Electrochromic microsupercapacitors (EC-MSCs) featuring in-plane interdigital electrodes are multifunctional energy storage devices capable of real-time visualization of their charge state within a compact footprint. In particular, redox-active organic EC molecules possess high optical modulation and high structural tunability, enabling diverse color expression and electrochemical properties. Despite these advantages, the correlation between the diffusive flux behavior of redox species and the resulting electrochemical performance within interdigitated electrode architectures remains unclear. In this study, we systematically elucidate the correlation between key factors governing diffusive flux, namely, electric field distribution and concentration gradient, and energy storage performance. The electrode gap size and redox species concentration were systematically varied, and the ionic motion and redox species transport during device operation were decoupled for separate analysis. Our results suggest that energy storage performance, while linearly dependent on the concentration gradient, can exhibit nonlinear behavior depending on the electric field distribution, highlighting the dominance of electric field configuration in diffusion-controlled EC-MSCs. This work provides a design framework for future development of compact and multifunctional energy storage systems.

Ultrathin Ag films are attractive embedded layers for oxide/metal/oxide (OMO) transparent conducting electrodes (TCEs), but their strong tendency to agglomerate below the percolation threshold severely degrades the optical and electrical performance. Here, we demonstrate that combining Ga alloying with oxidizing sputter deposition effectively suppresses agglomeration in ultrathin Ag-based films embedded in ITO/metal/ITO OMO-type TCEs on colorless polyimide substrates. By tuning the embedded metal composition, thickness, and oxygen flow ratio Phi, we identify an optimized condition in which a 5 nm Ag-Ga layer (Phi = 6%) forms a continuous, void-free conduction path, achieving a visible transmittance of 86-88% at 550 nm and a sheet resistance of 15.8 Omega sq-1. TEM/STEM-EDS and XPS analyses reveal that Ga alloying, interfacial Ga segregation, and controlled Ag/Ga oxidation act together to lower effective surface and interface energies and stabilize ultrathin Ag-Ga layers against agglomeration. As a result, the optimized ITO/Ag-Ga/ITO OMO-type TCE exhibits a high figure of merit, excellent mechanical flexibility, and strong resistance to high-temperature, high-humidity degradation and operates as a transparent heater, reaching application-relevant temperatures under modest bias.

This study investigates the optical properties of nine indium gallium zinc oxide thin films deposited under three oxygen partial pressures (OPP) (10%, 30%, 50%) and three working pressures (2, 5, 10 mTorr). Spectroscopic ellipsometry (SE) data were analyzed with the Cauchy-Urbach (CU) model to extract refractive index (n), extinction coefficient (k), and dielectric functions (epsilon(1), epsilon(2)). Thicknesses derived from SE agreed with stylus profiler measurements within 10%, confirming the CU model's reliability. Both n and k decreased with increasing working pressure, reflecting reduced electron density due to fewer oxygen vacancies. While n varied <1% at 623 nm across the OPP range, k and epsilon(2) were highly sensitive to oxygen incorporation, decreasing by similar to 54% at 623 nm as OPP increased from 10% to 50%. These results indicate that higher OPP and working pressures suppress oxygen-vacancy-induced sub-gap states, thereby lowering optical absorption in the visible range.

In this study, we present a novel capacitive flexible pressure sensor incorporating a liquid metal composite-based micropillar dielectric structure. The micropillar array was fabricated using UV laser etching, a simplified and efficient alternative to conventional lithographic techniques, significantly reducing processing time and complexity. To enhance the effective dielectric constant variation under applied pressure, we incorporated a gallium-based liquid metal (EGaIn), which features a low melting point (Tm = 15.5 °C), high electrical conductivity (3.4 × 106 S/m), and low toxicity. The sensitivity and pressure range of the sensor were systematically analyzed as a function of EGaIn content and micropillar aspect ratio (AR). The optimized sensor, with 15 vol % EGaIn and an AR of 1, demonstrated a high sensitivity of 2.07 kPa-1 in the low-pressure regime (<135 Pa). These results highlight the potential of the proposed liquid metal composite-based capacitive pressure sensor for applications requiring high-performance pressure sensing, such as electronic skin, augmented/virtual reality systems, and health monitoring applications.

Reliable and noninvasive monitoring of glucose remains a critical challenge for wearable healthcare devices. Conventional enzymatic sensors, while selective, suffer from limited stability and short operational lifetimes, highlighting the need for robust nonenzymatic alternatives. Here, we report a nonenzymatic, noninvasive glucose biosensor fabricated through the combination of laser irradiation (LI) and electroless plating (ELP). LI of a SnO2/polyurethane acrylate (PUA) composite selectively exposed catalytic sites, enabling uniform Cu/Ni/Au metallization via ELP. The resulting electrodes were well-formed, exhibiting low resistivity (21.94 ± 1.09 mΩ·cm) and strong mechanical stability, maintaining conductivity even after 100,000 folding cycles at a bending radius of 5 mm. Functionalization with catalytic Pt/C endowed the electrodes with high catalytic activity, yielding reliable cyclic voltammetry (CV) responses and superior glucose detection capability. Compared with a commercial electrode, the LI-ELP biosensor achieved nearly 18-fold higher sensitivity (16.3 ± 1.40 vs 0.92 ± 0.10 mA mM-1 cm-2) and improved linearity (0.96 vs 0.94) over the 0-0.5 mM glucose range. The superior performance is attributed to the enlarged active surface area, optimized electrode structure, and efficient catalyst utilization, which collectively reduced overpotentials and enhanced charge-transfer efficiency. Overall, these findings establish LI-ELP as an effective and scalable strategy for fabricating durable, conductive, and efficient electrodes, highlighting its strong potential for next-generation wearable biosensors and broader nonenzymatic electrochemical sensing applications.

A physical sensor with a sensing medium comprising multiparallel-connected (MPC) piezoresistive pathways in both the vertical and horizontal directions was developed to achieve improved sensing performance. The MPC sensing medium reduces the total resistance and offsets noise, offering enhanced signal stability and device reliability and providing a high-performance sensing platform. The signal change and gauge factor (GF) of the 3PW-5L strain sensor (comprising three lines and five layers of piezoresistive pathways horizontally and vertically, respectively) were, respectively, 5.9 and 4.7 times higher than those of the 1PW-1L sensor composed of a monosensing pathway; the hysteresis of the detected signal was also significantly reduced. The linearity of the detected signal increased from 0.912 for 1PW-1L to 0.995 for 3PW-5L, indicating a greater sensing reliability. The direction of the applied tensile strain was successfully detected using the MPC sensing medium with an orthogonal configuration. The MPC piezoresistive sensor composing vertically stacked piezoresistive pathways demonstrated excellent performance as a pressure sensor; the 3PW-5L pressure sensor afforded a GF of 0.121 ± 0.002 kPa-1 with a linearity of 0.998 under an applied pressure ≥16.4 kPa. The MPC piezoresistive physical sensor offers a superior sensing performance and should contribute to the future development of wearable sensors and electronic devices.

A highly flexible electrode was fabricated using eutectic gallium–indium (eGaIn) liquid metal combined with an ultraviolet (UV)-curable polyurethane acrylate (PUA) polymer. The eGaIn liquid metal electrodes prepared by a negative-type direct patterning technique using a UV pulse laser can eliminate the need for complex photolithography masks. The optimal UV pulsed laser peak fluence was ∼1.43 J/cm 2 to pattern and sinter the eGaIn/PUA composite electrode simultaneously. The laser-patterned eGaIn/PUA composite electrode under optimal laser conditions exhibited a remarkable electrical conductivity of 6.33 × 10 5 S/m with a patterning resolution of ∼40 μm. Moreover, the resistance of the electrode deteriorated by only 0.95% after 50 000 cycles of severe cyclic folding at a peak strain of 2.5% with a bending radius of 1 mm, demonstrating its exceptional flexibility and durability. These easily patterned eGaIn flexible electrodes through direct laser patterning techniques hold great promise for applications in wearable and flexible electronic devices that require extreme flexibility.

This paper proposes a novel rhombic dual-polarized and dual-band patch antenna array design for 5G mmWave mobile devices as an antenna-in-package (AiP). The proposed antenna consists of a stacked patch and a parasitic patch that are designed to operate at dual frequencies (28 and 39GHz). An asymmetric stack-up strategy is used to maximize antenna performance within the constraints of the form factor. To address the limitations of elongated asymmetrical structures, the rhombic patch is utilized to achieve dual-polarization capabilities. The RF front-end module (RFFE), which integrates the proposed AiP (1×4 array antenna), is also fabricated and tested for its gain and beam-steering performance. The results show a maximum gain of 10.4 dBi at the lower band (LB) and 11.0 dBi at the higher band (HB) with beam-steering capabilities of ±45 degrees in both bands.

Mesoporous metal oxides exhibit excellent physicochemical properties and are widely used in various fields, including energy storage/conversion, catalysis, and sensors. Although several soft-template approaches are reported, high-temperature calcination for both metal oxide formation and template removal is necessary, which limits direct synthesis on a plastic substrate for flexible devices. Here, a universal synthetic approach that combines thermal activation and oxygen plasma to synthesize diverse mesoporous metal oxides (V2O5, V6O13, TiO2, Nb2O5, WO3, and MoO3) at low temperatures (150-200 °C), which can be applicable to a flexible polymeric substrate is introduced. As a demonstration, a flexible micro-supercapacitor is fabricated by directly synthesizing mesoporous V2O5 on an indium-tin oxide-coated colorless polyimide film. The energy storage performance is well maintained under severe bending conditions.

Deformable and miniaturized energy storage devices are essential for powering soft electronics. Herein, we fabricate deformable micro supercapacitors (MSCs) based on eutectic gallium-indium liquid metal (EGaIn) current collectors with integrated graphene. The well-define interdigitated electrode patterning with controlled gap is successfully realized by using the laser ablation because of a strong laser absorption of graphene and EGaIn. By judicious control of gap size between neighboring interdigitated electrodes and mass loading of graphene, we achieve a high areal capacitance (1336 µF cm−2) with reliable rate performance. In addition, owing to the intrinsic liquid characteristics of EGaIn current collector, the areal capacitance of fabricated MSC retains 90% of original value even after repetitive folding and 20% stretching up to 1000 cycles. Finally, we successfully integrate deformable MSC with a commercial light-emitting diode to demonstrate the feasibility of MSC as a deformable power source. The fabricated MSCs operate stably under various mechanical deformations, including stretching, folding, twisting, and wrinkling.

High-k polymeric layers were prepared by combining various functional groups and were applied as gate dielectrics for practical organic field-effect transistors (OFETs). Crosslinking of the polymeric layers through UV-assisted organic azide fluorine-based crosslinkers induced dramatic improvements in the electrical performance of the OFET, such as field-effect mobility and bias-stress stability. Our synthesis and manufacturing method can be a useful technique for ensuring device operation stability and electrical property enhancement. With this analysis, we further applied our polymer-dielectric OFETs to flexible-platform-based electronic components, including unit OFETs and simple logic devices (NOT, NAND, and NOR gates). The outcomes of this research and development suggest a suitable method for the low-cost mass production of large-area flexible and printable devices, using a printing-based approach to replace current processes.

Herein, we fabricate highly deformable micro-supercapacitors (MSCs) based on gallium indium liquid metal (EGaIn) current collectors with integrated graphene. The well-defined interdigitated electrode patterning with controlled gap was successfully realized by using laser ablation technique due to strong laser absorption of graphene and EGaIn. By carefully controlling the gap size between adjacent interdigitated electrodes and the mass loading of graphene, we achieved high areal capacitance (1336 µF/cm2) with reliable rate performance. In addition, due to the intrinsic liquid properties of the EGaIn current collector, the energy storage performance of the MSC maintained 90% of its original areal capacitance even after repeated folding and 20% stretching (1000 cycles). Finally, we successfully integrated the deformable MSC with a commercial light-emitting diode to demonstrate the feasibility of MSC as a deformable power source. The fabricated MSCs operated stably under various mechanical deformations, including stretching, folding, twisting, and wrinkling.

Herein, we present a facile method to fabricate transparent, flexible, and high-performance thin-film heaters (TTFHs) based on nanostructured micromesh (NSMM) Cu-Ag/indium tin oxide bilayer transparent thin-film electrodes (TTFEs) with both nano- and microstructures. Our approach combines Ar-assisted thermal evaporation and pulsed laser ablation techniques to fabricate NSMM TTFEs with a low sheet resistance (-2.1 omega/sq) and high optical transmittance (-80.1 %). By adjusting the spacing of microholes, we can achieve excellent figure of merit values (-51.8 x 10-3 omega- 1) for the NSMM TTFEs. These electrodes also show excellent durability and flexibility, as evidenced by a resistance change of only 4 %-18 % in cyclic bending tests with up to 200,000 cycles. Finally, we demonstrate that the NSMM TTFEs can be used as high-performance TTFHs with short response times (3.97 s at a steady temperature of 87.5 degrees C under low-voltage operation (5 V)) and infrared shielding properties. Our results suggest that the Cu-Ag-alloy-based NSMM TTFEs are promising transparent electrodes for various applications in flexible electronics, smart windows, and wearable devices.

The field of printed electronics for highly integrated circuits and energy devices demands very fine and highly conductive electric interconnections. In this study, conductive lines having a high cross-sectional aspect ratio were printed via the inkjet printing of Ag nanoparticle inks assisted by a laser-induced selective surface wetting technique: a hydrophobic layer of self-assembled monolayer-treated ZnO nanorods was coated on a glass substrate and selectively ablated by a laser to form micro-channels for the inkjet, whose surface energy changed from 36.3 mJ/m2 to 51.5 mJ/m2 before and after the laser irradiation. With the varying width of the laser-ablated channels and pitch of jetted ink drops, the 3D shapes of the printed silver lines were measured to investigate their effects on the widths, heights, and uniformities of the printed patterns. The results showed that the present technique realized a uniform line of 35 μm width and 0.46 μm average thickness, having an aspect ratio of 0.013, which is 7.6 times higher than that printed on bare glass.

In this paper, a dual-band antenna-in-package front-end module for 5G mmWave mobile device applications is presented. A stacked dual-band dual-polarized broadband patch antenna loaded with parasitic patches were designed as a unit cell for antenna array. A proposed antenna module is composed of 1×5 patch antenna array and RFICs. The designed RFIC-integrated AiP module has measured EIRP value of 29.9 dBm at 28 GHz and 30.1 dBm at 29 GHz. It also has $+/-45^{\circ}$ beam-steering angle in both V- and H-pols. The designed mmWave module for 5G mmWave band has compact size of 26×5.2×2.1 mm 3 which is small enough to mount sides of most of commercial mobile devices.

Eutectic gallium–indium (EGaIn) is an ideal material for preparing flexible electrodes, but its high surface tension poses a challenge during deposition and patterning. Herein, we propose a laser-induced selective surface wetting technique (SSWT) to enable the facile and straightforward fabrication of flexible finely and directly patternable EGaIn liquid metal electrodes. Our proposed technique selectively controls the wettability of EGaIn by establishing a perfluorinated self-assembled monolayer on a zinc oxide nanorod array to impart superhydrophobicity and then inducing specific sites on the hydrophilized surface by ultraviolet (UV) pulsed laser ablation, thereby enabling fine patterning (linewidth, ~50 μm). Surface analysis of the effect of laser ablation was also performed to elucidate the mechanism of SSWT. The patterned EGaIn liquid metal electrode fabricated by SSWT exhibited superior flexibility, with a resistance change (ΔR/R0) of only 18.6% compared with a Ag thin film electrode, which showed a dramatic increase in ΔR/R0 to nearly 500% after 50,000 folding cycles at a peak strain of 2.5%. The simple and easily implementable liquid metal patterning technique proposed in this study may potentially be applied in the field of wearable and stretchable electronics, which requires extreme flexibility.

Nanostructures for a piezoresistive pressure sensor should be considered in terms of the interdigitated contacts formed through face-to-face assembly of the two electrodes to improve pressure-detecting performances.

Organic charge-modulated field-effect transistors (OCMFETs) have garnered significant interest as sensing platforms for diverse applications that include biomaterials and chemical sensors owing to their distinct operational principles. This study aims to improve the understanding of driving mechanisms in OCMFETs and optimize their device performance by investigating the correlation between organic field-effect transistors (OFETs) and OCMFETs. By introducing self-assembled monolayers (SAMs) with different functional groups on the AlOx gate dielectric surface, we explored the impact of the surface characteristics on the electrical behavior of both devices. Our results indicate that the dipole moment of the dielectric surface is a critical control variable in the performance correlation between OFET and OCMFET devices, as it directly impacts the generation of the induced floating gate voltage through the control gate voltage. The insights obtained from this study contribute to the understanding of the factors affecting OCMFET performance and emphasize their potential as platforms for diverse sensing systems.

Although several studies have focused on the application of deep-learning techniques in manufacturing processes, the lack of relevant datasets remains a major challenge. Hence, this paper presents a meta-learning approach to resolve the few-shot regression problem encountered in manufacturing applications. The proposed approach is based on data augmentation using conventional regression models and optimization-based meta-learning. The resulting deep neural network can be employed to optimize the reactive-sputtering process used in the fabrication of thin, compounded films of titanium and nitride. The performance of the proposed meta-learning approach is compared to the conventional regression models, including support vector regression, Bayesian ridge regression, and Gaussian process regression, which exhibit state-of-the-art performance for regression over small data sample counts. The proposed meta-learning approach outperformed the baseline regression models when tested by varying the training sample counts from 5 to 40, resulting in a decrease in the root mean square error to 74.6% of that observed in the conventional models to predict the stoichiometric ratio of the film produced during the reactive sputtering process. This is remarkable because regression performed over a small number of data is usually considered unsuitable for deep-learning approaches. Therefore, this approach exhibits considerable potential for usage in different manufacturing applications because of its capability to handle a range of dataset sizes.