Application Of Electric Field Research Articles

Molecular Structures, Dipole Moments, and Electronic Properties of β-HMX under External Electric Field from First-Principles Calculations.

In order to investigate the impact of an external electric field on the sensitivity of β-HMX explosives, we employ first-principles calculations to determine the molecular structure, dipole moment, and electronic properties of both β-HMX crystals and individual β-HMX molecules under varying electric fields. When the external electric field is increasing along the [100], [010], and [001] crystallographic directions of β-HMX, the calculation results indicate that an increase in the bond length (N1-N3/N1'-N3') of the triggering bond, an increase in the main Qnitro (N3, N3') value, an increase in the minimum surface electrostatic potential, and a decrease in band gap all contribute to a reduction in its stability. Among these directions, the [010] direction exhibits the highest sensitivity, which can be attributed to the significantly smaller effective mass along the [010] direction compared with the [001] and [100] directions. Moreover, the application of an external electric field along the Y direction of the coordinate system on individual β-HMX molecules reveals that the strong polarization effect induced by the electric field enhances the decomposition of the N1-N3 bonds. In addition, due to the periodic potential energy of β-HXM crystal, the polarization effect of β-HMX crystal caused by an external electric field is much smaller than that of a single β-HXM molecule.

Electric-field tunable Type-I to Type-II band alignment transition in MoSe2/WS2 heterobilayers

Semiconductor heterojunctions are ubiquitous components of modern electronics. Their properties depend crucially on the band alignment at the interface, which may exhibit straddling gap (type-I), staggered gap (type-II) or broken gap (type-III). The distinct characteristics and applications associated with each alignment make it highly desirable to switch between them within a single material. Here we demonstrate an electrically tunable transition between type-I and type-II band alignments in MoSe2/WS2 heterobilayers by investigating their luminescence and photocurrent characteristics. In their intrinsic state, these heterobilayers exhibit a type-I band alignment, resulting in the dominant intralayer exciton luminescence from MoSe2. However, the application of a strong interlayer electric field induces a transition to a type-II band alignment, leading to pronounced interlayer exciton luminescence. Furthermore, the formation of the interlayer exciton state traps free carriers at the interface, leading to the suppression of interlayer photocurrent and highly nonlinear photocurrent-voltage characteristics. This breakthrough in electrical band alignment control, interlayer exciton manipulation, and carrier trapping heralds a new era of versatile optical and (opto)electronic devices composed of van der Waals heterostructures.

Applied electric field induced the change of spin-electron of the Fe3GeTe2 to improve its oxygen evolution reaction performance

Utilizing density functional theory (DFT) calculations, we investigate the influence of the external electric field on the oxygen evolution reaction (OER) performance of monolayer Fe3GeTe2. Monolayer Fe3GeTe2 has ferromagnetic metal properties and displays excellent electrocatalytic activity. The magnetism mainly comes from FeI atoms, owing to the strong Fe-Te orbitals hybridization, and FeI atoms have great effect on the active site Te atoms. The electric field induces the change of spin-electron and promotes charge redistribution in the Fe3GeTe2, resulting in the changes of the magnetic moment and magnetic anisotropic energy (MAE). Simultaneously, the applied electric field shifts the energy band and decreases the work function which facilitates carrier migration to the surface. Therefore, the OER overpotential is reduced and the catalytic performance is improved. These valuable findings can serve as vital references for the design of 2D magnetic electrocatalysts.

Efficient reverse water gas shift reaction at low temperatures over an iron supported catalyst under an electric field

The development of high-performance Fe-based catalysts is attractive because Fe is a cost-effective and earth-abundant element. Application of an external electric field and an appropriate catalytic support to an Fe-based catalyst enabled the reverse water–gas shift reaction to proceed with high activity, selectivity, and durability even at the low temperature of 423 K. The Fe-supported catalyst showed superior CO selectivity (≈ 100%) compared to the Co- or Ni-supported catalyst. The apparent activation energy (5.9 kJ mol−1) over the Fe/Ce0.4Al0.1Zr0.5O2 catalyst under an electric field was much lower than that without an electric field (61.4 kJ mol−1).

Influence of alternating electric field on electrorheological effect of aqueous dispersions of stevensite

Upon deionization of the aqueous dispersion of stevensite, a type of smectite clay minerals, a low-viscosity colorless transparent dispersion is obtained. The phenomenon known as the electrorheological (ER) effect has been previously reported when a weak electric field of several V/mm is applied to the stevensite aqueous dispersion. In this study, the influence of the waveform and frequency of the electric field was investigated while keeping the electric field intensity constant. It was observed that as the acceleration of the applied electric field intensity increased, the stress response to the electric field improved. Increasing the frequency of the electric field led to a reduction in the induced stress; however, it improved the response rate of stress. It has been indicated that even at higher electric field frequencies, the potential for observing the ER effect exists with higher electric field intensities. Maintaining a low electrolyte concentration may facilitate the development of novel ER fluids capable of instantaneously responding to the application or removal of electric fields.

Acceleration of flow-focused liquid jets in the presence of a strong electric field

This paper investigates the acceleration of flow-focused micro-jets under an applied external electric field. Such thin and fast jets are needed, for example, to deliver protein crystals in X-ray free electron laser experiments. This contribution focuses on analysing the acceleration of liquid jets produced from 50 % vol water and ethanol mixture. Such jets are focused with nitrogen gas and are subjected to 0 - 7 kV electric potential between a submerged electrode and an external electrode downstream of the nozzle. To gain insights into jet geometric properties an automatic image recognition and computer vision algorithm is utilised on already published data. Jet velocities and acceleration calculated for two jetting regimes show that application of external electric field accelerates the jets up to four orders of magnitude larger than the conventional micro-jets.

A Many-Shells Model for Cell Transmembrane Potentials for Pulsed Electric Field Applications

A Many-Shells Model for Cell Transmembrane Potentials for Pulsed Electric Field Applications

A Novel, Compact SSMG Architecture for Portable Pulsed Electric Field Applications

A Novel, Compact SSMG Architecture for Portable Pulsed Electric Field Applications

Over 30 Years of DiI Use for Human Neuroanatomical Tract Tracing: A Scoping Review.

In the present study, we conducted a scoping review to provide an overview of the existing literature on the carbocyanine dye DiI, in human neuroanatomical tract tracing. The PubMed, Scopus, and Web of Science databases were systematically searched. We identified 61 studies published during the last three decades. While studies incorporated specimens across human life from the embryonic stage onwards, the majority of studies focused on adult human tissue. Studies that utilized peripheral nervous system (PNS) tissue were a minority, with the majority of studies focusing on the central nervous system (CNS). The most common topic of interest in previous tract tracing investigations was the connectivity of the visual pathway. DiI crystals were more commonly applied. Nevertheless, several studies utilized DiI in a paste or dissolved form. The maximum tracing distance and tracing speed achieved was, respectively, 70 mm and 1 mm/h. We identified studies that focused on optimizing tracing efficacy by varying parameters such as fixation, incubation temperature, dye re-application, or the application of electric fields. Additional studies aimed at broadening the scope of DiI use by assessing the utility of archival tissue and compatibility of tissue clearing in DiI applications. A combination of DiI tracing and immunohistochemistry in double-labeling studies have been shown to provide the means for assessing connectivity of phenotypically defined human CNS and PNS neuronal populations.

Mechanical Characterization of the Erythrocyte Membrane Using a Capacitor-Based Technique.

Pathological processes often change the mechanical properties of cells. Increased rigidity could be a marker of cellular malfunction. Erythrocytes are a type of cell that deforms to squeeze through tiny capillaries; changes in their rigidity can dramatically affect their functionality. Furthermore, differences in the homeostatic elasticity of the cell can be used as a tool for diagnosis and even for choosing the adequate treatment for some illnesses. More accurate types of equipment needed to study biomechanical phenomena at the single-cell level are very costly and thus out of reach for many laboratories around the world. This study presents a simple and low-cost technique to study the rigidity of red blood cells (RBCs) through the application of electric fields in a hand-made microfluidic chamber that uses a capacitor principle. As RBCs are deformed with the application of voltage, cells are observed under a light microscope. From mechanical force vs. deformation data, the elastic constant of the cells is determined. The results obtained with the capacitor-based method were compared with those obtained using optical tweezers, finding good agreement. In addition, P. falciparum-infected erythrocytes were tested with the electric field applicator. Our technique provides a simple means of testing the mechanical properties of individual cells.

Large pyroelectric energy conversion in lead scandium tantalate thin films

Non-linear pyroelectric energy harvesting using ferroelectric thin films exhibits high energy conversion, primarily due to their large breakdown field compared to bulks. Here, we report the pyroelectric energy conversion potential of lead scandium tantalate, Pb(Sc1/2Ta1/2)O3 (PST) thin film fabricated on a c-sapphire substrate using chemical solution deposition. To enable the application of high electric field and to assess the pyroelectric energy conversion performance, interdigitated electrodes were deposited on the PST thin film. A maximum harvested energy density of 9.1 J cm−3 per cycle was deduced from polarization measurements in films undergoing an Olsen cycle between 0 °C and 150 °C when the electric field was varied between 50 and 1500 kV/cm. Furthermore, PST thin films can reach up to 27 % of Carnot efficiency for a temperature interval of 10 K between 30 °C and 40 °C. This study highlights the significance of PST thin films for electro-thermal energy harvesting and promising opportunities for enhancing the conversion efficiency and power density using thin films or thin film multi-layer capacitors in the future for thermal energy harvesting.

Highly tunable electronic properties in γ-XSe (X = Ge and Sn) bilayer with strain and electric field

The recent experimental synthesis of the monolayer γ-GeSe, characterized by its unique Mexican-hat band dispersion, has attracted considerable research interest. However, the exploration of band gap engineering in bilayer γ-GeSe and γ-SnSe through the application of strain and electric fields remains under-investigated. In this study, we demonstrate that both strain and electric fields are effective methods for band gap engineering in bilayer γ-GeSe and γ-SnSe. We have discovered that strain can not only tune the band gap but also induce a transition from an indirect to a direct band gap. Furthermore, it is observed that the band gap of bilayer γ-GeSe and γ-SnSe can be modulated by an electric field, potentially leading to a transition from semiconductor to metal. Our findings suggest that band gap engineering via strain and electric fields is a promising approach for designing nanoelectronic and optoelectronic devices based on bilayer γ-GeSe and γ-SnSe.

Phase composition, crystal structure and ferroelectric properties of Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/si(001) heterostructures

Phase composition, nanostructure and properties of Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/Si(001) heterostructures have been studied by X-ray diffraction, scanning probe microscopy, and dielectric spectroscopy. Sr0.6Ba0.4Nb2O6 and Ba2NdFeNb4O15 films were fabricated under identical conditions by RF cathode sputtering in an oxygen atmosphere. It was shown that the obtained heterostructures were pure, the Sr0.6Ba0.4Nb2O6 and Ba2NdFeNb4O15 layers were polycrystalline textured, and the layer thickness did not affect the unit cell strain. The heterostructure exhibited a ferroelectric-like response, but the polarized regions arising under the application of electric field were unstable at room temperature. The reasons for the identified regularities are discussed.

Multiscale insights into electric field orientation effects on piezoelectric strain and crystallography in P(VDF–TrFE) and P(VDF–TrFE–CTFE) fibers

This research primarily focuses on the effect of changing electric field directions on the crystal structure of piezoelectric fibers, notably, P(VDF–TrFE) and P(VDF–TrFE–CTFE). The study also explores the deformation mechanisms of fibers at micro- and nanoscales. A significant aspect of the research involves the application of parallel and perpendicular electric fields and observation of their impact on fiber properties. In situ wide-angle X-ray diffraction (WAXD) studies are crucial for determining the nanoscale properties when the electric field orientations change. The results show that the direction of the electric field significantly affects the sign (positive or negative) of the dipole vector within the β-crystal lattice structure of the fibers. This can be attributed to the rotation of dipole vectors in response to the electric field–fiber alignment angle. Furthermore, the research identifies the crystal plane (201,111)β as exhibiting the highest magnitude of piezoelectric response strain in the β phase. The study also employs scanning electron microscopy and digital image correlation (DIC) to reveal the material's morphology and to assess fiber strain distribution at the micrometer scale under different voltages. DIC results particularly highlight that stress concentration leads to the deformation of fibers into voids, which are spaces between fibers created by electrospinning. This work comprehensively elucidates how deformation works in piezoelectric polymers by connecting large-scale changes observed in fibers through DIC and small-scale changes observed in WAXD studies presenting the piezoelectric strain responses at the crystal plane.

Quickly Formed Continuously Tuneable Laser in the Full Visible Spectrum Using Cholesteric Liquid Crystal Cells Based on the Electrothermal Effect

AbstractWavelength‐tuneable lasers can play a crucial role across many fields, and their applications continue to expand with advancements. Cholesteric liquid crystal (CLC) devices are developed, enabling good wavelength‐tuneable lasers. In CLC devices, pitch control is required to tune the desired wavelength. However, pitch control takes a long time and is difficult, which limits the speed and range of laser wavelength tuning. Here, by applying a voltage once and forming an electric field gradient along the wedge direction in the CLC wedge cell, we could realize CLC pitch gradient arrays that achieve continuous wavelength tuning over 500 nm in only 10 min through the electrothermal effect while continuously generating laser lines in the full visible spectrum. The laser wavelength could be rapidly tuned over the full visible spectrum by moving within the array in the wedge cell. The study of CLC cells for electric field application in real time is able to observe the dynamic process of pitch change directly. This new laser device and strategy has potential in many fields that require active laser tuning and is expected to lead to innovative changes in the development of future practical laser devices in the optical industry.

Electric-field-assisted fabrication of metal-class thermal-conductive and elastomer-class-flexible composites comprising plasma-surface-modified hexagonal boron nitride and polyrotaxane

There is a growing demand for materials with high thermal conductivity, electrical insulation, flexibility, and toughness for application in flexible electronic devices. To develop materials with the aforementioned properties, composites comprising the flexible and tough polyrotaxane (PR) and highly thermally conductive hexagonal boron nitride particles (hBN) were fabricated in this study. An electric field was applied during the polymerization of the composites to improve their thermal conductivity in the out-of-plane direction of the composites without reducing their flexibility. Electric-field application during polymerization controlled the orientation of hBN in the as-synthesized composites, forming pillar-like structures comprising oriented hBN. The particle diameter and concentration of hBN were optimized to synthesize an electrically insulating composite with elastomer-class flexibility in the in-plane direction (a low Young’s modulus of 77 MPa) and metallic-alloy-class thermal conductivity in the out-of-plane direction (>10 W/mK) with a wide range of potential applications including thermal interface materials in electronic devices.

Unveiling the electronic properties of BiP[formula omitted] triphosphide from bulk to graphene-based heterostructures by first-principles calculations

In our study, we investigated the structural and electronic properties of bismuth triphosphide (BiP3) in its bulk, few-layer, and monolayer forms. We found that BiP3 in bulk exhibits a metallic stable layered structure. The exfoliation energy of 1.07 J/m2 indicates ease exfoliation, comparable to other triphosphides. The band gap varies with thickness, transitioning from semiconductor–metal between four to five layers, influenced by interlayer coupling and quantum confinement. We also investigated the heterostructure created by depositing graphene (G) on few-layer BiP3. In monolayer (G/m-BiP3) and bilayer (G/2L-BiP3) forms, a metal–semiconductor junction is formed, characterized by weak vdW interactions at the interface and exhibiting p-type Schottky contacts. We observed that the Schottky Barrier Height (SBH) can be modulated by altering the interlayer distance between G and BiP3. This adjustment allows transitions between n-type and p-type Schottky contacts in G/m-BiP3 and the formation of an ohmic contact in G/2L-BiP3. Furthermore, applying an electric field affects the SBH, leading to similar transitions and the development of an ohmic contact. Additionally, our study shows that n-doping in graphene increases with the number of BiP3 layers and external electric field application. These properties position BiP3 few-layer as a promising material for nanoelectronic, optoelectronic, and graphene-based devices.

Design and application of a power frequency electric field measuring device for a high‐humidity environment

AbstractThe power frequency electric field is the most important electromagnetic environmental factor in alternating current power transmission projects. The humidity has a negative influence on available electric field measuring devices, which may lead to discrepancies of up to seven times the actual value at a relative humidity exceeding 80%. The changes in the support and probe shell impedance may be the reason for the error. The optimization measures include modifying the communication mode, designing a suitable structure and circuit for the probe, and using composite insulating material with strong hydrophobicity for the support. A three‐axis omnidirectional electric field measuring device was developed based on wireless communication and composite support. The variation of the measured electric field strength value is less than 1% at relative humidities ranging from 45% to 90% in the laboratory, and the measured results obtained in high humidity at the high‐voltage test site and under the transmission line demonstrated high accuracy. The research demonstrates that the composite support can be used to improve the performance of conventional devices. The proposed device can better meet the needs for accurate measurement of electric field strength in a high‐humidity environment and overcome the technical problems raised by the IEC standard.

Optimal Oriented External Electric Fields to Trigger a Barrierless Oxaphosphetane Ring Opening Step of the Wittig Reaction.

The Wittig reaction is one of the most important processes in organic chemistry for the asymmetric synthesis of olefinic compounds. In view of the increasingly acknowledged potentiality of the electric fields in promoting reactions, here we will consider the effect of the oriented external electric field (OEEF) on the second step of Wittig reaction (i. e. the ring opening oxaphosphetane) in a model system for non-stabilized ylides. In particular, we have determined the optimal direction and strength of the electric field that should be applied to annihilate the reaction barrier of the ring opening through the polarizable molecular electric dipole (PMED) model that we have recently developed. We conclude that the application of the optimal external electric field for the oxaphosphetane ring opening favours a Bestmann-like mechanism.

Molecular Simulations Reveal the Free Energy Landscape and Transition State of Membrane Electroporation.

The formation of pores over lipid membranes by the application of electric fields, termed membrane electroporation, is widely used in biotechnology and medicine to deliver drugs, vaccines, or genes into living cells. Continuum models for describing the free energy landscape of membrane electroporation were proposed decades ago, but they have never been tested against spatially detailed atomistic models. Using molecular dynamics (MD) simulations with a recently proposed reaction coordinate, we computed potentials of mean force of pore nucleation and pore expansion in lipid membranes at various transmembrane potentials. Whereas the free energies of pore expansion are compatible with previous continuum models, the experimentally important free energy barrier of pore nucleation is at variance with established models. The discrepancy originates from different geometries of the transition state; previous continuum models assumed the presence of a membrane-spanning defect throughout the process, whereas, according to the MD simulations, the transition state of pore nucleation is typically passed before a transmembrane defect has formed. A modified continuum model is presented that qualitatively agrees with the MD simulations. Using kinetics of pore opening together with transition state theory, our free energies of pore nucleation are in excellent agreement with previous experimental data.