This study explores the use of laser ablation technology for creating on-demand shadow masks, which are essential in the fabrication of thin film transistor (TFT) devices. Traditional methods for producing shadow masks often encounter significant challenges, such as high costs, lengthy production times, and difficulties in achieving fine, high-resolution patterns. To address these issues, this study introduces a method for manufacturing shadow masks using fiber laser-based laser ablation. Key laser parameters, including frequency and power, were optimized throughout the research. Systematic experimentation revealed that a frequency of 20 kHz and a power output of 14 W enabled the precise and uniform creation of patterns with a 50 μm channel spacing. When these custom shadow masks were employed in the TFT fabrication process, the resulting devices exhibited stable and reliable electrical performance. The findings suggest that laser ablation-based on-demand shadow mask technology offers a cost-effective and flexible solution for producing large-area, high-resolution TFTs. Additionally, this approach significantly reduces the prototyping cycle, making it ideal for rapid development and iterative testing in research and development environments.

In this study, we demonstrate a synergistic enhancement of photoluminescence (PL) in an atomically thin molybdenum disulfide (MoS₂) monolayer using a dual-laser-beam-assisted chemical modification method. A continuous-wave (CW) green laser, directed perpendicularly at the MoS₂, locally raises the temperature and induces the formation of sulfur (S) vacancies, resulting in a significant increase in PL intensity. Subsequently, a UV nanosecond laser beam laterally illuminates the area above the MoS₂ layer, breaking chlorine molecules and introducing chlorine radicals without damaging the sample. This process further enhances the PL in the region previously affected by S vacancies. The binding energy of chlorine atoms to S-vacancy sites is greater than that to the pristine MoS₂ surface, facilitating more effective p-type doping. The stronger interaction at the defect sites created by the CW laser contributes to the observed synergistic PL enhancement. Our approach presents a novel method for precise and spatially selective chemical doping in two-dimensional (2D) van der Waals (vdW) materials.

Intrinsically stretchable electronics enable seamless integration with dynamic biological tissues and curved surfaces, making them vital for next-generation wearables, biointerfaces, and intelligent robotics. Yet, precise, high-resolution patterning of stretchable electrodes and circuits remains challenging, limiting practical applications. Traditional lithography offers excellent resolution but is hindered by thermal and chemical incompatibilities with soft substrates. Consequently, alternative approaches such as soft lithography, laser-based patterning, printing methods, and electrospray deposition have gained importance. Soft lithography provides an economical, low-temperature option suitable for delicate materials like liquid metals. Laser-based techniques deliver high resolution and design flexibility but require careful parameter tuning for specific substrates. Mask-free printing methods, including direct ink writing and inkjet printing, enable versatile patterning of complex geometries, while electrospray deposition supports precise, non-contact patterning on stretchable surfaces. Collectively, these techniques advance the fabrication of robust stretchable displays, wireless antennas, and bioelectronic interfaces for accurate physiological monitoring. Despite progress, challenges persist, particularly in achieving large-area uniformity, multilayer stability, and sustainable processing. Addressing these issues demands interdisciplinary collaboration across materials science, fluid dynamics, interfacial engineering, and digital manufacturing. This review highlights recent progress and remaining hurdles, offering guidance for future research in stretchable electronics.

This study examines how two key design parameters—the pre-stretch ratio and the thickness of the carbon nanotube (CNT) electrode—affect the actuation performance of dielectric elastomer actuators (DEAs). DEA samples are created with varying pre-stretch levels (50% and 125%) and different amounts of CNT spray coating (4 and 8 mg), and their threshold voltages and areal strains are quantitatively assessed. The experimental results indicate that higher pre-stretch ratios result in lower threshold voltages and greater areal deformations, while increased CNT thickness typically reduces actuator deformation due to enhanced mechanical stiffness. The combination of a high pre-stretch ratio and low CNT loading demonstrates improved electro-mechanical responsiveness at moderate voltages. These findings underscore the interconnected effects of structural and electrode design on DEA performance, offering practical design guidelines for optimizing soft actuator systems. This research lays a solid foundation for future applications of DEAs in haptic interfaces, wearable actuators, and soft robotics.

In this paper, we propose a novel method for controlling the anisotropic sliding behavior of droplets using multiscale hierarchical structures. First, we employed a silicon wafer mold containing micro-pillars and directional micro-line structures to induce the directional sliding of droplets. Additionally, we fabricated micro-cone patterns and integrated them into the structures to precisely control droplet movement. These two structures were replicated in polymer and subsequently fused into a single multiscale hierarchical mold through a partial curing process. The completed multiscale hierarchical surface was then replicated with PDMS to create anisotropy that governs the direction of droplet movement. We experimentally confirmed that the degree of sliding is influenced by the cone pattern. Our proposed structural design demonstrates that anisotropic wettability control is achievable even on surfaces made from a single material, indicating potential applications in various fields such as microfluidics, sensors, and functional surfaces.

Dry adhesives inspired by gecko footpads have garnered considerable attention due to their unique features, including strong yet reversible adhesion, self-cleaning properties, and repeatable use. However, scaling these microstructured adhesives from laboratory fabrication to continuous, high-throughput manufacturing poses significant challenges. In this study, we introduce a stepwise thermal patterning system designed for the scalable production of gecko-inspired dry adhesives on flexible substrates. This automated system combines sequential processes such as plate-to-plate micro-molding, rapid thermal curing, demolding, and roll-up of the patterned film. By raising the curing temperature to approximately 180^oC and employing an efficient stepwise imprinting method, we achieve fabrication speeds of up to 150 mm/min without compromising pattern accuracy. The system successfully replicates micropillar structures with a diameter of 15 μm and height of 15 μm, featuring 20 μm mushroom-shaped tips on flexible substrates. The resulting dry adhesives demonstrate stable pull-off strengths of 20-23 N/cm² and retain over 83.5% of their initial adhesion after 100,000 attachment–detachment cycles. These findings highlight the potential of our platform for reliable, high-throughput manufacturing of bio-inspired adhesives, paving the way for various industrial applications such as robotic manipulators, pick-and-place electronic assembly, and wearable devices that require repeated, residue-free attachment.

Smart farms and smart factories utilize various environmental measurement and task recognition sensors. For situations requiring simultaneous measurements, a multi-sensor module that combines several sensors into one unit is advantageous. This study focuses on integrating various sensors into a single module and proposing an optimal usage method to minimize the power consumption of a wireless multi-sensor module capable of remote measurements. Analysis of the power consumption of individual sensor components revealed that when the measurement interval exceeds one minute, power consumption can be reduced by over 50.3% by turning off sensors during idle periods. If real-time responsiveness is not essential, the most efficient approach is to keep the entire module in sleep mode during these idle periods. A practical experiment was conducted using a multi-sensor module equipped with temperature and humidity, illuminance, CO₂ concentration, and soil moisture sensors. When continuously powered, the module operated for 40 hours on a 3500 mAh Li-ion battery. However, by implementing sleep mode with a five-minute measurement interval, the operational duration extended to 562 hours.

Improving the interfacial stability between cathode active material (CAM) and solid electrolyte (SE) is essential for enhancing the performance and durability of all-solid-state batteries (ASSBs). One promising method to achieve this is through surface coating with a chemically stable ion conductor, which helps suppress interfacial side reactions and improve long-term cycling stability. In this study, we deposited a uniform LiNbO3 (LNO) protective layer on NCA using particle atomic layer deposition (Particle ALD). This technique utilizes a self-limiting growth mechanism to ensure precise thickness control. We characterized the structural and chemical properties of the coated CAM with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), confirming the successful formation of a uniform LNO layer. Electrochemical evaluations revealed that LNO@NCA exhibited significantly improved capacity retention, maintaining 68.1% after 50 cycles at a 1C rate, compared to just 56.5% for the uncoated sample. This enhancement is attributed to the LNO layer's effectiveness in mitigating electrochemical side reactions. These findings demonstrate that Particle ALD-derived LNO coatings are an effective strategy for stabilizing CAM|SE interfaces and extending the cycle life of high-energy ASSBs.

Detecting and analyzing defects in components or systems is crucial for maintaining high-quality standards in modern manufacturing and quality control. Recently, imaging-based defect detection methods have gained popularity across various engineering fields, highlighting their growing importance. Additionally, the integration of Artificial Intelligence (AI) to improve accuracy and efficiency is rapidly advancing. This paper presents a system that uses imaging to detect holes in CV joint boots, as these holes significantly affect the overall performance and durability of the system. Moreover, it introduces a method for enhancing detection performance by applying AI techniques. Validation tests on actual CV joint boots confirmed that the proposed method improves detection performance.

This study presents a dual-impeller air-cooled heat exchanger aimed at improving thermal management in electro-optical tracking systems operating under high power density. Two geometric modifications were introduced to enhance flow characteristics and heat transfer performance: the curvature of the center plate and the integration of a pin-fin structure at the outlet. Through numerical simulation, the improved model demonstrated more efficient internal flow compared to the original model, achieved through enhanced inflow characteristics and reduced flow separation. The pin-fin structures induced localized turbulence and recirculation zones, contributing to an increased thermal exchange surface area and longer effective heat transfer time. Consequently, the outlet temperature of the internal system decreased by an average of 1.4°C across various rotational speeds, resulting in a 5.9% increase in heat exchanger efficiency compared to the original model. Overall, this study shows that structural enhancements in heat exchanger design can significantly improve the cooling performance of high-power electronic systems, suggesting practical applicability for advanced thermal management solutions.

The purpose of this study is to evaluate the deformation behavior of 3D printed specimens using the small punch tensile test method. Traditional tensile tests for assessing mechanical properties require a significant amount of material to produce uniaxial tensile specimens. In contrast, the small punch test method only requires 10 x 10 x 0.5 mm (width x length x thickness) thin plate specimens, providing a substantial economic advantage in specimen sampling and production. This method is particularly beneficial when it is impossible to produce specimens of the same size as uniaxial specimens, as it allows tensile testing with just the minimum sample required. In this study, we utilized fused deposition modeling 3D printing and considered various 3D printing parameters, such as layer height and volume fraction, while manufacturing the specimens. We then compared and analyzed the effects of these variables on tensile strength as measured by the small punch tensile test. Furthermore, we focused on investigating the applicability of this method to the deformation behavior of 3D printed specimens. We also examined the impact of laminating conditions, including layer height, printing speed, and laminating direction, on the failure modes observed after the small punch tensile test.