Dielectric Electrode Research Articles

High electroresistance in all-oxide ferroelectric tunnel junctions enabled by a narrow bandgap Mott insulator electrode

Ferroelectric tunnel junctions (FTJs) based on epitaxial complex oxide heterostructures are promising building blocks for developing low power nanoelectronics and neuromorphic computing. FTJs consisting of correlated oxide electrodes have distinct advantages in size scaling but only yield moderate electroresistance (ER) at room temperature due to the challenge in imposing asymmetric interfacial screening and large modulation of the tunneling potential profile. Here, we achieve large ER in all-oxide FTJs by paring a correlated metal with a narrow bandgap Mott insulator as electrodes. We fabricate epitaxial FTJs composed of 2.8 and 4 nm PbZr0.2Ti0.8O3 tunnel barriers sandwiched between correlated oxides LaNiO3 and Sr3Ir2O7 electrodes. An ER of 6500% has been observed at room temperature, which increases to over 105% at 100 K. The high ER can be attributed to ferroelectric polarization induced metal–insulator transition in interfacial Sr3Ir2O7, which enhances the potential asymmetry for the tunnel barrier. The temperature dependence of tunneling current shows that direct tunneling dominates in the on state, while the off-state conduction transitions from thermally activated behavior at high temperatures to Glazman–Matveev defect-mediated inelastic tunneling at low temperatures. Our study provides a viable material strategy for designing all-oxide FTJs with high ER, facilitating their implementation in nonvolatile memories and energy-efficient computing devices.

Investigation on the Regulation of the Combustion Characteristics of a Propane/Air Mixture by Repetitive nSDBD Pretreatment.

This paper investigates the effect of the transient repetitive nanosecond surface dielectric barrier discharge (nSDBD) pretreatment on the combustion characteristics of combustible mixtures. A method of using nSDBD online pretreatment of a combustible mixture to regulate the combustion characteristics of the mixture is proposed. The study is conducted in a constant-volume combustion chamber at atmospheric pressure and temperature using a propane/air mixture as fuel. The discharge characteristics of repetitive nSDBD and the effects of pretreatment discharge energy and interval time between the pretreatment and ignition on combustion rate are discussed. The results show that (1) For 12.5 kHz pulses, the filament length generated with the annular dielectric barrier electrode discharge can reach up to 7 mm, and the number of discharge filaments per pulse can reach 40. (2) Pretreating mixtures using repetitive nSDBD at millisecond time scale can significantly improve the combustion process. (3) Repetitive nSDBD pretreatment can enhance the activity of the mixture near the surface of nSDBD electrode, which leads to obvious wrinkles on the flame surface and significantly improves the combustion rate. (4) The flame rise time decreases with the increase of discharge energy and increases with the increase of the interval time between the pretreatment and ignition. The effect of the repetitive nSDBD pretreatment on flame propagation during the flame development period becomes more pronounced with the increase of the excess air coefficient. The research results of the paper reveal the law of online regulation of combustion characteristics of combustible mixtures by the nSDBD, providing experimental data support for the mechanism research of online regulation of combustion characteristics of combustible mixtures by the nSDBD.

Parameter characterization of variable bending stiffness module with electrostatic layer jamming based on giant electrorheological fluid

Soft grippers exhibit good adaptability, but their grasping performance is limited. Variable-stiffness technology has been applied to soft grippers to address this problem. Therefore, a variable bending stiffness module (VBSM) with electrostatic layer jamming based on a giant electrorheological fluid (ELJ-GERF) for soft robots is proposed in this study, which exhibits a faster response time and a wider range of stiffness variation. A VBSM prototype is fabricated, and a theoretical model is established. The stiffness is mainly affected by the electrode quantity, overlapping area of electrode plates, insulator and conductive layers’ thickness, medium thickness and the exciting voltage. Direct current (DC) voltage experiments and alternating current (AC) voltage experiments were conducted on the test samples of filled with air (ELJ-AIR), silicone oil (ELJ-OIL), and ELJ-GERF. The experimental result show that stiffness-regulation of the VBSM can be achieved by adjusting the exciting voltage, and AC voltage being more suitable for regulating the stiffness of the VBSM than DC voltage. For AC voltage, the stiffness of ELJ-GERF increases to 53.5 times when a 4 kV voltage is applied. The stiffness variation range is about 2 to 3 times greater than that of ELJ-AIR or ELJ-OIL. Through the stiffness characterization experiment, the stiffness of the VBSM in this study is influenced by the viscosity of the GERF and the gap between the electrode plates. Through the capacitance test, the VBSM exhibits self-sensing ability. Finally, the VBSM is applied to a soft gripper, the vibration performance and variable stiffness performance in its application are verified.

Self-isolating electrode deposition process using the area-selective MoO2 and MoO3 atomic layer deposition technique

The traditional patterning process for semiconductor devices typically involves multiple steps, including thin film deposition across the entire substrate, selective removal of unwanted regions through lithography and etching, and subsequent isolation. While area-selective deposition process has been employed to eliminate the need for lithography and etching, the isolation step remains essential. In this study, we suggest an innovative approach to achieve “self-isolation electrode formation” using MoO2 and MoO3 as electrode and inter-metallic insulator materials. In a single deposition batch and subsequent post-deposition annealing (PDA) process, deposited MoOx (x: 2∼3) thin films exhibited transformation into highly crystalline MoO2 and MoO3 with low crystallinity, depending on whether they were deposited on TiN or SiO2 surfaces. We conducted comprehensive analyses, including chemical and electrical characterizations, as well as first-principles calculations based on density-functional theory, to elucidate the underlying mechanisms responsible for the differential reduction and crystallization of MoOx thin films. Finally, we successfully demonstrated the formation of self-isolation electrodes within a vertical structure, accomplished through a single-step process involving MoOx deposition and subsequent PDA. This novel approach, built upon advanced area-selective deposition techniques, holds great promise for the development of state-of-the-art semiconductor devices.

Electrical discharge drilling of blind holes with injection flushing dielectric and stepped electrodes

Electrical discharge drilling of blind holes has been a challenging task due to the inherent difficulties in removing debris from the discharging gap. This paper investigates the working mechanism and effects of new stepped electrodes which are used in conjunction with injection flushing in drilling deep blind holes. A series of theoretical simulations and comparative experiments were conducted using cylindrical electrodes and two types of stepped electrodes. Pulse waveforms were captured to analyse the discharge status. Surface topography and machining quality were analysed using scanning electron microscope (SEM) images. The machining performance was evaluated by studying the material removal rate (MRR) and tool wear ratio (TWR). Experiment results show that internal flushing caused the debris to circulate in the machining zone and led to abnormal discharges, disrupting the formation of the plasma channel. The MRR was increased by 75% and 82% when using cylindrical electrodes with pressures of 120 psi and 40 psi, respectively. In contrast, the MRR with injection flushing was about 80% of that without injection flushing when using stepped electrodes. Regardless of the type of electrode, the application of injection flushing resulted in the increase in the maximum effective machining depth.

Simple Solution Processed Solid‐State Organic Transistor Chip for Multi‐Ion Sensing

AbstractIon concentrations in the human body are closely tied to crucial biological functions and thus serve as important diagnostic health markers. Biological samples are chemically complex, containing a wide range of ions and molecules, necessitating the use of sensors that are highly selective to the target analyte. In this work, a multi‐ion sensing chip, capable of selectively detecting potassium (K+), sodium (Na+), and calcium (Ca2+) ions at physiologically relevant concentrations, is demonstrated. Each sensor consists of a simple, solution‐processed, all solid‐state, and low‐voltage organic thin film transistor, functionalized with polyvinyl chloride (PVC) ion selective membranes sandwiched between the insulator and gate electrode. The sensors are responsive to 4–5 decades of each primary ion. When a response from interfering ions is seen at higher concentrations, the sensors can uniquely discriminate between primary and interfering ions by a difference in the polarity of the current modulation. The sensors function well in mixed‐ion solutions, and can detect K+, Na+, and Ca2+ in simulated human blood serum, demonstrating the feasibility of using these devices for the analysis of complex analytes. This work represents an important step toward the development of simple, inexpensive organic multi‐ion sensors.

Flexible capacitive pressure sensor with synergistic effect between double-sided pyramid sponge structure dielectric layer and fiber structure electrode layer

Flexible capacitive pressure sensors have a wide range of applications in wearable applications. This paper prepares a double-sided pyramidal foam sponge doped with barium titanate particles as the sensor dielectric layer by template method, and the flexible electrode layer prepared by electrostatic spinning technique. Benefiting from the excellent compressibility of the dielectric layer under stress and the good deformability of the electrode layer, the sensors with a synergistic effect between the electrode layer and the dielectric layer have been assembled. The sensor has high sensitivity (0.44 kPa−1) and a wide range (0–300 kPa), fast response (90 ms), ultra-low detection limit of 0.01 kPa, and reliable durability (>2000 cycles). The excellent performance of the sensor can realize the detection of human body signals and assembled into a data glove and combined with a host monitor to enable real-time monitoring of signal changes during grasping, and it shows enormous potential in intelligent wearable device applications.

Investigations on the optical, dielectric, electrical, and rheological properties of PEG200/ZnO semiconducting nanofluids for soft matter based technological innovations

Semiconducting nanofluids (SNFs) consisting of poly (ethylene glycol) (PEG200) as a green biocompatible base fluid with homogeneous dispersion of eco-friendly zinc oxide (ZnO) nanomaterial, concentrations ranging from 0.01 to 0.20 wt%, are prepared by state-of-the-art ultrasonic cavitation homogenized process. These PEG200/ZnO SNFs are characterized by employing an ultraviolet-visible (UV-Vis) spectrophotometer, precision inductance-capacitance-resistance (LCR) meter, and rotational viscometer. A detailed analysis of 200–800 nm range UV–Vis absorbance spectra of these SNFs revealed longer stability of suspended ZnO nanoparticles in PEG200 fluid, and their nanomaterial concentrations dependent absorbance and extinction coefficient with tunable dual energy band gaps ranging from 3 to 5 eV. Optical performance recognized the potential applications of these SNFs in the advances of soft matter based optoelectronic and photosensitive devices and also as an excellent UV radiation shielding material. The study of 20 Hz – 1 MHz range dielectric and electrical spectra explained that the ZnO concentrations have a significant impact on the electrical conductivity of these SNFs, while the dielectric permittivity and electrode polarization relaxation process are marginally altered. High static dielectric permittivity (∼ 22) and low electrical conductivity of about μS/cm order, at 303.15 K, evidence the suitability of these SNFs in advances of energy storage devices. The rheological behaviour of PEG200/ZnO materials is carried out at different temperatures ranging from 303.15 to 323.15 K, which illustrates the Newtonian characteristics of these nanofluids with moderate dynamic viscosity and activation energy, and therefore, they could be utilized as effective heat transfer materials in photovoltaic/thermal devices and systems.

EFFECT OF BARRIER DISCHARGE AT ATMOSPHERIC PRESSURE ON GERMINATION ENERGY AND GERMINATION OF COTTON VARIETY "FLORA" IN THE OPEN GROUND

In the conducted experiment, cotton seeds were treated with barrier discharges in air for 4 and 6 minutes. Barrier discharges are discharges in which the current flow is limited by the distinctive dimensions of at least one dielectric layer and electrode. It is noticeably larger than the size of the gap between the electrodes, which is a high pressure (more than many hundreds of Tor), spatial heterogeneity and short duration of different physical and chemical processes: the plasma BR is in strongly non-equilibrium criteria average temperature of electrons is a few electro-volts, and the temperature of the gas is close to the temperature of the dielectric barrier. This treatment is symmetric and sufficiently studied, since the electric field separation in the discharge zone can be considered uniform if the gap between the electrodes is rather narrow. Atmospheric pressure plasma is in demand for agriculture, stimulating dielectric, barrier discharge plasma at atmospheric pressure for 4 and 6 min irradiation to stimulate plant growth, germination energy and germination rate.

Parasitic Capacitance in High-Density Neural Electrode Arrays: Sources and Evaluation Methods.

This study aims to identify sources of parasitic capacitance in high-density neural electrode arrays and to provide an approach for evaluating their associated capacitance values. We also represent the effect of parasitic capacitance on the electrochemical properties of electrodes. Electrochemical impedance spectroscopy (EIS) and voltage transient (VT) measurements were employed to assess the parasitic capacitance of a 16-channel ultramicro-sized electrode array (UMEA) (8×25 μm2 electrode sites). The effect of parasitic capacitance on cyclic voltammetry (CV), EIS, and VT measurements of 20-μm diameter electrodes was assessed by comparing two different array designs: narrow and wide trace arrays. The capacitive leakage currents and charge during CV measurements were not significant, however, during current pulsing 34% underestimation of the maximum charge injection capacity corresponded to capacitive leakage. Capacitive leakage during EIS resulted in an underestimation of the electrode impedance at frequencies >1.5 kHz. The electrode design and insulation thickness can play a significant role in determining the amount of capacitive leakage during current pulsing and EIS at higher frequencies. Determining the sources and levels of capacitive leakage current in high-density neural electrode arrays, enables us to correct the measured value for the leakage current and thus estimate the electrode impedance and stimulation thresholds more accurately. This study highlights the importance of electrode design in developing high-density arrays with minimum capacitive leakage.

Achieving Ultrahigh DC-Power Triboelectric Nanogenerators by Lightning Rod-Inspired Field Emission Modeling.

Direct current triboelectric nanogenerators (DC-TENGs) are a groundbreaking technology to capture micromechanical energy from the natural environment, which is crucial for directly powering sensor networks. However, the research bottleneck in enhancing the triboelectric electrification capability and charge storage capability of dielectrics has hindered the overall performance breakthroughs of the DC-TENG. Here, a field emission model-based DC-TENG (FEM-TENG) is proposed, inspired by lightning rods. The enhanced local electric field between dielectric materials and electrodes induces strong electron tunneling, which improves charge neutralization on the surface of materials and their internal charge storage space, thereby utilizing the dielectric volume effect effectively and strengthening triboelectricity. Guided by the field emission model, the FEM-TENG with a historic crest factor of 1.00375 achieves a groundbreaking record of an average power density of 16.061 W m-2 Hz-1 (1,591 W m-3 Hz-1), which is 5.36-fold of the latest DC-TENG. In particular, the FEM-TENG with high durability (100%) truly realizes the collection of breeze energy and continuously drives 50 thermohygrometers. Four additional applications exemplify the FEM-TENG, enabling comprehensive sensing of land, water, and air. This work proposes a paradigm strategy for the in-depth utilization of dielectric films, aiming to enhance the output power of DC-TENGs.

Material Selection for PMEDM Process

Powder Mixed Electro-Discharge Machining (PMEDM) is a non-traditional machining process. This method is used more and more to machine complex surfaces, parts made from materials with high hardness. Three indispensable components in PMEDM are powder, dielectric fluid and electrode. These components have a great influence on the efficiency of the machining process. This study was conducted to choose the best types for all three components mentioned above. The numbers of powder types, dielectric fluid types and electrode material types considered were ten, three and seven, respectively. The weight of each criterion in each product category was calculated using the two methods Rank Order Centroid (ROC) and Rank Sum (RS). In each case, the two methods were used to rank the alternatives are Faire Un Choix Adéquat (FUCA) (in French) and Measurement of Alternatives and Ranking according to COmpromise Solution (MARCOS). The optimal option will be found from the results of ranking the alternatives. The results of ranking the alternatives were also subjected to sensitivity analysis by using Sperman coefficient. This study discovered that the best option found when using the FUCA method is also the best option found when using the MARCOS method, and the best option that was found does not depend on the used weighting method.

High DC-Bias Stability and Reliability in BaTiO3-Based Multilayer Ceramic Capacitors: The Role of the Core-Shell Structure and the Electrode.

With the miniaturization of multilayer ceramic capacitors (MLCCs) and the increase of the electric field on a single dielectric layer, dielectric constant DC-bias stability and reliability have gradually aroused attention in the advanced electronics industry. In this study, MLCCs with outstanding DC-bias stability and reliability were prepared by using dielectric ceramic optimization and electrode optimization strategies. The effect of the Dy-Y doping concentration on the microstructure, dielectric properties, and reliability of BaTiO3-based ceramics was investigated. The shell ratio and effective shell doping concentration of the core-shell structure in ceramic grains play important roles in defects and electrical performances. The ceramic with appropriate doping contents shows a dielectric constant of 1800 and a dielectric constant change rate of -17% under a DC field of 4 kV/mm, which was fabricated into prototype MLCCs with different Ni electrodes. MLCCs exhibit outstanding DC-bias stability with a -28% degradation in the dielectric constant under a DC field of 4 kV/mm while possessing a dielectric constant of 2300 and satisfying the EIA X7S specification. Additionally, it was discovered that MLCCs prepared by using fine-size Ni particle electrodes have low electrode roughness and high interfacial Schottky barriers, resulting in better reliability. This study provides promising candidate materials and theoretical references for high-end and high DC-bias stability MLCCs.

Electrostatic-hydraulic coupled soft actuator for micropump application

The development of a soft actuator with high displacement is crucial for the effective operation of micropumps, ensuring a high fluid pump rate. This study introduces an innovative approach by presenting the design and fabrication of a novel electrostatic-hydraulic coupled soft actuator for a micropump within a microfluidic system. This pioneering soft actuator, leveraging electrostatic-hydraulic coupling, showcases a unique solution to enhance the performance of micropumps. The versatility of such a soft actuator makes it particularly promising for biomedical applications. The actuator comprises dielectric fluid in an elastomeric shell and electrodes to form the out-of-plane fluid-amplified displacement. This displacement amplification was used to generate a pumping actuation in the micropump. The actuator was characterized in terms of dielectric fluid volume, electrode size, temporal response, and amplification displacement. The soft actuator showed a maximum amplified displacement of 0.51 mm at 10 kV of the applied voltage, but a higher voltage caused a dielectric breakdown. Moreover, the actuator demonstrated the ability to operate at frequencies of 0.25 Hz and 0.1 Hz. The results of the study indicate that the fabricated electrostatic-hydraulic coupled soft actuator is a dependable and effective method of actuation for a micropump in a microfluidic system. The experimental characterization of the micropump revealed a maximum flow rate of 2304 μl min−1.

Microstructured Polyfluoroacrylate Elastomeric Dielectric Layer for Highly Stretchable Wide-Range Capacitive Pressure Sensors.

Capacitive pressure sensors capable of replicating human tactile senses have garnered tremendous attention. Introducing microstructures into the dielectric layer is an effective approach to improve the sensitivity of the sensors. However, most reported processes to fabricate microstructured dielectric layers are complicated and time-consuming and usually have adverse effects on the mechanical properties. Herein, we report a mechanically strong and highly stretchable dielectric layer fabricated from a microstructured fluorinated elastomer with a high dielectric constant (5.8 at 1000 Hz) via a simple and low-cost thermal decomposition process. Capacitive pressure sensors based on this microstructured fluorinated elastomer dielectric layer and soft ionotronic electrodes illustrate an impressing stretchability (>300%), a high pressure sensitivity (17 MPa-1), a wide detection range (70 Pa-800 kPa), and a fast response time (below 300 ms). Moreover, the multipixel capacitive pressure sensors sensing array maintains the unique spatial tactile sensing performance even under significant tensile deformation. It is believed that our microstructured fluorinated elastomer dielectric layer might find wide applications in stretchable ionotronic devices.

Excellent Miniature Thin Film Dielectric Elastomer Sensors for Robot Fingers Used in Human-Robot Interaction

Traditional sensors used to measure properties such as deformation and pressure often use materials such as metals, ceramics, piezos and polymers. However, since many of these materials are hard, it can be difficult to measure them with a single sensor when the pressure or elongation applied to the object changes. In this experiment, a dielectric elastomer thin-film pressure sensor (0.2 mm) was fabricated using hydrogenated nitrile rubber with significantly improved hardness and elongation. This single sensor can accurately measure pressure from 1gf to 20kgf. Also, the response speed was 50ms, which was sufficiently fast. A dielectric elastomer stretch sensor was also developed. This sensor uses elastic and flexible single-walled carbon nanotubes as dielectric elastomer electrodes for the hydrogenated nitrile rubber. This greatly improved the mechanical flexibility and stretchability of the stretch sensor, making it possible to operate it as a sensor even at 400% elongation. By attaching this stretch sensor to the robot's finger closely, it is possible to detect the dynamic movement of the robot's finger and to detect the force (pressure) when the fingertip touches the target object with the above pressure sensor. In addition, by using the small diaphragm-type dielectric elastomer actuator, it was confirmed that the sensation of the robot's touching an object could be fed back to the human finger. As a result, it is thought that the feeling of the robot’s finger touching an object could be driven more realistically and accurately. In addition, both a dielectric elastomer stretch sensor and a dielectric elastomer pressure sensor were attached to the finger of the robot, and the movement of the human’s finger was sensed and the force (pressure) when the finger touched the object was also able to be detected.

A simple electrode insulation and channel fabrication technique for high-electric field microfluidics

A simple and robust electrode insulation technique that can withstand a voltage as high as , which is equivalent to an electric field strength of MV m−1 across a channel filled with an electrolyte of conductivity S m−1, i.e. higher than sea water’s conductivity, is introduced. A multi-dielectric layers approach is adopted to fabricate the blocked electrodes, which helps reduce the number of material defects. Dielectric insulation with an exceptional breakdown electric field strength for an electrolyte confined between electrodes can have a wide range of applications in microfluidics, like high electric field strength-based dielectrophoresis. The voltage-current characteristics are studied for various concentrations of sodium chloride solution to estimate the insulation strength of the proposed materials, and the breakdown strength is calculated at the point where the electrical insulation failed. A detailed adhesion technique is also demonstrated, which will reduce the ambiguity around the fabrication of a sealed channel using SU-8.

ONE-STAGE ELECTROCHEMICAL SYNTHESIS OF A POLYMETHYLOLACRYLAMIDE/ULTRAFINE POLYTETRAFLUOROETHYLENE COMPOSITE

A method for one-stage electrochemical synthesis of a composite consisting of two non-conductive polymers has been developed. Using the example of electropolymerization of acrylamide in the presence of particles of ultrafine polytetrafluoroethylene (UPTFE), it is shown that the electrochemical approach makes it possible to simplify the traditional multistage technologies for the formation of composite polymer materials by combining in one process the electropolymerization of acrylamide and the formation of a polymethylolacrylamide (PMAA) film on the cathode, the capture of UPTFE particles by a growing polymer matrix, and formation of a PMAA/UPTFE composite. This technology makes it possible to reduce the total time for creating a polymer/polymer composite to 5-10 minutes. A procedure for the preparation of stable aqueous dispersions of UPTFE has been developed. It has been established that the most effective stabilizers of UPTFE aqueous dispersion are sodium lauryl sulfate (LS) and siloxane-acrylate emulsion SE 13-36. The formation of the PMAA/UPTFE composite was confirmed by XRD, SEM, SAXS, and spectrophotometry. It was found that the composite includes both large (~1 μm) and nanosized (1–10) nm UPTFE particles. The color of the PMAA/UPTFE composite films changes from colorless and transparent, characteristic of PMAA, to milky white (color of UPTFE and SE 13-36). This reduces the light transmission of composite films, reaching the minimum value for PMAA/UPTFE/SE 13-36. The mass of the PMAA/UPTFE composite increases with increasing electropolymerization time, and the residual current, which characterizes the degree of electrode insulation, decreases in comparison with the PMAA coating. Modification of the film with ultrafine polytetrafluoroethylene leads to a decrease in the swelling of composite coatings by a factor of 1.26–2.60, depending on the nature and concentration of the additive. The maximum insulating effect and reduced swelling is achieved for the PMAA/UPTFE(LS) composite, which indicates the preferred use of UPTFE(LS) for the modification of PMAA. The thermal stability of the PMAA/UPTFE(LS) composite and matrix PMAA is almost identical.

Study on the coaxial electrode in electrohydraulic shockwave drilling technology

In recent years, electrohydraulic shockwave drilling technology has been widely studied to improve the drill rate of deep and ultra-deep wells. However, few studies have been conducted on coaxial electrodes that are more suitable for drilling. Therefore, it is of great significance to study the discharge characteristics of coaxial electrodes and the influence of various factors on their discharge effects. Firstly, the electric field models of the coaxial electrode were established and simulated using the CST software. The results showed that the electrical breakdown occur randomly on the circular edge of the coaxial electrode. Abnormal electrical breakdown may occur at the junction of anode and insulation layer, which may damage the insulation layer, and this has also been verified in the experiments. Secondly, the influence of various parameters on the discharge effect was further studied based on the model. The results showed that higher voltage and liquid dielectric constant can effectively enhance the electrical breakdown ability. Larger or smaller electrode spacing and insulation concave depth can reduce the discharge effect or more damage the insulating layer. A smaller anode diameter has a stronger electrical breakdown ability, but the final shock wave becomes smaller. Finally, electrical breakdown experiment and rock breaking experiment were conducted to verify the simulation results. In summary, this study conducted in-depth research on coaxial electrodes through CST electric field simulation and experiments, which provided a basis for coaxial electrode design and can effectively promote the practical application of electrohydraulic shockwave technology.

A cerebral cortex-like structured metallized elastomer for high-performance triboelectric nanogenerator

The advancement of wearable electronics, particularly triboelectric nanogenerators (TENGs), relies on the development of flexible, stretchable, and compressible electrodes that possess a large active surface area, high electrical conductivity, and excellent mechanical stability and deformability. However, existing elastomeric electrodes face challenges in meeting all of these requirements. Herein, we present a novel approach to address these limitations and create electrodes with elastomeric properties, stable metal-like electrical conductivity, and an expanded active surface area. For this goal, we perform an assembly of metal nanoparticles (NPs) in toluene and amine-functionalized organic linkers in alcohol onto the thiol-functionalized, embossed-structured elastomer. Particularly, the assembly process involves ligand exchange reaction-mediated metal NPs and subjecting them to solvent-swelling/deswelling of the embossed PDMS. This process induces the formation of cerebral cortex-like structured elastomer electrode, which is subsequently electroplated with Ni. The resulting electrodes exhibit metal-like electrical conductivity, elastomer-like flexibility, and cerebral cortex-like structure with substantially large surface area and high stress relieving properties. When combined with an intaglio-structured dielectric PDMS electrode, the device exhibits impressive TENG performance, surpassing the performance of conventional TENGs. This approach provides a basis for developing and designing a variety of high-performance flexible electronics, including TENGs.