Metallic Conductivity Research Articles

Flexible Electronic Patch Utilizing Gelatin Film for Heart and Brain Signal Detection.

Flexible electronic patches have been widely studied in various fields. However, they still face serious challenges in cardio-brain signaling monitoring to achieve accurate adhesion and detection with compatibility in mildly humid environments. To tackle these challenges, we engineered a gelatin hydrogel film cross-linked with a biocompatible matrix factor and combined it with a blend of liquid metal and PVP to create the flexible electronic patch. The flexible patch has good biocompatibility and fatigue resistance due to the incorporation of liquid metal and natural gelatin, with the conductivity of liquid metal and minimal toxicity of the gelatin film. It is possible to securely insert it into the body for a duration of 3 weeks while maintaining monitoring functionality and withstanding 10 000 cycles of flexural fatigue. This research provides an innovative approach to the future advancement of flexible electronic patches.

Explore the physical properties of the synthesized UiO-66, Zn-BiOBr, and Zn-BiOBr/UiO-66 heterostructures for optical applications

The Zn-BiOBr/UiO-66 Heterostructures were prepared using a simple wet chemical method. Three heterostructures were prepared by varying the weight percentage of UiO-66 to Zn-BiOBr. The prepared materials' chemical compositions and phase structure were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, the morphology was investigated via Field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX), and elemental mapping techniques. The optical features were analyzed through UV–vis spectrophotometry. The bandgap energy was calculated using the Tauc equation and was found 4.24eV for UiO66 and 2.17eV for the ZnBiOBr composite. After combining the ZnBiOBr composite with the UiO66 material the bandgap energy of the composite decreased to 4.07, 3.94, and 3.75eV after doping 10, 20, and 30% UiO-66, respectively. Additionally, the refractive index of the Zn-BiOBr/UiO-66 heterostructure increases from 2.1520 for the UiO-66 composite to about 2.1929, 2.2254, and 2.2748 for 10, 20, and 30% UiO66. Moreover, an enhancement was observed for other optical parameters like electronegativity, metallization, and optical conductivity. Besides, the W-DD model was used to investigate the nonlinear optical parameters, which showed an improvement in the first- and third-order nonlinear optical susceptibility, and nonlinear refractive index values with increasing UiO-66 content in the composite matrix.

BA-ATEMNet: Bayesian Learning and Multi-Head Self-Attention for Theoretical Denoising of Airborne Transient Electromagnetic Signals.

Airborne transient electromagnetic (ATEM) surveys provide a fast, flexible approach for identifying conductive metal deposits across a variety of intricate terrains. Nonetheless, the secondary electromagnetic response signals captured by ATEM systems frequently suffer from numerous noise interferences, which impede effective data processing and interpretation. Traditional denoising methods often fall short in addressing these complex noise backgrounds, leading to less-than-optimal signal extraction. To tackle this issue, a deep learning-based denoising network, called BA-ATEMNet, is introduced, using Bayesian learning alongside a multi-head self-attention mechanism to effectively denoise ATEM signals. The incorporation of a multi-head self-attention mechanism significantly enhances the feature extraction capabilities of the convolutional neural network, allowing for improved differentiation between signal and noise. Moreover, the combination of Bayesian learning with a weighted integration of prior knowledge and SNR enhances the model's performance across varying noise levels, thereby increasing its adaptability to complex noise environments. Our experimental findings indicate that BA-ATEMNet surpasses other denoising models in both single and multiple noise conditions, achieving an average signal-to-noise ratio of 37.21 dB in multiple noise scenarios. This notable enhancement in SNR, compared to the next best model, which achieves an average SNR of 36.10 dB, holds substantial implications for ATEM-based mineral exploration and geological surveys.

Magnetointeractive Cr2Te3-Coated Liquid Metal Droplets for Flexible Memory Arrays and Wearable Sensors.

Magnetic liquid metal droplets, featured by unique fluidity, metallic conductivity, and magnetic reactivity, are of growing significance for next-generation flexible electronics. Conventional fabrication routes, which typically incorporate magnetic nanoparticles into liquid metals, otherwise encounter the pitfall pertaining to surface adhesivity and corrosivity over device modules. Here, an innovative approach of synergizing liquid metals with 2D magnetic materials is presented, accordingly creating chromium(III)-telluride-coated liquid metal (CT-LM) droplets via a simple self-assembly process. The CT-LM droplets exhibit controllable deformation and locomotion under magnetic fields, demonstrate nonadherence to various surfaces, and enable cost-effective recycling of components. The functionality of CT-LM droplets is validated through their use in magnetointeractive memory devices to enable sensing/storing 64 magnetic paths and in wearable sensors as the flexible vibrator for dynamic gesture recognition with machine learning assistance. This work opens new avenues for the functional droplet design and broadens the horizons of flexible electronics.

Bimetallic Conductive Metal Organic Framework Nanorods with Atomically Dispersed Fe and Co Sites for Efficient Oxygen Evolution

Bimetallic Conductive Metal Organic Framework Nanorods with Atomically Dispersed Fe and Co Sites for Efficient Oxygen Evolution

2D Vertically Conductive Metal─Organic Framework Electrolytes: Will They Outperform 3D MOFs for Solid State Batteries?

Lithium-ion batteries are currently the mainstream for almost all portables, and quickly expand in electrical vehicles and grid storage applications. However, they are challenged by the poor safety regarding organic liquid electrolytes and relatively low energy density. Solid-state batteries, characterized by using solid-state electrolytes (SSEs), are recognized as the next-generation energy technology, owing to their intrinsically high safety and potentially superior energy density. However, developing SSEs is impeded by several key factors, including low ionic conductivity, interfacial issues, and high-cost in industrial scales. Recently, a novel category of SSEs, known as frameworked electrolytes (FEs), has emerged as a formidable contender for the transition to all-solid-state batteries. FEs exhibit a unique macroscopically solid-state nature and microscopically sub-nanochannels offering high ionic conductivity. In this perspective, the unique lithium-ion transport mechanisms within FEs are explored and 2D vertically conductive metal-organic framework (MOF) is proposed as an even more promising FE candidate. The abundant active sites in the 1D sub-nanochannels of 2D vertically conductive MOFs facilitate efficient ion transport, favorable interfacial compatibility, and scalable industrial applications. This perspective aims to boost the emergence of novel SSEs, promoting the realization of long-expected all-solid-state batteries and inspiring future energy storage solutions.

Long‐Cycle Stable Zn2+ Storage in 2D Conductive Metal–Organic Frameworks via Exclusive Ligand Redox Mechanism

Abstract2D conductive metal–organic frameworks (2D c‐MOFs) have emerged as novel cathode materials in the development of rechargeable aqueous zinc‐ion batteries (ZIBs) because of its integrated multiple redox‐active moieties. However, the redox of the metal nodes usually leads to the collapse of the c‐MOF structure during Zn2+ insertion/extraction process, thereby curtailing its cycling lifespan. Herein, a triphenylene‐catecholate‐based 2D c‐MOF (Zn‐HHTP) is fabricated by chelating the inactive Zn nodes, endowing the structural stability during charge and discharge processes only through ligand redox. The 1D open channel of Zn‐HHTP facilitates rapid insertion and extraction of zinc ions, thus enabling stable working of ZIBs at high rates. Impressively, Zn‐HHTP as cathode in ZIBs exhibits an ultra‐long cycling stability with capacity retention of 86.6% after 4000 cycles at the current density of 4 A g−1, exceeding the other MOF‐based cathodes ever reported. Density functional theory (DFT) calculations combined with ex situ X‐ray photo‐electron spectroscopy (XPS) further elucidate the redox mechanism between catechol and benzene ring of HHTP during the successive insertion/extraction of Zn2+, due to their comparatively negative electrostatic potentials. This work provides a new strategy to prolong the cycling capability of ZIBs by utilizing the highly active non‐metallic redox moieties in 2D c‐MOFs.

A Review of Transparent Conducting Films (TCFs): Prospective ITO and AZO Deposition Methods and Applications.

This study offers a comprehensive summary of the current states as well as potential future directions of transparent conducting oxides (TCOs), particularly tin-doped indium oxide (ITO), the most readily accessible TCO on the market. Solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), antireflection (AR) coatings for airbus windows, photovoltaic and optoelectronic devices, transparent p-n junction diodes, etc. are a few of the best uses for this material. Other conductive metals that show a lot of promise as substitutes for traditional conductive materials include copper, zinc oxide, aluminum, silver, gold, and tin. These metals are also utilized in AR coatings. The optimal deposition techniques for creating ITO films under the current conditions have been determined to be DC (direct current) and RF (radio frequency) MS (magnetron sputtering) deposition, both with and without the introduction of Ar gas. When producing most types of AR coatings, it is necessary to obtain thicknesses of at least 100 nm and minimum resistivities on the order of 10-4 Ω cm. For AR coatings, issues related to less-conductive materials than ITO have been considered.

A Transparent and Robust Ionogel with Stress-Induced Microphase Separation Property and Crack Insensitivity for Visual Force Sensor.

Gel with ionic conductivity and stretchability is considered as an ideal alternative to conventional rigid metallic conductors in the flexible electronics. However, present gels suffer from poor mechanical properties and crack sensitivity due to their weak intermolecular (chain) interactions and homogeneous network structure. Herein, a transparent and tough polyacrylamide (PAM) ionogel is designed, which can form stress-induced microphase-separated domains with high hydrogen bonding density under stress to inhibit crack propagation. Benefiting from multiple hydrogen bonding interactions, the PAM ionogel exhibited maximum tensile stress of 5.19 ±0.52MPa, maximum tensile strain of 685.49 ±22.15%, and fracture toughness of 10.11 ±1.63kJm-2. On the other hand, the visual force sensor is realized by utilizing the stress-induced changes in the grayscale and electrical resistance of the PAM ionogel, which allowed real-time and visual monitoring of the stress applied to an object as a whole or in part. This work may open new avenues for the development of stable and reliable flexible sensors.

Charge transport mechanism in [GeOx](z)[SiO2](1-z) based MIS structures

The mechanisms of conductivity in metal–insulator–semiconductor (MIS) structures based on [GeOx](z)[SiO2](1-z) films (0.25 ≤ z ≤ 1) fabricated by co-evaporation of germanium oxide and silicon oxide powders in vacuum and deposition on a p+-type silicon substrate are studied. Indium tin oxide deposited by magnetron method is used as the top electrode. According to IR spectroscopy, Ge–O, Si–O, and Ge–O–Si bonds are detected in the films, while no features related to the presence of germanium clusters are found in the Raman spectra. The current–voltage characteristics (I–V curves) are measured at different temperatures and analyzed by applying the eight most common models of charge transport in MIS structures. It is found that the experimental I–V curves are most accurately approximated in the space charge limited current model, and the parameters of the charge traps are determined within this model.

Shot Noise in a Metal Close to the Mott Transition.

SrIrO3 is a metallic complex oxide with unusual electronic and magnetic properties believed to originate from electron correlations due to its proximity to the Mott metal-insulator transition. However, the nature of its electronic state and the mechanism of metallic conduction remain poorly understood. We demonstrate that the shot noise produced by nanoscale SrIrO3 junctions is strongly suppressed, inconsistent with diffusive quasiparticle transport. Analysis of thermal effects and scaling with the junction length reveals that conduction is mediated by collective hopping of electrons almost localized by correlations. Our results provide insight into the non-Fermi liquid state close to the Mott transition and advance shot noise measurements as a powerful technique for the study of quantum materials.

Spectral SPR effect in thin films of high-conductive metals and features of SPR-biosensors implementation in chromatic mode

In this paper, we have evaluated the application of various types of highly conductive metals for implementing the effect of spectral surface plasmon resonance (SPR) within a visible spectrum range to achieve more efficient and productive registration of biomolecules in a liquid medium using tricolor RGB cameras. Thin films of gold, silver, copper, and aluminum, as well as a bimetallic coating of silver with a gold superlayer on a glass substrate, are considered. Detailed calculations of the spectral characteristics of reflection at SPR excitation in the Kretschmann geometry are performed, particularly when a thin dielectric film is formed on the metal surface that imitates a layer of biomolecules. For each of the specified metals, the width of the region of implementation of the full-fledged SPR effect in the visible range of the spectrum is determined, and the sensitivity of the optical response to the influence of an external dielectric layer is assessed.

Conductive Metal–Organic Frameworks for Rechargeable LiOH-Based Li–O2 Batteries

Conductive Metal–Organic Frameworks for Rechargeable LiOH-Based Li–O₂ Batteries

Microenvironment modulation of Ni center in Pt@Ni-hexahydroxytriphenylene composites for bifunctional lithium-sulfur separators

In lithium-sulfur (Li-S) batteries, cycling capacities and stabilities are severely deteriorated by shuttle effects and Li dendrite growth. Herein, shuttle effects and Li dendrite growth are simultaneously suppressed by conductive metal organic framework (c-MOF) of Ni-2,3,6,7,10,11-hexahydroxytriphenylene (Ni-HHTP) functionalized with Pt nanoclusters (denoted as Pt@Ni-HHTP). The microenvironment of Ni in Ni-HHTP is modulated by Pt nanoclusters, which are proved by calculations and experimental results. Consequently, enhanced electrical conductivities and strong adsorption abilities toward lithium polysulfides (LiPSs) are realized with microenvironment modulations (MEM). Li+ diffusion is accelerated with Pt addition at the same time. Li-S batteries with Pt@Ni-HHTP separator realize improved capacity due to MEM. Moreover, a stable cycling is achieved under high S loading and limited electrolyte. This work applies references to regulate the electrochemical behaviour of active center by MEM, addressing the challenges on both electrodes in Li-S batteries.

Digital Shear Printing of Mechanically Robust Liquid Metal Circuits with Hierarchical Embedded Structure for Paper Electronics

The seamless integration of recyclable and deformable liquid metal (LM) conductors into paper is attractive to developing flexible, breathable, and green electronics. However, the weak adhesion between paper and LM complicates the patterning. In addition, the low damage endurance of LM, an open problem for on‐surface conductors, restricts the practical applications. Here, a simple yet efficient approach of shear printing is reported to directly pattern hierarchical embedded LM circuits with erasure resistance onto paper. This is achieved by digitally applying the shear force to the solid gallium film to induce its adhesive wear with the paper, allowing the gallium to be embedded into the paper's fiber networks. Meanwhile, the pressure‐induced formation of microgrooves on paper allows the LM circuits to be surface‐embedded onto paper. The hierarchical embedded structure endows the LM circuits with enhanced mechanical damage endurance that they can even withstand eraser rubbing and tape peeling. Applications of the hierarchical embedded, mechanically robust, and breathable LM‐enabled paper electronics in enhanced humidity sensing, electrophysiology monitoring, and digital droplet microfluidics are also shown. This work opens doors to developing sustainable yet robust paper electronics by rationally utilizing the solid properties of low‐melting‐point metals.

3D Soft Architectures for Stretchable Thermoelectric Wearables with Electrical Self-Healing and Damage Tolerance.

Flexible thermoelectric devices (TEDs) exhibit adaptability to curved surfaces, holding significant potential for small-scale power generation and thermal management. However, they often compromise stretchability, energy conversion, or robustness, thus limiting their applications. Here, the implementation of 3D soft architectures, multifunctional composites, self-healing liquid metal conductors, and rigid semiconductors is introduced to overcome these challenges. These TEDs are extremely stretchable, functioning at strain levels as high as 230%. Their unique design, verified through multiphysics simulations, results in a considerably high power density of 115.4µWcm⁻2 at a low-temperature gradient of 10°C. This is achieved through 3D printing multifunctional elastomers and examining the effects of three distinct thermal insulation infill ratios (0%, 12%, and 100%) on thermoelectric energy conversion and structural integrity. The engineered structure is lighter and effectively maintains the temperature gradient across the thermoelectric semiconductors, thereby resulting in higher output voltage and improved heating and cooling performance. Furthermore, these thermoelectric generators show remarkable damage tolerance, remaining fully functional even after multiple punctures and 2000 stretching cycles at 50% strain. When integrated with a 3D-printed heatsink, they can power wearable sensors, charge batteries, and illuminate LEDs by scavenging body heat at room temperature, demonstrating their application as self-sustainable electronics.

Two-Dimensional MXene-Based Functional Composites for Photocatalysts: Current Status and Perspectives

Abstract: MXenes, as novel two-dimensional (2D) transition metal carbides, nitrides or carbonitrides, have excellent metal conductivity, high carrier mobility, and surface-terminated groups regulated band structure. It can be thus used as a cocatalyst in photocatalytic systems to improve the photocatalytic properties. This review represented recent research progress on the controllable construction of MXene-based functional composites with zero-dimensional (0D), one-dimensional (1D), 2D, and three-dimensional (3D) semiconductor photocatalysts and their applications for photocatalysts. Extensive information related to 2D MXene-Based composites for photocatalysts and their associated patents were collected. The construction methods and photocatalytic enhancement mechanisms of 2D MXene-based composite photocatalysts were given. Due to their excellent physical and chemical properties, 2D MXene composites have been widely used in pollutant removal, hydrogen production, CO2 reduction, and nitrogen fixation. Through the construction of 2D MXene-based functional composite photocatalysts with novel structures and excellent performance, it provides a new perspective for the design and construction of high-efficiency photocatalysts. The future research directions of MXene-based composite photocatalysts was proposed.

Mineralogical characterization of the Seffner fulgurite, Florida: Insights into lightning-induced petrogenesis

Abstract Fulgurites are glasses formed when electrical discharge hits a target material made of soil, sand, or rock. Due to their formation conditions, fulgurites inform how high-temperature processes and rapid quenching of rocks results in peculiar mineralogical assemblages characterized by the presence of reduced phases. Fulgurites can either be natural, or artificial, with the latter occurring when the electrical discharge is not due to lighting but to a downed power line, and anthropogenic if the target material is not completely natural, allowing for a wide range of temperatures and materials involved in their formation. Artificial and anthropogenic fulgurite are far less characterized than natural ones. In this work, we studied a fulgurite from Seffner, Florida, U.S.A., formed by the action of a downed power line. The fulgurite also contains a piece of a metal conductor, thus providing the interesting opportunity to characterize the interface between the metal and the silicatic portion of the sample. The Seffner fulgurite contains a huge variety of reduced phases, comprising metallic silicon, iron silicide, Al-Fe-Si and Fe-Si-Ti compounds. The iron silicides point to an environment rich in silicon and exposed to relatively low temperatures, as typical in artificial fulgurites. Al-containing phases are found close to the metal conductor, suggesting that Al metal in the wire could play a major role in determining the mineralogy of the Seffner fulgurite and in driving the formation of reduced phases. Conversely, Fe-Si-Ti phases occur in the whole fulgurite fragment containing the metal conductor, suggesting the action of another source of reduction, most probably organic carbon. Noteably, analysis of other portion of the fulgurite samples far from the metal conductor shows a minor presence of reduced phases, supporting the role of Al as a fundamental driver of the reduction.

Recent Advancements in Co3O4-Based Composites for Enhanced Electrocatalytic Water Splitting.

The pursuit of efficient and economical catalysts for water splitting, a critical step in hydrogen production, has gained momentum with the increasing demand for sustainable energy. Among the various electrocatalysts developed to date, cobalt oxide (Co3O4) has emerged as a promising candidate owing to its availability, stability, and catalytic activity. However, intrinsic limitations, including low catalytic activity and poor electrical conductivity, often hinder its effectiveness in electrocatalytic water splitting. To overcome these challenges, substantial efforts have focused on enhancing the electrocatalytic performance of Co3O4 by synthesizing composites with conductive materials, transition metals, carbon-based nanomaterials, and metal-organic frameworks. This review explores the recent advancements in Co3O4-based composites for the oxygen evolution reaction and the hydrogen evolution reaction, emphasizing strategies such as nanostructuring, doping, hybridization, and surface modification to improve catalytic performance. Additionally, it examines the mechanisms driving the enhanced activity and stability of these composites while also discussing the future potential of Co3O4-based electrocatalysts for large-scale water-splitting applications.

Metallic bilayer Kagome borophene as a promising anode material for Li and post-Li ion batteries

For future breakthroughs in alkali metal ion batteries, it is essential to explore new anode materials with high storage capacity. Recently, a novel two-dimensional material, bilayer Kagome borophene (BK-borophene), consisting of lightweight elemental boron and having excellent metal conductivity, has been proposed. Thus, the structure, stability, electronic and electrochemical properties of BK-borophene are investigated using first-principles calculations to examine its feasibility as an anode material. Our results show that a single Li/Na/K can stably adsorb on the BK-borophene surface with adsorption energy values of −0.46/-0.25/-0.69 eV. Besides, the low diffusion barrier values (0.55/0.30/0.15 eV) ensure that Li/Na/K can migrate rapidly on its surface, and the low open circuit voltage values are favorable for increasing the operating voltage of the assembled battery. Most importantly, BK-borophene shows high theoretical storage capacities of 826 mA h g−1 for Li, 1377 mA h g−1 for Na, and 275 mA h g−1 for K, which is much more favorable than other reported anode materials. Not only that, BK-borophene also exhibits good cycling stability. The above-mentioned findings suggest that BK-borophene can be a promising and convincing anode material for alkali metal ion batteries.