from 64.61 to 66.05 ų, indicating successful Zr incorporation into the BaTiO₃ lattice. The dielectric permittivity increased with BaZrO₃ addition and reached a maximum value of approximately 2,110 at 6 wt%, while dielectric loss decreased significantly. Capacitance stability against temperature and frequency variations was markedly improved with increasing BaZrO₃ content. In addition, insulation resistance increased substantially over the investigated temperature range, demonstrating enhanced electrical reliability.

X-ray photon correlation spectroscopy (XPCS) provides access to nanoscale dynamics, yet practical approaches for interpreting its data remain limited. This tutorial presents a systematic framework for XPCS data analysis, illustrated using measurements performed at the NSLS-II CHX beamline. The fundamental concepts of speckle pattern and the intensity autocorrelation function are introduced, followed by ferroelectric case studies demonstrating how polarization switching and phase transition dynamics can be extracted from XPCS measurements. The influence of the probed q-range experimental conditions such as X-ray transmittance is examined for data interpretation. These elements are consolidated into practical guidelines for the reliable analysis of XPCS data.

Lead-free (Bi_1/2Na_1/2)TiO₃ (BNT)-based incipient piezoelectrics are highly promising for high strain actuators, but the high electric fields (4 ~ 6 kV/mm) required for activation limit practical device integration. In the current literature, large strains are frequently attributed to local structural variations like microscopic core-shell architectures. This work systematically investigates an alternative pathway by introducing A-site Strontium (Sr) excess non-stoichiometry into 0.74(Bi_1/2Na_1/2)TiO₃‒0.26SrTiO₃ (BNST26) ceramics. Microstructural and X-ray diffraction analyses reveal highly dense, uniform matrices completely devoid of micro-scale core-shell boundaries or macroscopic symmetry distortions, revealing that Sr non-stoichiometry diverges from typical Bi-excess mechanisms. Interestingly, despite negligible variations in overall macro-scale strain behavior across the composition series, a peak normalized strain (S_max/E_max) of approximately 804 pm/V is achieved at a low driving field of 2 kV/mm for the 1 mol% Sr-excess specimen (x = 0.010). These results indicate that while Sr non-stoichiometry weakly influences nanoscale stability, it can be inferred that subtle modifications of local defect configurations optimize switching energy barriers, enabling high-strain, low-drive-field performance in lead-free relaxors.

This review offers a critical overview of recent developments in lead-free piezoelectric materials and flexible device architectures for self-powered wearable and Internet of Things systems. It examines the scientific and technological rationale for replacing conventional battery-dependent power sources with ambient mechanical energy harvesters, and it evaluates the relative merits of inorganic ceramics, organic polymers, and composite systems in achieving efficient electromechanical conversion under practical operating conditions. The discussion further considers compositional tuning, phase boundary engineering, microstructural optimization, and device-level integration as key strategies for improving piezoelectric output, mechanical compliance, durability, and manufacturability. By connecting fundamental materials design with application-driven device requirements, the review identifies the principal challenges and emerging directions necessary for the realization of reliable, scalable, and sustainable electronic platforms.

Citations

• Recent progress on piezoelectric and ferroelectric films for human-machine interactive smart devices
  Nagamalleswara Rao Alluri, Kwi-Il Park
  Materials Today Physics.2026; 68: 102243.     CrossRef
• Recent advances in piezoelectric energy harvesting: materials, configurations, optimization techniques, and emerging applications
  Mir Waqas Alam, Sohail Ahmad Parah, Farooq Ahmad Dar, Abdulrahman Aljasim, Chawki Awada, Rameez Ahmad Parra
  Journal of Materials Science: Materials in Electronics.2026;[Epub]     CrossRef

β-Ga₂O₃ is an ultra-wide bandgap semiconductor promising for high-power electronic applications; however, heteroepitaxial growth on sapphire is challenging lattice and symmetry mismatch. In this study, β-Ga₂O₃ thin films were grown on C-plane sapphire substrates with various off-axis angles (0–12°) using mist-CVD, and the influence of substrate miscut on structural and optical properties was investigated. All films grown at 900°C exhibited (-201) oriented β phase. The crystal quality was strongly dependent on the off-axis angle, with intermediate off-axis angles (Δ_a = 6–8°) showing the narrowest rocking curve width. Off-axis substrates promoted step-aligned growth behavior compared to on-axis growth. Optical measurements revealed enhanced transmittance and wider bandgap values (4.92–4.95 eV) for off-axis samples compared to the on-axis film (4.69 eV). The findings provide practical guidelines for optimizing heteroepitaxial β-Ga₂O₃ growth on low-cost sapphire substrates for high-performance device applications.

The dielectric and piezoelectric properties of the ferroelectric BaTiO₃ were measured and analyzed using both strong and weak electric field conditions. To measure the electric field induced polarizations and strains, a high voltage source and the measuring circuit were used and the dielectric constants were measured with an impedance analyzer. The spontaneous polarization of BaTiO₃ at room temperature was calculated as 17 μC/cm² based on the lattice structure and internal ion location, which is in good agreement with the experimental results. The polarization and strain hysteresis curve according to the electric field were analyzed in terms of lattice structure and ion position. The magnitude of remanent polarization is proportional to the offset distance of Ti⁴⁺ ion from the lattice center. The magnitude of dielectric permittivity is proportional to the degree to which Ti⁴⁺ ion can move freely inside the lattice. The magnitude of piezoelectric constant d₃₃ is proportional to how much Ti⁴⁺ ion distorts the lattice as it moves inside the lattice.

Polymer nanocomposites incorporating inorganic nanofillers have emerged as highly promising electromagnetic interference (EMI) shielding materials, combining mechanical compliance with robust conductive percolation networks. Carbon nanotubes (CNTs) are particularly attractive as conductive fillers because their high aspect ratio facilitates percolation at low loadings. Also, CNTs offer superior mechanical durability under deformation compared to rigid, fracture-prone metal nanowires. For EMI shielding, high electrical conductivity is critical as it enhances both reflection and absorption through efficient charge dissipation and conduction losses. However, achieving highly aligned conductive pathways without degrading the intrinsic electrical properties of CNTs remains a significant challenge. Here, we demonstrate a non-destructive magnetic surface-functionalization and alignment strategy. Using a polydopamine (PDA)-mediated route, pristine multiwalled CNTs are uniformly decorated with Fe₃O₄ nanoparticles (FMWCNTs). This enables highly effective magnetic field-driven alignment at fields as low as 10 mT, promoting the strategic formation of percolation networks. By optimizing the Fe₃O₄/MWCNT ratio for high saturation magnetization and uniform coverage, the aligned FMWCNTs exhibit significant electrical anisotropy, delivering a 10.7-fold higher electrical conductivity in the parallel configuration compared to the vertical configuration. These findings present a scalable, room-temperature platform for engineering directionally enhanced conductivity in polymer nanocomposites, with broad applicability in advanced EMI shielding, flexible electronics, and advanced packaging technologies.

Citations

• Interfacial Engineering of Composite Piezoelectric Fibers Via an Anchor-Chain Architecture
  Jun Liu, Qiao Zhou, Pengcheng Zhang, Shuying Hu, Fang Zhou, Shuangshuang Ren, Ting Guo, Leiying Miao
  ACS Applied Engineering Materials.2026; 4(8): 4367.     CrossRef

The 0.2Pb(Zn_1/3Nb_2/3)O₃-0.8Pb(Zr_0.5Ti_0.5)O₃ (0.2PZN-0.8PZT) ceramic system exhibits excellent piezoelectric properties; however, its high sintering temperature (~1,250°C) causes severe PbO volatilization, increases processing cost, and limits co-firing with low-melting-point electrodes in multilayer devices. In this study, LiBiO₂ was introduced as a sintering aid to enable lowtemperature densification of 0.2PZN–0.8PZT ceramics. The optimal composition of x = 0.3 mol% sintered at 1,050°C achieved d₃₃ = 367 pC/N, k_p = 0.54, and ε^T₃₃/ε₀ = 1,643. The Curie temperature was also enhanced to 347.8°C, compared with 297.2°C for the reference specimen sintered at 1,250°C. These results demonstrate that LiBiO₂ addition enables a 200°C reduction in sintering temperature while maintaining piezoelectric performance and improving thermal stability.

The phase transition of Li₃PO₄ solid electrolyte for secondary batteries in vacuum has been studied by using real-time synchrotron X-ray scattering. According to the vacuum heating results, the crystal β-Li₃PO₄ phase was stable only from room temperature to 400°C. The crystal γ-Li₃PO₄ phase appeared at 410°C and the crystal β-Li₃PO₄ phase completely disappeared at 430°C. The transition from the β-Li₃PO₄ to the γ-Li₃PO₄ phases occurred primarily at 410°C, which is 40°C lower than the transition temperature of 450°C in air. The decrease in the phase transition temperature in vacuum, compared to that in air, is attributed to a relatively high concentration of oxygen vacancies. As the isothermal annealing time at 390°C was increased to 8 hours, the β-Li₃PO₄ phase was completely transitioned into the γ-Li₃PO₄ phase. Our study revealed the detailed transition behavior from the β-Li₃PO₄ to the γ-Li₃PO₄ phases during real-time annealing in vacuum.

Smart windows capable of dynamically controlling light transmission are gaining increasing attention as a means of reducing building energy consumption while improving indoor comfort. However, indium tin oxide (ITO), the most widely used transparent electrode in such devices, suffers from poor mechanical flexibility due to its intrinsic brittleness, limiting its use in curved or flexible window applications. Here, we demonstrate a flexible ITO/DPP hybrid transparent electrode, fabricated by depositing a dimethyl sulfoxide (DMSO)-doped PEDOT:PSS (DPP) layer on ITO, that achieves markedly improved bending durability while maintaining electro-optical performance comparable to bare ITO. The hybrid electrode with an optimized DPP thickness of 120 nm exhibited a sheet resistance of 23.3 Ω/sq., about 20% lower than that of ITO (29 Ω/sq.), while maintaining comparable visible-range transmittance. A polymer-dispersed liquid crystal (PDLC) device fabricated with this electrode showed only a slight decline in driving voltage and transmittance relative to ITO. Notably, its resistance change under repeated bending at a curvature radius of 30 mm was only 25.1%, less than half that of ITO (51.6%). These results suggest that the ITO/DPP hybrid electrode is a promising candidate for transparent electrodes in curved and flexible smart windows and other flexible optoelectronic devices.

Multilayer ceramic capacitors (MLCCs) are essential for high-capacitance, miniaturized, and reliable electronic applications. This study examines the impact of layer stacking on the dielectric and electrical properties of MLCCs using a BaTiO₃-based dielectric with MgO, Mn₃O₄, Yb₂O₃, V₂O₅, and (BaCa)SiO₃ glass additives. MLCCs with 10 um-thick dielectric layers and varying Ni electrode layers (10, 30, 50, and 100 layers) were fabricated. The dielectric constant increases significantly up to 30 layers due to compressive stress and sintering densification but it becomes linear beyond 30 layers. Dissipation factor and ESR decrease with higher stacking due to improved sinterability, while breakdown voltage declines exponentially from defect accumulation and thermal stress. Insulation resistance decreases but stabilizes relative to capacitance. C-V results show stress-induced polarization suppression, which reduces the dielectric constant under high voltage. Optimized stacking and sintering conditions are crucial for MIL-PRF-32535 compliant MLCC designs.

Citations

• [100]-Oriented BaTiO₃ via reaction-mediated texturing with SrTiO₃ templates
  Nu-Ri Ko, Jinsung Chun, Kutak Lee, Chang Kyu Jeong, Wook Jo
  Journal of the Korean Ceramic Society.2026; 63(4): 574.     CrossRef
• Effect of BaZrO3 Addition on the Frequency and Temperature Dependent Dielectric Properties of BaTiO3-Based Ceramics
  Won-Su Lee, Jong Kyu Lee, Moon-Taek Cho, Jung Rag Yoon
  Journal of Electrical and Electronic Materials.2026; 39(5): 478.     CrossRef

Ocean waves are not only a sustainable renewable energy source but also provide valuable information for monitoring marine environments and natural hazards. In this study, we developed a CNT/SEBS-based self-powered marine monitoring sensor utilizing a mechano-electrochemical mechanism, enabling simultaneous ultralow-frequency wave sensing and electrical energy harvesting. The developed sensor generated an open-circuit voltage of up to 60 mV and a short-circuit current of 80 μA/cm² without an external power source by exploiting variations in electrical double-layer capacitance induced by changes in the electrode–electrolyte interface. The capacitance increased from 0.1 μF to 2.4 μF with increasing immersion area, demonstrating the effectiveness of the proposed sensing mechanism. Furthermore, the CNT/SEBS bilayer exhibited high electrical conductivity together with excellent stretchability and flexibility, maintaining stable electrical responses under repeated water-level fluctuations. The proposed mechano-electrochemical self-powered sensor provides a promising platform for next-generation autonomous marine monitoring systems and sustainable blue-energy harvesting technologies.

Dye adsorption is one of the most time-consuming processes in the fabrication of dye-sensitized solar cells (DSSCs), typically requiring approximately 24 h at room temperature. In this study, the effect of adsorption temperature and time on photovoltaic performance of DSSCs was investigated in order to reduce processing time and improve device productivity. Nanoporous TiO₂ photoelectrodes were immersed in N719 dye solution at 60°C for 3 h, 10 h, 17 h, and 24 h, and their performance was compared with that of cells sensitized at room temperature for 24 h. Photovoltaic characterization under AM 1.5 illumination showed that DSSCs sensitized at 60°C exhibited improved performance compared to those sensitized at room temperature. The device sensitized at 60°C for 3 h showed comparable or higher conversion efficiency than the reference cell sensitized for 24 h at room temperature. The improvement in device performance is attributed to enhanced dye adsorption kinetics resulting from increased reaction rate between the carboxyl groups of N719 dye molecules and hydroxyl groups on the TiO₂ surface. Electrochemical impedance spectroscopy analysis revealed reduced recombination resistance at the TiO₂/dye/electrolyte interface for cells sensitized at elevated temperature. UV–Vis absorption analysis confirmed increased dye loading on the TiO₂ surface for the 60°C condition. These results demonstrate that elevated temperature dye adsorption significantly reduces processing time while maintaining photovoltaic performance, providing an effective strategy for improving manufacturing efficiency of DSSCs.

Citations

• Enhanced charge transport characteristics of hydrothermally grown rutile TiO2 nanorod arrays for dye-sensitized solar cells
  Kyu Seop Choi, Hyung Jin Kim, Byungyou Hong
  Surfaces and Interfaces.2026; 98: 110402.     CrossRef

With the rapid expansion of electric vehicles (EVs) and energy storage systems (ESS), ensuring the operational safety of lithium-ion batteries has become a critical technical challenge. Conventional battery management systems (BMS) primarily rely on threshold-based rule logic, which is limited in detecting coupled anomalies and early-stage degradation patterns. In this study, a deep learning-based framework for multivariate anomaly detection is proposed using BMS sensor data, including voltage, current, temperature, state of charge (SOC), and state of health (SOH). Five representative fault scenarios were defined, including thermal runaway precursors, cell voltage imbalance, SOC inconsistency, internal resistance increase, and communication delay. The proposed CNN-LSTM model was compared with conventional Rule-based methods and machine learning models, including Isolation Forest, Autoencoder, and LSTM. Experimental results show that the proposed model achieved the highest performance, with an F1-score of 0.885, an AUC of 0.94, and a detection delay of 8.1 s. In contrast, the Rule-based method exhibited a significantly higher false negative rate of 42.0%, indicating limitations in detecting complex anomaly patterns. These results demonstrate that the proposed spatiotemporal deep learning approach can significantly improve the accuracy and responsiveness of battery anomaly detection. Furthermore, the proposed method is expected to contribute to enhancing safety, reliability, and predictive diagnostics in next-generation intelligent BMS platforms.

The rapid advancement of large-scale language models and artificial intelligence technologies has highlighted the importance of data processing efficiency. This study outlines a measurement optimization method for high-speed pulse equipment to accurately analyze the operating dynamics of ReRAM, a core hardware component for simulating neural networks. An optimized evaluation methodology combining connection compensation and a dual-channel configuration was established to minimize measurement errors caused by parasitic resistance and capacitance during pulse measurements using the Keithley 4200A-SCS and 4225-PMU modules, and to address HRS/LRS measurement errors caused by mismatches between the measurement range and source limits. The proposed precision measurement guidelines can be applied to the evaluation of semiconductor devices that require pulse measurements, such as transistors and DRAM.

Metamaterials, as artificially engineered structures with unconventional mechanical and acoustic properties, have recently emerged as a transformative platform for enhancing the capabilities of triboelectric nanogenerator (TENG) systems. Since the invention of TENG devices, extensive efforts have been devoted to improving charge density, output stability, and overall performance. Conventional performance optimization strategies mainly rely on device-level improvements such as surface chemistry modification, microstructuring, and nanopatterning. However, limited emphasis has been given to system-level development of smart self-powered intelligent systems. The integration of metamaterials into TENG devices opens a new era by enabling frequency-selective localization, mechanical impedance matching, and controllable deformation pathways. These engineered mechanical structures not only improve energy harvesting efficiency but also introduce new functionalities into the system. This review systematically summarizes recent advances in metamaterial-integrated TENG systems across four major application domains: (i) energy harvesting, (ii) acoustic telecommunication and acoustic-to-electric conversion, (iii) self-powered sensing, and (iv) vibration suppression and monitoring. Overall, the integration of metamaterials into TENG systems will pave the way for next-generation sustainable, intelligent, self-powered devices with diverse functionalities.

Citations

• Fabrication and performance of integrated self-powered PAAM hydrogel flexible pressure sensors
  Huaikuan Zang, Chao Hu, Pan Niu, Yong Zhang
  Materials Science in Semiconductor Processing.2026; 214: 110899.     CrossRef
• Highly Stretchable Multiphase Composite Piezoelectret With Large Longitudinal and Transverse Piezoelectric Sensitivity for Self-Powered Electromechanical Sensors
  Yanfeng Lyu, Tiantian Gao, Jian Li, Zheng Hu, Xunlin Qiu, Yanxun Xiang, Fu-Zhen Xuan, Wee Chen Gan, Dietmar Auhl
  IEEE Sensors Journal.2026; 26(18): 27090.     CrossRef

Cellulose nanofiber (CNF) has attracted significant attention as a next-generation insulating material due to its ecofriendly nature and outstanding functionalities. However, conventional kraft insulation paper suffers from limited dielectric breakdown strength and long-term reliability under high-voltage conditions, highlighting the need for alternative materials. In this study, kraft pulp was combined with five types of CNFs (A, B, C: wood-based / D, E: non-wood-based) to fabricate composite insulation papers, and their electrical and mechanical properties were systematically evaluated. The results showed that CNF incorporation generally enhanced density and tensile strength, while certain types contributed to lowering dielectric constant and improving breakdown strength. Among the wood-based CNFs, type C exhibited the most balanced performance in terms of dielectric stability and mechanical reinforcement. Among the non-wood-based CNFs, type E demonstrated notable improvements in structural compactness and tensile strength, suggesting favorable reliability. Therefore, this study identifies CNF C among wood-based types and CNF E among non-wood-based types as the most promising candidates for insulation performance enhancement, suggesting their applicability as next-generation insulating materials for power equipment and ecofriendly electronic devices.

Silicon carbide (SiC), with its wide bandgap and strong resistance to radiation and thermal conditions, is a promising material for ultraviolet (UV) photodetector applications under harsh environments. In this study, porous SiC thin films with thicknesses of 20, 50, and 80 nm were fabricated on 4H-SiC substrates using aerosol deposition (AD), which enables roomtemperature film formation. The device with a 50 nm-thick film exhibited the highest photoresponse under UV-C illumination (260 nm), achieving a maximum photo-to-dark current ratio (PDCR) of 205.2, a responsivity of 0.058 A/W, an external quantum efficiency (EQE) of 27.71%, and a specific detectivity (D*) of 7.9×10¹¹ Jones. These results are attributed to an optimized balance between photon absorption and carrier transport in the porous structure. The findings confirm the potential of ADfabricated porous SiC films for highly sensitive and scalable UV photodetector applications.

Silicon carbide (SiC) power devices are attracting increasing attention for high-voltage and high-efficiency applications due to their superior material properties. However, achieving an optimal trade-off between specific on-resistance (Ron,sp) and breakdown voltage (BV) remains a key design challenge in planar MOSFET structures. In this study, twodimensional TCAD simulations were conducted to investigate the impact of varying the doping concentrations of the P-well (from 3 × 10¹⁷ to 6 × 10¹⁷ cm^-3) and JFET regions (from 1 × 10¹⁶ to 7 × 1016 cm^-3) on the electrical characteristics of 2.4 kVclass planar SiC MOSFETs. To maintain comparable BV conditions for 2.4 kV operation, two groups with P-well doping concentrations of 4.5 × 10¹⁷ cm^-3 and 5.3 × 1017 cm^-3 were analyzed and compared. When the P-well and JFET doping concentrations were 4.5 × 10¹⁷ cm^-3 and 1.5 × 10¹⁶ cm^-3, respectively, the simulated Ron,sp and BV were 1.41 mΩ·cm² and 3,150 V. In contrast, with P-well and JFET doping concentrations of 5.3 × 10¹⁷ cm^-3 and 5.0 × 10¹⁶ cm^-3, the Ron,sp was reduced to 1.31 mΩ·cm² while the BV slightly increased to 3,200 V. Based on these results, an optimized device structure was proposed, demonstrating its potential for integration into high-voltage SiC-based power systems. This study provides practical design insights and is expected to contribute to the advancement of wide bandgap semiconductor technologies for next-generation power electronics.

Piezoelectricity refers to the phenomenon where mechanical stress is converted into electrical signals or, conversely, electrical signals are converted into mechanical stress. Ferroelectric materials, characterized by high dielectric permittivity and spontaneous polarization, retain their polarization even after the removal of an electric field. In such materials, poling plays a crucial role in enhancing the piezoelectric effect, with the process of aligning dipoles being known as poling. This review focuses on studies that have compared and analyzed the enhancement of piezoelectric properties in ceramics and polymers through two representative poling methods: AC poling (ACP) and DC poling (DCP). Even within the same category of ceramics or polymers, variations in piezoelectric properties are observed based on the material type, poling method, and poling conditions. Under certain conditions, ACP has been shown to provide superior poling effects compared to DCP. Through this review, we propose that ACP has the potential not only to replace the traditionally used DCP in the poling of piezoelectric materials but also to serve as a more effective method. This could spark increased interest in the study of poling methods for piezoelectric polymers, a field that has received relatively less attention.

Citations

• Research Progress of Candidate Vibration Measurement Ceramic Materials and Intelligent Cutting Tools
  Zhenrong Sun, Chuanzhen Huang, Hanlian Liu, Zhenyu Shi, Dun Liu, Zhen Wang, Longhua Xu, Shuiquan Huang
  Journal of the American Ceramic Society.2026;[Epub]     CrossRef

Quantum dots (QDs) are semiconductor nanocrystals with sizes on the order of several nanometers, whose bandgaps can be tuned by controlling the particle size. Owing to this bandgap tunability, QDs can absorb near-infrared (NIR) and short-wave infrared (SWIR) light, spectral regions that are difficult to access with conventional silicon-based devices. However, colloidal QDbased infrared photodetectors still suffer from intrinsically high dark current, trap-induced noise, and limited response speed. As a result, they exhibit fundamental performance gaps in terms of detectivity and speed–bandwidth product compared to epitaxial infrared detectors, highlighting the need for structural and architectural design strategies to overcome these limitations. In this review, we discuss recent advances in enhancing the spectral selectivity and sensitivity of infrared photodetectors through three-dimensional optical architectures, including metasurfaces and metamaterials. We focus in particular on design strategies and the underlying mechanisms responsible for performance enhancement, and we outline how structural approaches can be leveraged to effectively control the sensitivity and wavelength selectivity of QD-based infrared detectors.