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.
Wearable temperature sensors are becoming increasingly important for continuous health monitoring, personalized healthcare, and biointegrated electronic systems. However, conventional temperature-sensing platforms often suffer from limited thermal sensitivity, insufficient mechanical compliance, and unstable performance under repeated deformation, making it difficult to detect subtle physiological temperature variations in real time. Here, this tutorial status report presents a fabrication strategy for highly sensitive wearable temperature sensors based on gold-doped crystalline silicon nanomembranes. Gold diffusion into crystalline silicon introduces deep-level impurity states that modulate the Fermi level and shift the freeze-out region toward the physiological temperature range, enabling an ultrahigh negative temperature coefficient of resistance. By integrating the gold-doped silicon nanomembrane with a polyimide-supported ultrathin platform, neutral mechanical plane design, and serpentine mesh interconnects, the resulting device can provide high thermal sensitivity, fast response, conformal skin attachment, and stable operation under mechanical deformation. This fabrication approach is expected to broaden the use of impurity-engineered silicon nanomembranes in next-generation wearable sensors, flexible bioelectronics, and multifunctional healthcare monitoring systems.
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.
This study proposes an optimization strategy for the over-current protection (OCP) parameters of a lithium iron phosphate (LiFePO₄, LFP) battery system used in electric golf carts operating under high motor-load conditions. Real-world hillclimbing tests were conducted under four clearly defined payload/passenger conditions to analyze the transient discharge-current pro-file, voltage sag, and cell-temperature response. The maximum discharge current reached -238.2 A under the 200 kg cargopayload and one-passenger condition, and the current interval exceeding 150 A lasted up to 27 s. The maximum instantaneous power was 11.05 kW. Thermal analysis showed that the cell-temperature rise was within 2°C and the maximum measured cell temperature was 22.3°C. Linear regression of voltage and current yielded R² = 0.9368 and dV/dI = 0.0126 Ω, which was used as the DC internalresistance estimate. Based on these quantitative results and the cell specification limit of 300 A continuous discharge, the OCP threshold was reviewed from 250 A to 280 A to improve driving continuity while remaining below the allowable continuous-discharge current. EIS-based SOH estimation and the AI-BMS variable protection logic are presented as an extension framework for reflecting temperature and aging effects in future OCP-setting decisions.
This paper reviews the energy yield enhancement characteristics of bifacial photovoltaic systems combined with solar tracking, focusing on their performance relative to conventional monofacial fixed-tilt configurations. The fundamental mechanisms of yield improvement are summarized, highlighting the largely additive contributions of solar tracking, which increases front-side irradiance, and bifacial modules, which utilize rear-side reflected and diffuse radiation. Reported results from previous studies indicate that bifacial systems with single-axis tracking typically achieve 25–35% higher annual energy yield compared with standard monofacial fixed-tilt systems, with variations depending on environmental and design conditions. Key design and environmental considerations influencing system performance are discussed to provide practical insights for the application of bifacial tracking systems in utilityscale photovoltaic installations.
This paper proposes a circular sequential lighting control method to reduce current imbalance and luminance deviation among multiple LED modules in AC-powered LED lighting systems. Conventional fixed-sequence lighting control repeatedly prioritizes the same LED modules in every rectified voltage cycle, which leads to unequal current distribution, luminance non-uniformity, and the accelerated degradation of specific modules during long-term operation. To address these limitations, a circular sequential lighting strategy is introduced, in which the lighting order is cyclically rotated at every rectified cycle, ensuring that all LED modules experience equal lighting opportunities. A prototype AC-LED lighting system consisting of four series-connected LED modules was implemented and experimentally evaluated. The results demonstrate that, while the conventional fixed-sequence method produces a maximum average current deviation of up to 1.6 mA among modules, the proposed method equalizes the average current across all modules to approximately 17.1 mA. Furthermore, the flicker index remains at 0.13, which is comparable to that of the conventional method, indicating that luminance uniformity is improved without degradation of optical performance. The proposed circular sequential lighting control effectively distributes electrical stress, enhances luminance uniformity, and improves long-term reliability, making it a practical and efficient solution for high-quality AC-LED lighting applications.
Bismuth layer-structured ferroelectrics with high Curie temperatures have recently attracted significant attention as promising candidates for high-temperature piezoelectric applications. However, the conventional solid-state reaction method entails high-temperature processing that induces bismuth volatilization, thereby degrading device reliability. In this study, we employed a co-precipitation method enabling atomic-level mixing to significantly lower the synthesis temperature of Nb/Tadoped Bi4Ti3O12 ceramics compared to the solid-state reaction method. Experimental results demonstrated that the coprecipitation method yielded a pure single phase at 600℃ without intermediate phases. Furthermore, the synthesized nanopowders, with an average size of 100 nm, lowered the onset temperature of sintering shrinkage to 650℃, approximately 200℃ lower than that of the solid-state counterpart. The low-temperature synthesis process proposed in this work is expected to contribute to the performance enhancement of high-temperature piezoelectric devices by effectively suppressing bismuth volatilization and ensuring compositional stability.
(La1-xBixSr0.3)FeO₃ ceramics exhibiting excellent magnetoresistance were synthesized via the conventional solid-state reaction method. The structural and electrical properties were investigated as a function of Bi3+ content to evaluate their potential application as temperature sensors. And the sintering temperature and time were 1,200℃ and 4 h, respectively. The structural and electrical properties were investigated as a function of Bi content. With increasing Bi substitution, a slight enhancement in both average grain size and relative sintered density was observed. In particular, the specimen with x = 0.3 exhibited an average grain size of approximately 0.82 μm. All samples demonstrated negative temperature coefficient of resistance (NTCR) behavior, and the electrical resistivity decreased with increasing Bi content. The resistivity of the (La0.4Bi0.3Sr0.3)FeO₃ composition was 4.68 mΩ-cm at 25°C. Additionally, the temperature coefficient of resistance (TCR) and the B25/75-value, which quantify the sensitivity of resistivity to temperature variations, were found to increase with Bi content. (La0.4Bi0.3Sr0.3)FeO₃ sample exhibited a TCR of 0.43%/°C and a B25/75-value of 1,096 K at room temperature. The electrical conduction mechanism of the (La1-xBixSr0.3)FeO₃ system was well described by the small polaron hopping model, wherein thermally activated charge carriers hop between localized Fe-O-Fe sites via electron-phonon interactions.
κ-phase Ga₂O₃ is a wide-bandgap semiconductor that has attracted attention for power and optoelectronic device applications. However, its crystal quality and optical properties are highly dependent on the growth temperature, which motivates the need for a systematic study. In this work, κ-Ga₂O₃ thin films were grown on AlN/sapphire templates using mist-CVD at different temperatures. At lower temperatures (400℃), films exhibited incomplete crystallization and partial opacity, whereas higher growth temperatures (500-700℃) produced transparent films with improved properties. The bandgap was found to increase with temperature, consistent with reported values for 600-700℃, and XRD/XRC analysis confirmed that crystal quality improved with higher growth temperature. AFM analysis further revealed reductions in surface roughness and grain size variation at elevated temperatures. These findings indicate that an optimal growth window of 600-700℃ enables high-quality κ-Ga₂O₃ films, with potential implications for integrating this material on other hexagonal substrates such as SiC and GaN.
NTC (negative temperature coefficient) thermistors are semiconductor ceramics whose resistance decreases with increasing temperature, making them essential components in various temperature sensing applications. Typically, ceramic materials are sintered at high temperatures exceeding 1,150°C. However, in laminated devices incorporating internal electrodes, co-sintering can lead to cracking and mechanical failure due to mismatches in the thermal expansion coefficients between the ceramic layers and metal-based electrodes. Moreover, the use of noble metal electrodes increases production costs. To address these challenges, a low-temperature sintering approach is required. Previous studies have demonstrated that incorporating glass frit can reduce the sintering temperature of ceramics, although this often results in increased electrical resistance. In this study, NiMnCoO₄ (NMC) ceramics, as a representative NTC thermistor composition, were prepared with the addition of 10 wt% glass frit. To mitigate the resulting increase in resistivity, trace amounts (1 wt%) of various metal oxides, including CuO, ZnO, and MnO, were introduced. Among these, the addition of CuO notably decreased both the resistivity and B constant values. In contrast, MnO had little effect on resistivity, while ZnO led to an increase. With respect to the B25/85 constant, samples containing MnO and ZnO exhibited higher values than those without metal oxide additives. These findings indicate that the incorporation of 1 wt% CuO is effective in reducing the increased resistivity in NMC ceramics subjected to low-temperature sintering via glass frit addition.
With the ongoing rise in renewable energy demand, offshore wind farms are rapidly expanding, increasing the need for advanced development and diagnostic techniques for submarine cables. These cables are essential for efficient and reliable power transmission. A critical issue with these submarine cables is the formation of internal hot spots, which can deteriorate the insulation’s performance and negatively impact the overall reliability of offshore wind energy infrastructure. This research focuses on developing an innovative real-time monitoring system to detect hot spots within submarine cable insulation under varying electrical loads. Experimental tests were conducted on a 66 kV-grade wet-type submarine cable specifically designed for offshore wind applications, applying incremental current loads ranging from 200 A to 500 A. Temperature changes within the insulation due to the generated heat were continuously monitored using Distributed Temperature Sensing (DTS). Additionally, to evaluate the DTS system’s precision, repeatability, and overall reliability, the measured temperatures were compared against values obtained from validated spot-type sensors. Experimental results showed a discrepancy of less than 1% between DTS and spot-type sensor measurements at a reference temperature of 60℃, demonstrating the high accuracy and reliability of the developed DTS-based monitoring system. The outcomes of this study suggest that the proposed monitoring system can significantly enhance the capability for early detection and continuous monitoring of hot spots, thereby improving the operational reliability of submarine cables employed in offshore wind energy installations.
The increasing demand for renewable energy is driving the rapid expansion of the offshore wind industry, leading to intensified research on subsea cables. These cables endure combined thermal, electrical, and mechanical stresses, with mechanical stress being a critical failure factor. Environmental changes, such as seabed scouring, free spans, and seismic activity, accelerate cable degradation by introducing additional dynamic loads. Conventional monitoring systems primarily track thermal stress, lacking the ability to assess mechanical impacts. This study develops a system to simultaneously measure thermal and mechanical stress in subsea cables. Laboratory experiments confirm the system’s reliability, showing a temperature measurement error within 0.8% at 60℃ and a strain measurement error within 13% at 378 με. The proposed system aims to enhance failure prediction and maintenance strategies for offshore wind subsea cables.
This study developed a dielectric composition for high-capacitance MLCCs with C0G and U2J temperature compensation characteristics (Class I) under reducing conditions. The potential application of this composition in highpermittivity class I MLCCs was examined. Using (Ba₀.₂₄Ca₀.₁₆Sr₀.₆)(TiₓZr₁₋ₓ)O₃. XRD analysis showed that secondary phases like Sr₂TiO₄ and TiO₂ formed at higher Ti content, affecting the stoichiometric balance. Adjusting the Ti/Zr molar ratio resulted in a dielectric constant of 41.2 ~ 105, a dielectric loss of 0.082 ~ 0.174%, and insulation resistance above 1.6 × 1013 ohms at 25℃. The TCC shifted from C0G to U2J as the Ti/Zr ratio increased, but the composition enabled the design of high-capacitance and high-voltage MLCCs with favorable dielectric and electrical properties.
Porous polymeric structures with piezoelectric properties have attracted considerable attention in the fields of biomaterials and tissue engineering due to their ability to convert mechanical stimuli into electrical signals. However, conventional fabrication methods for porous structures often face limitations in controlling pore architecture, maintaining structural uniformity, and achieving process reproducibility, in addition to requiring complex processing conditions. To address these issues, we propose a facile and reproducible fabrication method for porous poly (vinylidene fluoride) (PVDF) piezoelectric sponges using molded sugar cubes as sacrificial pore templates. By adjusting the particle size of the sugar templates, the pore size and distribution of the sponges could be effectively controlled, and a uniform open-pore network was achieved. The fabricated sponges were evaluated with a focus on pore morphology, mechanical behavior, and piezoelectric performance depending on the sugar particle size, and these evaluations confirmed the structural properties and functional efficacy. This study presents a simple and reproducible fabrication strategy along with a quantitative analysis method for porous structures, which is expected to enhance process accessibility and practical applicability in the development of piezoelectric polymer-based biomaterial platforms.
NTC thermistors are essential components widely used for temperature sensing in various electronic sensor applications. However, conventional NTC thermistor ceramics typically require high sintering temperatures above 1150℃, necessitating the use of high-cost noble metal electrodes such as palladium (Pd) or platinum (Pt), which increases the overall manufacturing cost. In this study, low-melting-point oxides were successfully introduced as sintering aids to reduce the sintering temperature of NiMnCoO₄-based semiconducting ceramics. As the additive content increased, the B constant and average grain size exhibited an increasing trend, while the sample containing 5 wt% additives showed the lowest room-temperature resistivity. Furthermore, samples sintered at 1000℃ demonstrated slightly higher room-temperature resistivity and B constant values compared to those sintered at 1150℃. These results confirm that the addition of low-melting-point oxides is effective in lowering the sintering temperature of NiMnCoO₄ ceramics, suggesting the potential for reducing production costs and improving design flexibility in thermistor fabrication.
The continuous and long-lasting monitoring of physiological signals induced from the human body is crucial for health monitoring, disease diagnosis, and treatment. In this study, we have reported the Seebeck effect-based flexible selfpowered temperature sensor which can convert the electric signals from lateral temperature difference. For demonstrating temperature sensor arrays, the p-type thermoelectric (TE) composite films were fabricated by dispersing the Bi0.5Sb1.5Te3 (BST) powders inside poly-vinylidene fluoride matrix and subsequently attached to the patterned electrode foils. The inorganic BST powders-embedded TE composite films with activated area of 0.5 × 1 cm² harvest a maximum voltage of 1.7 mV, a maximum current of 5.6 mA, and an output power of 2.6 nW from the temperature gradient (ΔT) of 20 K. Finally, the fabricated selfpowered temperature sensor array well detected the pattern images of external thermal source of ΔT = 20 K. This study manifests flexible temperature sensor array which paves the way for further advancements in this field.
The composite specimens of (1-x)(La0.7Sr0.3)MnO₃-xBaTiO₃ (x = 0.05 ~ 0.3) were synthesized using the conventional solid-state reaction method, and the sintering temperature and time were 1,300℃ and 3 hours, respectively. As a result of observing the structural characteristics, the crystal structure of LSMO-BT solid solution was shown in which the rhombohedral LSMO phase and the tetragonal BT phase were separated and distributed, respectively. And fine grains having relatively small and uniformly distributed grains with sizes ranging from approximately 0.4 to 0.5 μm and pores within the specimens were observed. Notably, variations in the BT content did not significantly affect the grain size or porosity distribution, and a relative density of about 90% or more was shown. The resistivity, temperature coefficient of resistance (TCR), and B25/65-value of the 0.7LSMO-0.3BT specimen at room temperature showed the highest values of 1.94 Ω-cm, 0.292 %/℃, and 464 K, respectively. The resistivity behavior of the LSMO-BT composites matched well with the small polaron hopping conduction model.
Recently, oxide semiconductors have assumed a pivotal role in electronic displays and transparent electronic devices such as amorphous indium gallium zinc oxide (a-IGZO), characterized by high electron mobility and excellent stability. a- IGZO is very suitable for next-generation applications such as flexible displays because it is possible to manufacture highperformance transistors even at low temperatures. However, since the electrical properties tend to deteriorate in hightemperature environments, research aimed at improving thermal stability is needed. In this study, a low-temperature plasma annealing process was introduced to improve the high-temperature stability of the a-IGZO thin film. This process enhances electron mobility by reducing defects in the a-IGZO film and provides stable device performance even under high-temperature conditions. As a result of the experiments of 5 min, 10 min, 15 min, and 20 min, the a-IGZO TFT, which was subjected to plasma annealing at 160℃ for 5 min, showed the best electrical performance, especially in charge mobility and current-voltage characteristics. The technical potential for improving the performance of a-IGZO-based display device was emphasized, and the foundation for applying this power generation to flexible displays and next-generation electronic devices was laid. Future research will focus on determining the optimal annealing conditions by exploring various temperature ranges and plasma parameters to integrate these results into the actual device manufacturing process. These efforts are expected advance significantly to advancing next-generation high-performance display technology.
This paper presents a comparative analysis of the fire detection characteristics between conventional fire detector sensors and an Si-based color sensor. With the rapid industrial development in modern society, the concentration of urban populations and the expansion of building sizes have accelerated, leading to an increased frequency of large-scale fires. As a result, the importance of fire detection technologies has been emphasized. However, conventional detectors continue to experience issues such as false alarms and malfunctions. To address these challenges, a novel fire detection technology utilizing an Si-based color sensor, which is effective for fire detection, is proposed. To evaluate the fire detection performance of each sensor, a fire detection test apparatus was developed, and experiments were conducted separately under smoke and flame conditions to analyze the fire detection capabilities of the Si-based color sensor, temperature sensor, and flame detection sensor. The experimental results demonstrated that detection speed and sensor values varied depending on the type of combustible material. Specifically, in the smoke and flame tests, the Si-based color sensor detected fires 26.7 and 43.7 seconds faster than the temperature sensor, and 26.6 and 15.4 seconds faster than the flame detection sensor, respectively. Therefore, it was confirmed that the Si-based color sensor proposed in this study is an effective detection technology that is expected to provide improved performance compared to conventional fire detectors.
Hazardous gas leakage incidents rank among the most serious safety accidents, leading to significant loss of life, extensive property damage, and severe environmental pollution. This paper describes an innovative IoT-based Assembly Double Pipe System (IADPS) designed for the prevention, early detection, and automated isolation of toxic gas leaks. The proposed system features a double-layered pipe design, with nitrogen charged between the inner and outer pipes, and gas detectors installed at strategic locations. This configuration is intended to prevent pipe corrosion, suppress ignition caused by escaping gas, and facilitate the early detection of gas leaks, thereby mitigating the risk of safety accidents. Furthermore, the system includes a comprehensive real-time monitoring system for pipe integrity and gas leakage, as well as an automated gas leakage detection and isolation system to quickly respond to any incidents.
The display industry has recently been at the forefront of innovative advancements in modern electronic devices. Technological progress such as flexible display holds significant potential across various application fields, particularly in wearable devices and rollable displays. A low-temperature process is essential for fabricating such displays. One of the key technologies in displays is the thin film transistor (TFT), with amorphous indium gallium zinc oxide (a-IGZO) receiving particular attention. a-IGZO is widely applied in high-performance displays due to its high charge mobility and stability. While a thermal treatment above 350℃ is typically required to maximize the electrical performance of a-IGZO TFTs, such high temperatures pose challenges for utilizing polymer substrates like plastics. Here, we thesis investigates the simultaneous lowtemperature plasma annealing process to develop next-generation high-performance flexible display devices. To define the optimal temperature, devices were fabricated and analyzed at varying temperatures of 40℃, 80℃, 120℃, and 160℃. Experimental results indicated that devices fabricated at 160℃ and 80℃ exhibited superior performance, with those at 160℃ demonstrating better performance in terms of current ratio, threshold voltage, and subthreshold swing. These findings confirm that the simultaneous low-temperature plasma annealing process is effective for next-generation high-performance displays.
The transparent electrode characteristics of the SnO₂/AgNi/SnO₂ (OMO) multilayer structures prepared by sputtering were investigated according to the annealing temperature. Ni-doped Ag of various compositions was selected as the metal layer and heat treatment was performed at 100~300℃ to evaluate the thermal stability of the metals. The manufactured OMO multilayer structures were heat treated for 6 hours at 400~600℃ in an N₂ atmosphere. The structural, electrical, and optical properties of the OMO structures before and after annealing were evaluated and analyzed using a UV-VIS spectrophotometer, 4-point probe, XPS, FE-SEM, etc. OMO with Ni-doped Ag shows improved performance due to the reduction of structural defects of Ag during annealing, but OMO structure with pure Ag shows degradation characteristics due to Ag diffusion into the oxide layer during high-temperature annealing. The figure of merit (FOM) of SnO₂/Ag/SnO₂ was highest at room temperature and gradually decreased as the heat treatment temperature increased. On the other hand, the FOM value of SnO₂/AgNi/SnO₂ mostly showed its maximum value at high temperature(~550℃). In particular, the FOM value of SnO₂/Ag-Ni (3.2 at%)/SnO₂ was estimated to be approximately 2.38×10-2 Ω-1. Compared to transparent electrodes made of other similar materials, the FOM value of the SnO₂/Ag-Ni (3.2 at%)/SnO₂ multilayer structure is competitive and is expected to be used as an alternative transparent conductive electrode in various devices.
Due to changes in the form factor of display panels and touch screen panels in various devices, capacitive touch systems have evolved to address various issues such as low power consumption, noise immunity, and small chip size. Furthermore, some devices have applications that use a stylus. Since the stylus operates similarly to a finger touch, it encounters similar issues. Recent research trends focus on addressing key issues such as noise, which is primarily caused by the self-capacitor formed between the display cathode and the touch screen panel. In this paper, Various research papers discussing methods to eliminate external noise will be reviewed. These advancements enhance noise immunity in touch systems, making it easier to use thinner and more flexible panels. These progress make touch technology more versatile and reliable in various applications.
Pil Hong Jeong, Beom Jin Kim, Yeong Jin Kim, Dong Gyu Jeon, Hyo Min Kim, Jae Hyeon Kim, Hyeong Min Kim, Gyu Seong Lee, Kawan Anil, Eung Ryul Park, Soon Jae Yu, Min Jun Ann, Do Won Hwang
J Electr Electron Mater 2024;37(4):394-399. Published online July 1, 2024
An irradiator is developed using two UVA wavelength ranges of SMD LEDs as a curing light source. This module has dimensions of 545×111×300 mm3 and is equipped with a TIR bar-shaped lens made of PDMS silicone resin. The developed irradiator offers high uniformity, with 89% in the centerline of the horizontal axis direction, for two different wavelength ranges of 365 nm and 385 nm. The radiation intensity from the light source module shows highly directional characteristics, and the irradiator provides a maximum irradiance of 1,634 mW/cm2 at a working distance of 50 mm. During the initial 5 minutes of operation, the irradiance experiences a rapid decrease. However, this issue is addressed by optimizing the LED’s current reduction characteristics and managing the Transistor’s temperature rise in the constant current circuit. After continuous operation for approximately 60 minutes. The highest temperature, near the central part of the irradiating surface, reaches 69.7℃, while the lowest temperature, near the edges, is 41.1℃.
The expansion of lithium-ion battery usage beyond portable electronic devices to electric vehicles and energy storage systems is driven by their high energy density and favorable cycle characteristics. Enhancing the stability and performance of these batteries involves exploring solid electrolytes as alternatives to liquid ones. While sulfide-based solid electrolytes have received significant attention for commercialization, research on amorphous-phase glass solid electrolytes in oxide-based systems remains limited. Here, we investigate the glass transition temperatures and sintering behaviors by changing the molecular ratio of Li2O/B2O3 in borate glass comprising Li2O-B2O3-Al2O3 system. The glass transition temperature is decreasing as increasing the amount of Li2O. When we sintered at 450℃, just above the glass transition temperature, the samples did not consolidate well, while the proper sintered samples could be obtained under the higher temperature. We successfully obtained the borate glass ceramics phases by melt-quenching method, and the sintering characteristics are investigated. Future studies could explore optimizing ion conductivity through refining processing conditions, adjusting the glass former-to-modifier ratio, and incorporating additional Li salt to enhance the ionic conductivity.
In this paper, the electrical properties of liquid insulating oil were analyzed by changing the ambient temperature change at 10℃ in-tervals from 0℃ to 30℃ through an insulation breakdown experiment in order to analyze the insulation performance of liquid in-sulating oil that varies according to temperature changes. As a result, it was confirmed through experiments that the lower the am-bient temperature, the higher the insulation breakdown voltage, depending on both the electrode shape and the electrode interval, and it was determined that the lower the ambient temperature, the higher the insulation performance of the liquid insulating oil.
With the recent development of emerging technologies, information acquisition and delivery between users has been actively conducted, and inorganic thin film transfer technology that effectively transfers various materials and devices is being studied to develop flexible electronic devices accordingly. This is aimed at innovative structural changes and functional improvement of electronic devices in the era of the Internet of Things (IoT). In particular, advanced technologies such as micro- LEDs are used to realize high-resolution flexible displays, and the possibility of heterogeneous integrated technologies can be presented by precisely transferring materials to substrates through various transfer process. This paper introduced physical, chemical, and self-assembly transfer methods based on inorganic thin film materials to implement heterogeneous integrated flexible semiconductor systems and introduces the results of application studies of semiconductor devices obtained through different transfer technologies. These studies are expected to bring about innovative changes in the field of smart devices, medical technology, and user interfaces in the future.
This research explores the development of [100]-textured barium titanate (BaTiO3, BT) ceramics using sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBiT) templates, aimed at leveraging the inherent high dielectric property of BT. However, the attempted texturing was unsuccessful, primarily due to bismuth diffusion from the NBiT templates into the BT matrix below the sintering temperature, at 1,000℃. Systematical exploration about the cause of the failure is involved and alternative approaches are proposed in detail to overcome the challenge. These findings contribute to the understanding of techniques and conditions for textured ceramic fabrication and highlight the need for further research in this area.
The low-temperature coefficient of resistance (TCR) is a crucial factor in the development of space-grade resistors for temperature stability. Consequently, extensive research is underway to achieve zero TCR. In this study, resistors were deposited by co-sputtering nickel-chromium-based composite compositions, metals showing positive TCR, with SiO2, introducing negative TCR components. It was observed that achieving zero TCR is feasible by adjusting the proportion of negative TCR components in the deposited thin film resistors within certain compositions. Additionally, the correlation between TCR and deposition conditions, such as sputtering power, Ar pressure, and surface roughness, was investigated. We anticipate that these findings will contribute to the study of resistors with very low TCR, thereby enhancing the reliability of space-level resistors operating under high temperatures.
The size of semiconductor devices has been scaled down to improve packing density and output performance. However, there is uncontrollable spreading of the dopants that comprise the well, punch-stop, and channel-stop when using hightemperature annealing processes, such as rapid thermal annealing (RTA). In this context, low-temperature deuterium annealing (LTDA) performed at a low temperature of 300℃ is proposed to reduce the thermal budget during CMOS fabrication. The LTDA effectively eliminates the interface trap in the gate dielectric layer, thereby improving the electrical characteristics of devices, such as threshold voltage (VTH), subthreshold swing (SS), on-state current (ION), and off-state current (IOFF). Moreover, the LTDA is perfectly compatible with CMOS processes.