As the field of wireless communication systems grows, the functionality of devices also continues to grow. Emerging research into wireless communication systems, with operating frequencies ranging from tens to hundreds of gigahertz, is leading to the development of gigabit wireless local area networks and automotive collision avoidance, to name two. Common manufacturing methods for millimeter-wave (mm-wave) antennas include etching (photolithography) and screen printing, which suffer from the use of harsh chemicals, high manufacturing costs, and complex manufacturing processes. The development of mm-wave devices requires effort to improve the versatility and cost of manufacturing. Ink-jet printing is attracting attention as a technology that has these characteristics. Ink-jet printing technology is an additive manufacturing process method that is attracting attention in the industry due to its advantages as a straightforward process with low cost, excellent scalability, and environmental friendliness compared to general laminate-based manufacturing methods [1]. The advantages and disadvantages of ink-jet printing compared to other printing technologies are reviewed in Table 1.

In this study, we developed a highly sensitive and selective gas sensor utilizing an In2O3/MXene-based nano-composite, which operates effectively at room temperature under UV irradiation. The incorporation of UV light enhances gas adsorption and desorption kinetics, resulting in a rapid and reversible resistance change upon NO2 exposure. Unlike conventional metal oxide-based gas sensors that require high-temperature operation (typically above 200 degrees C), our sensor demonstrates excellent photo-activated gas sensing capabilities at room temperature, significantly reducing power consumption and enhancing practical applicability. As a flexible sensor, it maintains mechanical robustness even after being bent more than 2000 times in application, and ensures long-term stability against external stress for more than 30 days. It has also been shown to maintain high selectivity for NO2 even in the presence of common interfering gases such as NH3, CO, SO2, and ethanol, which are commonly encountered in industrial and urban environments, and has been proven to maintain excellent gas detection performance even under harsh conditions such as high humidity (70 % RH) and direct water exposure. Excellent gas response with linearity was observed in the 5-100 ppb NO2 range, and the limit of detection (LOD) was calculated to be 0.79 ppb, indicating ultra-sensitive detection performance suitable for real-world air quality monitoring.

Violet emission is a compelling area in display technology, with wide-bandgap materials featuring high exciton binding energies being preferred. However, the limited violet emission efficiency of lead halide perovskites constrains their application in violet lighting. Here, we present a wide-bandgap cerium (Ce)-based perovskite derivative, Cs3CeBr6, as a promising alternative. To overcome the challenges of synthesis complexity, we develop a simple, water-based synthesis method for Cs3CeBr6 powders. These materials exhibit dual violet emission peaks at 392 and 421 nm, corresponding to parity-allowed high-energy transitions in Ce3+, with a short excited-state lifetime of similar to 29 ns. Owing to the high exciton binding energy of similar to 180 meV, Cs3CeBr6 is implemented as the active layer in fully solution-processed violet LEDs, achieving pure violet luminance and an external quantum efficiency (EQE) of 0.44%. These results highlight the potential of solution-synthesized Cs3CeBr6 as an efficient material for violet lighting applications.

Graphene quantum dots (GQDs) are fluorescent materials highly suited for biomedical applications owing to their excellent biocompatibility and low cytotoxicity. However, the chemical substances used in recent GQDs syntheses, such as polycyclic aromatic hydrocarbons and some aromatic organics, are causing severe environmental pollution. For sustainable research, we report a method for synthesizing recycled nitrogen-doped GQDs using waste graphite anode scrap (WGAS) extracted from retired lithium-ion batteries. Interestingly, increasing the inner cylinder temperature in a Couette-Taylor flow reactor from 37 to 44 degrees C during graphene oxide (GO) synthesis enhanced oxygen adsorption by approximate to 3 %. This led to a approximate to 20 % increase in photoluminescence (PL) intensity in GQDs synthesized hydrothermally. This indicates that the increased oxygen adsorption in GO enhances the density of the resulting oxidized debris, leading to a greater number of GQDs per unit volume. Our approach demonstrates an eco-friendly route to produce blue-emitting N-GQDs with enhanced optical properties.

A topological crystalline insulator (TCI) constitutes a valid candidate for optoelectronic applications owing to its broad spectral absorption, ultrafast response, and excellent stability. Thus far, the upscaling of the synthetic approach for TCIs has not been accomplished. Here, we proposed the one-step upscaling of a 6 in. two-dimensional (2D) SnSe0.9Te0.1 TCI for highly robust broadband photodetection from visible to LWIR. The photoresponsivity and detectivity of the SnSe0.9Te0.1-based photodetector corresponded to 3.34 A W-1 and 3.1 × 1011 Jones for 532 nm, 11.17 A W-1 and 1.07 × 1012 Jones for 1064 nm, 0.01 A W-1 and 1.03 × 1010 Jones for 1550 nm, and 0.002 A W-1 and 5.36 × 108 Jones for 4000 nm, respectively. In addition, the evident photoresponse was perceived by the subtle thermal radiation of human fingers. We systematically evaluated the performance reliability and multienvironmental stability of the SnSe0.9Te0.1-based photodetector under various conditions, including prolonged air exposure, thermal stress, humidity, and water immersion. We proposed a topological electronic structure of SnSe0.9Te0.1 by the atomic substitution of Te into orthorhombic SnSe, permitting the rock-salt phase transition in a localized area, resulting in highly robust broadband photodetection.

In response to regulations on material specifications for commercial applications requiring specific optical properties, researchers have developed lead-free materials over the past decade as alternatives to lead-based halide perovskite materials. An in-depth investigation into material composition has revealed various trends in the emission mechanism, showcasing significant potential characterized by distinctive features. This paper explores the inorganic cesium copper halide (ICCH) materials characterized by self-trapped exciton (STE) derived from 0D and 1D isolated metal halide structures. Our optical analyses indicate a predominant role of STE in influencing the optical properties. Further, we investigated the non-stoichiometric growth mechanism and identified its association with Cu+-OLA (oleylamine). The fabricated transition-metal dichalcogenides (TMD)based photodetector demonstrated enhanced performance using the 1D structured CsCu2X3 composition under 365 nm irradiation, attributed to its reduced electron-localization properties.

Magnesium (Mg) based materials hold immense potential for various applications due to their lightweight and high strength-to-weight ratio. However, to fully harness the potential of Mg alloys, structured analytics are essential to gain valuable insights from centuries of accumulated knowledge. Efficient information extraction from the vast corpus of scientific literature is crucial for this purpose. In this work, we introduce MagBERT, a BERT-based language model specifically trained for Mg-based materials. Utilizing a dataset of approximately 370,000 abstracts focused on Mg and its alloys, MagBERT is designed to understand the intricate details and specialized terminology of this domain. Through rigorous evaluation, we demonstrate the effectiveness of MagBERT for information extraction using a fine-tuned named entity recognition (NER) model, named MagNER. This NER model can extract mechanical, microstructural, and processing properties related to Mg alloys. For instance, we have created an Mg alloy dataset that includes properties such as ductility, yield strength, and ultimate tensile strength (UTS), along with standard alloy names. The introduction of MagBERT is a novel advancement in the development of Mg-specific language models, marking a significant milestone in the discovery of Mg alloys and textual information extraction. By making the pre-trained weights of MagBERT publicly accessible, we aim to accelerate research and innovation in the field of Mg-based materials through efficient information extraction and knowledge discovery.

The development of a hierarchical structure of Co/Co4N@NC has been successfully achieved. The robust oxygen evolution reaction activity of Co/Co4N@NC is attributed to the modulation of the d-band center, which reconstruct Co2+ into Co3+.

Designing composite gate dielectrics tailored by incorporating inorganic perovskite nanofillers into a polymer matrix to develop flexible low-voltage transistors can be challenging because homogeneous dispersion of nanomaterials in the matrix is difficult to achieve; thus, degradation of the electrically insulating properties of nanocomposite layers is often observed. In this study, nanocomposite dielectrics are presented that consist of 2D Ba5Ta4O15 nanosheets (BTO NSs) for the first time. Perovskite BTO is introduced using the Langmuir-Blodgett method to construct a precise and pinhole-free interface for the homogeneous assembly of 2D nanosheets. Its high k value and ferroelectric properties, which arise from the perovskite structure, can be harnessed to achieve attractive polarization and remarkable electronic properties. The 2D BTO NSs can also be utilized as phase crystallization fillers to enhance the ferroelectric properties of polyvinylidene fluoride (PVDF). Additionally, the multilayer PVDF/perovskite nanosheet hybrid dielectric, which reaches an unprecedentedly high dielectric constant of 22.4, exhibits effective dielectric relaxation related to the interfacial induced ferroelectric polarization and decisive negative-capacitance response. Perovskite-nanosheet-derived negative-capacitance-based flexible devices are realized using a rational approach. The ferroelectric properties are enhanced by adopting flexible multilayer nanocomposites based on 2D Ba5Ta4O15 nanosheets with PVDF, leveraging the interfacial effect and increasing the contact area using 2D Ba5Ta4O15 nanosheets. This approach allows functional flexible devices with heterogeneously structured dielectrics to be fabricated by inducing a negative-capacitance effect. image

The advancement of highly active electrocatalysts holds significant importance in enhancing hydrogen production technology and fostering the growth of the hydrogen energy economy. Herein, we present a novel electrocatalyst, Cu -doped Co decorated Nitrogen -doped Ti3C2Tx MXene Nanosheets (Cu/Co.TiO2@N-Ti3C2Tx), synthesized through a multi -step process involving the growth of Cu/Co-ZIF rhombic dodecahedrons on exfoliated Ti3C2Tx MXene nanosheets, followed by heat treatment. The resulting electrocatalyst exhibited remarkable performance in hydrogen evolution, with a low overpotential of 78 mV at - 10 mA/cm2 in a 1.0 M KOH solution. Tafel slope analysis revealed rapid kinetic response (119 mV dec � 1), and the electrocatalyst demonstrated exceptional durability over a 24 -hour Chronopotential run. This outstanding performance can be attributed to the synergistic effects of N-Ti3C2Tx nanosheets, Cu/Co, and TiO2, providing excellent electronic conductivity and structural robustness. Overall, the Cu/Co.TiO2@N-Ti3C2Tx composite offers significant potential for advancing hydrogen production technology, contributing to carbon emission reduction and environmental protection.

Context. 3C 84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of very-long-baseline interferometry (VLBI) above the hitherto available maximum frequency of 86 GHz. Aims. Using ultrahigh resolution VLBI observations at the currently highest available frequency of 228 GHz, we aim to perform a direct detection of compact structures and understand the physical conditions in the compact region of 3C 84. Methods. We used Event Horizon Telescope (EHT) 228 GHz observations and, given the limited (u, v)-coverage, applied geometric model fitting to the data. Furthermore, we employed quasi-simultaneously observed, ancillary multi-frequency VLBI data for the source in order to carry out a comprehensive analysis of the core structure. Results. We report the detection of a highly ordered, strong magnetic field around the central, supermassive black hole of 3C 84. The brightness temperature analysis suggests that the system is in equipartition. We also determined a turnover frequency of νm = (113 ± 4) GHz, a corresponding synchrotron self-absorbed magnetic field of BSSA = (2.9 ± 1.6) G, and an equipartition magnetic field of Beq = (5.2 ± 0.6) G. Three components are resolved with the highest fractional polarisation detected for this object (mnet = (17.0 ± 3.9)%). The positions of the components are compatible with those seen in low-frequency VLBI observations since 2017–2018. We report a steeply negative slope of the spectrum at 228 GHz. We used these findings to test existing models of jet formation, propagation, and Faraday rotation in 3C 84. Conclusions. The findings of our investigation into different flow geometries and black hole spins support an advection-dominated accretion flow in a magnetically arrested state around a rapidly rotating supermassive black hole as a model of the jet-launching system in the core of 3C 84. However, systematic uncertainties due to the limited (u, v)-coverage, however, cannot be ignored. Our upcoming work using new EHT data, which offer full imaging capabilities, will shed more light on the compact region of 3C 84.

One of the essential components for fabricating high-power-driven light-emitting diodes (LEDs) is phosphor in glass (PiG). Mixing, sintering, and polishing are necessary for this PiG fabricating technique for the blue LED to function as a light converter. However, oxidation of the phosphor during the sintering process result in degradation, and the yield lowers during the polishing stage. Here we suggest a laser sintering method to fabricate the PiG that has the advantages of a shorter process time and an increased yield. The quick processing time may inhibit the phosphor oxidations, and the Si wafer effectively inhibits bending during the laser sintering. Utilizing silicon wafers is the key to making the process practically usable. Testing on blue LED chips with 250 mA operating currents demonstrates sufficient performance for a PiG photoconverter fabricated using this laser sintering approach. The suggested technique can contribute to the development of the PiG industry due to its high efficiency.

This study presents a transfer learning approach for discovering potential Mg-based superconductors utilizing a comprehensive target dataset. Initially, a large source dataset (Bandgap dataset) comprising approximately ∼75k compounds is utilized for pretraining, followed by finetuning with a smaller Critical Temperature (Tc) dataset containing ∼300 compounds. Comparatively, there is a significant improvement in the performance of the transfer learning model over the traditional deep learning (DL) model in predicting Tc. Subsequently, the transfer learning model is applied to predict the properties of approximately 150k compounds. Predictions are validated computationally using density functional theory (DFT) calculations based on lattice dynamics-related theory. Moreover, to demonstrate the extended predictive capability of the transfer learning model for new materials, a pool of virtual compounds derived from prototype crystal structures from the Materials Project (MP) database is generated. Tc predictions are obtained for ∼3600 virtual compounds, which underwent screening for electroneutrality and thermodynamic stability. An Extra Trees-based model is trained to utilize Ehull values to obtain thermodynamically stable materials, employing a dataset containing Ehull values for approximately 150k materials for training. Materials with Ehull values exceeding 5 meV/atom were filtered out, resulting in a refined list of potential Mg-based superconductors. This study showcases the effectiveness of transfer learning in predicting superconducting properties and highlights its potential for accelerating the discovery of Mg-based materials in the field of superconductivity.

Research on manganese (Mn) halide perovskite derivatives with tunable emissions and high color purity have gathered a significant amount of attention for display technology. Despite of mesmerizing optical properties, the synthesis of these all-inorganic Mn halide compounds is followed by complex and toxic processes. Second, a precise control over the synthesis parameters is mandatory to achieve their pure emissions. Therefore, an ecologically sustainable water-based solution approach is adapted here to tailor the phases and emissions of cesium manganese bromide (Cs-Mn-Br) perovskite derivatives. It is observed that a controlled injection of solution stabilizer plays a pivotal role in engineering the intrinsic properties of Mn halide perovskites. This solution stabilizer interacts with the Mn-ions of those perovskite derivatives influencing their surrounding coordination environment and pure emission from then. A pure green emission with PLQY of 82% is achieved from as prepared Cs3MnBr5, whereas CsMnBr3 showed a red emission with PLQY of approximate to 20%. Encouraged by these properties phosphor-driven light emitting diodes (LED) are designed that show a steady electroluminescence intensity. The CIE coordinates of the Cs3MnBr5 and CsMnBr3 LED prototypes are at (0.224, 0.659) and (0.688, 0.316). This study showcases simple, eco-friendly tactics for developing green and red LED prototypes contributing toward sustainable device design.

AbstractHerein, we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs, where Co4N nanoparticles are encapsulated by Fe embedded in N‐doped carbon nanocubes to synthesize hierarchically structured Co4N@Fe/N–C for rechargeable zinc–air batteries and overall water‐splitting electrolyzers. As confirmed by theoretical and experimental results, the high intrinsic oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction activities of Co4N@Fe/N–C were attributed to the formation of the heterointerface and the modulated local electronic structure. Moreover, Co4N@Fe/N–C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure, uniform distribution of Co4N, and conductive encapsulation by Fe/N–C. Thus, the rechargeable zinc–air battery with Co4N@Fe/N–C delivers a high specific capacity of 789.9 mAh g−1 and stable voltage profiles over 500 cycles. Furthermore, the overall water electrolyzer with Co4N@Fe/N–C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts, delivering a high Faradaic efficiency of 96.4%. Along with the great potential of the integrated water electrolyzer powered by a zinc–air battery for practical applications, therefore, the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

Although the structural and electrical engineering of transition metal dichalcogenides using atomic doping or doping-induced phase modulation can be used to attain high-performance and wavelength-tunable optoelectronic devices, accessible substitutional doping to overcome the large lattice mismatch between the host and guest atom-related bonding states remains elusive. This study corroborates an innovative synthetic route for molybdenum disulfide (MoS2)-derived two-dimensional (2D) quaternary semiconductors substitutionally doped with Re and O using a solution-based large-area compatible approach combined with the thermal evaporation of dopants. The substitutional doping of Re into MoS2 crystals with a large lattice mismatch is effectively accomplished by adopting structurally unstable host films, resulting in the large-scale synthesis of 2D quaternary multi-layers with a Re doping concentration >10%. Comprehensive spectroscopic and microscopic evaluations are performed to determine the efficacy of the host films with structural instability for the synthesis of 2D RexMo(1-x)O2yS2(1-y) quaternary multi-layers. The capability of the quaternary semiconductor for versatile nanophotonic devices is validated by ascertaining the simultaneous enhancement of the photoelectrical properties with wide-range optical absorption and photoelectrochemical properties, as compared with those of their binary counterparts.

The advancement of digital technology has spurred the proliferation of data, creating a pressing need for efficient storage solutions. In this regard, memristors have emerged as promising contenders as next-generation non-volatile memory, offering superior electrical capabilities. Among memristor materials, lead halide perovskites have garnered significant interest due to their tuneable properties, facile synthesis methods, and remarkable resistive switching (RS) performance. However, concerns over environmental toxicity and stability remain. This issue has been addressed by switching to copper (Cu) based perovskites that exhibit wide bandgap semiconducting properties with zero toxicity and long-term stability. In this manuscript, a novel approach is investigated to achieve iodine-enriched Cs-Cu-I perovskite thin films for memristor applications. Through strategic functionalization of synthesis processes, superior optoelectronic properties are achieved in the thin films. This modified Cs-Cu-I based memristor (CCI device) exhibits excellent RS behavior at a low operating voltage of 0.7 V, with a long retention period of 4 x 103 s and very low power consumption of 2 x 10-9 W. The experimental realization of the synaptic behavior from the modified CCI device is demonstrated through its spike-rate-dependent plasticity (SRDP) behavior. The device response to short- and long-term pulses experimentally verifies the Atkinson and Shiffrin psychological model for training the human brain. This work not only highlights the potential of the modified CCI devices for RRAM but also paves the way for improved lead-free perovskite-based neuromorphic devices for biological applications. Memristors are promising for next-gen non-volatile memory, with lead halide perovskites leading the way. However, due to toxicity concerns, copper-based perovskites offer a safer alternative. A novel approach is adopted here to achieve iodine-rich Cs-Cu-I perovskite thin film that exhibits excellent resistive switching at low voltage and power, showing potential for lead-free, neuromorphic memory applications. image

Combining an electrochemically stable material onto the surface of a catalyst can improve the durability of a transition metal catalyst, and enable the catalyst to operate stably at high current density. Herein, the contribution of the N-doped carbon shell (NCS) to the electrochemical properties is evaluated by comparing the characteristics of the Ni3Fe@NCS catalyst with the N-doped carbon shell, and the Ni3Fe catalyst. The synthesized Ni3Fe@NCS catalyst has a distinct overpotential difference from the Ni3Fe catalyst (eta(OER) = 468.8 mV, eta(HER) = 462.2 mV) at (200 and -200) mA cm(-2) in 1 m KOH. In stability test at (10 and -10) mA cm(-2), the Ni3Fe@NCS catalyst showed a stability of (95.47 and 99.6)%, while the Ni3Fe catalyst showed a stability of (72.4 and 95.9)%, respectively. In addition, the in situ X-ray Absorption Near Edge Spectroscopy (XANES) results show that redox reaction appeared in the Ni3Fe catalyst by applying voltages of (1.7 and -0.48) V. The decomposition of nickel and iron due to the redox reaction is detected as a high ppm concentration in the Ni3Fe catalyst through Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis. This work presents the strategy and design of a next-generation electrochemical catalyst to improve the electrocatalytic properties and stability.

AbstractReducing transmission loss via composites with pores has emerged as a breakthrough method for information and communications technology applications. The super/extremely high‐frequency signals used in the technologies result in significant transmission loss. Demand for low‐loss materials with low dielectric constant (Dk) and low dissipation factor (Df) has increased in recent years. Here, it is demonstrated that the pore in composites can be reduced Dkand Dfof composites with pores (air). In fabrication of composites, a drop‐on‐demand (DOD) inkjet printing method to fabricate composites with pores (air) for use in wireless communications technologies. The DOD method is a simple but versatile manufacturing process at low cost. Its versatile process makes it possible to control the amount of resin and pore in fabrication of the composites and moreover to distribute all their components isotopically and homogeneously. It is possible to fabricate the composites with a lower Dkand Dfvalue by increasing pore amount in the composites. This strategy enabled us to inexpensively manufacture dielectric substrates with low Dkand Dfvalues, greatly contributing to the communications technology industry.