Average Charge Transfer Research Articles

Analyzing bacterial detection and transport using redox impact electrochemistry

Understanding bacterial transport dynamics, particularly at the single-particle level, is crucial across diverse fields from environmental science to biomedical research. In recent times, the emerging impact electrochemistry method offers a transformative approach for detection of bacteria at the single-particle level. The method employs the principle of single-entity electrochemistry to scrutinize electrochemical processes during interaction with the working electrode. In this study, we utilized redox impact electrochemistry to detect bacteria and analyze their transport processes towards the working electrode. Stochastic detection using redox reactions at the ultramicroelectrode enabled the detection of individual bacteria, with collision resulting in a current spike signal due to charge transfer. Notably, the detection of bacteria was demonstrated at an exceptionally low concentration (100 CFU/mL), with recorded current spikes reaching approximately 8.1 nA. Analysis of integrated areas under these spikes unveiled a diverse distribution of charge transfer at the ultramicroelectrode during redox reactions, implying variations in bacterial sizes, collision positions on the electrode surface, and redox activity among bacteria. Remarkably, the average charge transfer per bacterium between E. coli and the electrode was found to be (244 ± 24) pC, underscoring the intrinsic redox activity of the bacteria, equivalent to (2.52 ± 0.25) × 10−15 mol. Additionally, our investigation explored the effects of cell transport mechanisms, including diffusion, migration, convection, and settlement on stochastic interactions of the bacteria at the ultramicroelectrode. Through the collision frequency calculations, we found that migration is the primary factor shaping bacterial transport, with gravitational cell settlement also exerting a significant influence.

Controlled dynamic variation of interfacial electronic and optical properties of lithium intercalated ZrO2/MoS2 vdW heterostructure

Efficient strategies for modifying the characteristics of van der Waals (vdW) layered materials in a precise and reversible mode remain challenging. Our suggested method for customization entails the implementation of layer-sliding and intercalation. In this work, a norm-conserving approach within the context of density functional theory has been used to examine the electronic and optical properties of two-dimensional (2D) van der Waals heterostructure (vdWHS), which is modeled by using 2D zirconium dioxide (1T-ZrO2) and molybdenum disulfide (1T-MoS2) monolayers of similar phase. Both contributing monolayers have similar lattice structures, with a minimum lattice mismatch of 0.83 %, and have corrugation on both sides that can successfully retain foreign species at the vdW-gap. In the next step, interfacial engineering through Li-intercalation and layer-sliding was employed to modify physical properties of the vdWHS. It is the worth mentioning that a narrow bandgap of 0.102 eV (0.22 eV) has been observed in the unintercalated ZrO2/MoS2 vdWHS when employing PW-LDA (hybrid-functional). Li-intercalation and sliding process significantly influenced the electronic properties of the studied vdWHS. Furthermore, un-slided and fully-slided Li-intercalated vdWHS exhibit an increase in the vdW-gap by 3.78 % and 27.14 %, respectively, as compared to unintercalated vdWHS. To further understand the electrical behaviour at the interface of contributing monolayers, a comparative study has also been made for the variation in the planar average charge density difference, charge transfer, and interface dipole moment for unintercalated and intercalated vdWHS. In the unintercalated vdWHS, the calculated values of ΔQ and μ(z) provide evidence of significant charge transfer from 1T-ZrO2 to 1T-MoS2 before sliding, whereas in the fully-slided vdWHS, there is 80.11 % more charge transfer from 1T-MoS2 to 1T-ZrO2. Li-intercalation increases the magnitude of ΔQ (by 90.27 %) near 1T-MoS2, indicating a sufficient quantity of charge transfer from the 1T-MoS2 monolayer. The results of the anisotropic analysis show that the calculated in-plane and out-of-plane components of the real and imaginary parts of the dielectric function differ significantly. The optical absorption and energy losses of Li-intercalated vdWHS experience a substantial decrease of about 90 % and 50 %, respectively, as compared to unintercalated vdWHS. Our employed method promotes the notion that interfacial engineering through simultaneous layer-sliding and intercalation approach can be used to regulate and modify the physical properties of 2D insulator/metal based vdWHS.

Feeling the strain: Enhancing the electrochemical performance of olivine LiMnPO[formula omitted] as cathode materials for Li-ion batteries through strain effects

Currently, the improvement of Li-ion batteries (LIBs) is more important than ever, especially due to the increasing spread and rapid progress of electric vehicles and high-tech applications. Materials used for positive electrodes are one of the main constituents of batteries, which typically determine their electrochemical efficiency. Phospho-olivine LiMnPO4 (LMP) material has been regarded as a potential positive electrode material for LIBs due to its outstanding properties. However, it suffers from low electronic and ionic conductivity. Therefore, this work aims to overcome these drawbacks by applying a biaxial strain to LMP. In this regard, we used density functional theory calculations to investigate the effect of biaxial strain on the dynamic and thermal stabilities, structural, electronic, ionic diffusion, electrochemical potential, and defect properties of LiMnPO4 (LMP) structure, as well as on the Average (Mn–O, Li–O and P–O) bond lengths, electrical conductivity, and charge transfer. Moreover, the influence of anti-site defects on the ionic conductivity of LMP compound was evaluated. Our findings suggest that the biaxial tensile strain has a remarkable effect on the rate performance of LMP cathode material. A biaxial tensile strain of +2% reduces the band gap of LMP from 3.51 to 3.41 eV, and ameliorates the diffusion coefficient by 100 times. Furthermore, the migration barrier was calculated to be 0.37 eV for strained (+2%) defective MP, lower than 1.12 eV for unstrained defective MP, indicating that biaxial tensile strain can mitigate the negative effect of anti-site defects on Li-ion migration. These results can prompt us to suggest biaxial tensile strain as a good strategy for improving the electrochemical performance of LMP as cathode material for LIBs. Furthermore, this study may supply insights to cathode material designers and engineers on the importance of an appropriate biaxial strain value to improve the rate performance of LiMnPO4 as cathode materials for LIB batteries.

Achieving controllable multifunctionality through layer sliding

Dynamical variation of physical properties in a controllable fashion provides exciting possibilities to obtain multifunctional materials. In this work, layer-sliding is employed to modify the structural, interfacial electronic and optical properties of unintercalated and Mg-intercalated two-dimensional (2D) van der Waals heterostructure (vdW-HS) consisting of buckled silicene and hexagonal boron nitride (hBN). The most stable stacking configuration of silicene over hBN is screened out and then intercalated with Mg at the interface. Dynamical-dependent changes in the properties of vdW-HS are performed by sliding silicene over hBN monolayer in the absence and presence of the intercalant. Layer-sliding is carried out in equal length intervals, and various parametric quantities related to the physical characteristics of the vdW-HS are repeatedly calculated and compared. Apart from various parametric quantities, stability of unintercalated and Mg-intercalated vdW-HS is also checked by means of relative total energies, binding energies and vdW gaps along the sliding pathway. Comparison of binding energies shows that the un-slided, half-slided, and fully-slided Mg-intercalated vdW-HS are 1.52, 1.44 and 1.42 eV more stable than the unintercalated vdW-HS. Opening of a small band gap of 12, 31 and 28 meV for un-slided, half-slided and fully-slided unintercalated vdW-HS, respectively, is worth mentioning. To study the interfacial electronic behavior, planar average charge density difference (Δρ) and charge transfer (ΔQ) are also calculated and varied via layer-sliding. Further, we calculated diverse optical spectra such as the complex dielectric function (DF), electron energy loss function [L(ω)], diagonal components of dielectric tensor [ε(iω)], refractive index [n(ω)], extinction coefficient [k(ω)], absorption coefficient [α(ω)], and reflectivity [R(ω)] for un-slided, half-slided and fully-slided unintercalated and Mg-intercalated vdW-HS. Interestingly, the polarization and energy losses have been reduced in the case of Mg-intercalated vdW-HS. The suggested layer-sliding method can be established as a general scheme for bringing multifunctionality into a layered material.

Electrochemical Mechanism of the Preparation of High-Purity Indium by Electrodeposition.

Indium is a crucial material and is widely used in high-tech industries, and electrodeposition is an efficient method to recover rare metal resources. In this work, the electrochemical behavior of In3+ was investigated by using different electrochemical methods in electrolytes containing sodium and indium sulfate. Cyclic voltammetry (CV), chronoamperometry (CA), and alternating current impedance (EIS) techniques were used to investigate the reduction reaction of In3+ and the electrocrystallization mechanism of indium in the indium sulfate system. The cyclic voltammetry results showed that the electrodeposition process is irreversible. The average charge transfer coefficient a of In3+ was calculated to be 0.116 from the relationship between the cathodic peak potential and the half-peak potential, and the H+ discharge occurred at a higher negative potential of In3+. The nucleation mechanism of indium electrodeposition was analyzed by chronoamperometry. The mechanism of indium at potential steps of −0.3 to −0.6 V was close to diffusion-controlled instantaneous nucleation with a diffusion coefficient of 7.31 × 10−9 cm2 s−1. The EIS results demonstrated that the reduction process of In3+ is subject to a diffusion-controlled step when pH = 2.5 and the applied potential was −0.5 V. SEM and XRD techniques indicated that the cathodic products deposited on the titanium electrode have excellent cleanliness and purity.

Effect of Build Orientation and Annealing on Corrosion Resistance of Additively Manufactured Duplex Stainless Steel in 3.5% NaCl

Grade 2205 Duplex stainless steel (DSS) components were built via selective laser melting (SLM) with gas atomized powder (D90 < 45μm) using a 250 W laser in a nitrogen environment. The relative density was 99.1 ± 0.3%, and the ferrite/austenite phase ratio after annealing was 53.0/47.0 ± 4.8%. Two build orientations (parallel and perpendicular to build direction), as well as as-built SLM (no heat treatment) and annealed conditions, were studied. Corrosion properties were characterized in a 3.5% NaCl electrolyte and compared to 2205 wrought. The charge transfer resistance was > 500 kohm.cm2, and the corrosion rate was < 100 nA cm−2 for all alloys, which suggest passivity. No stable pit formation occurred during cyclic polarization tests although the as-built perpendicular and annealed SLM conditions showed metastable pitting, likely due to surface porosity and/or chemical inhomogeneity. The as-built parallel condition did not show metastable pitting and had the highest average charge transfer resistance, which is evidence of possible improvements from laser melted material, but not conclusive. Ultimately, all SLM DSS 2205 was similar to 2205 wrought, implying that the build orientation and annealing were not as significant of factors as the chemical composition in predicting the passivity and pitting resistance.

Explosive vapor detection using novel graphdiyne nanoribbons—a first-principles investigation

We investigated the capability of graphdiyne nanoribbon (GdNR) to detect the existence of explosive vapors like hexogen or cyclonite, hexamethylene triperoxide diamine (HMTD), and 2,4,6-trinitrotoluene (TNT) using ATK-VNL package. In order to determine the sensing response of GdNR towards these explosive vapors, the geometric firmness of the material is first verified with the assistance of cohesive energy. Then, electronic characteristics like the projected density of states (PDOS) spectrum, band structure, and electron density are examined for both isolated and explosive vapor adsorbed GdNR. Further, adsorption attributes like average energy gap variation, enthalpy adsorption, adsorption energy, and Bader charge transfer are explored for explosive vapor adsorbed GdNR. Moreover, there is a need for rapid detection of explosive vapors using solid-state chemical sensors. The scrutinization of these attributes affirms the employment of GdNR as a chief material in a chemical nanosensor to perceive the availability of the mentioned explosive vapors.

Electronic properties of novel bismuthene nanosheets with adsorption studies of G-series nerve agent molecules – a DFT outlook

In order to confirm the ability of bismuthene nanosheet in detecting the G-series nerve agents, electronic and adsorption properties are investigated. The alteration in the band gap is observed (from the energy band structure) upon adsorption of G-series nerve agents, which results in the modification in the conductivity of BiNS. In addition, to establish the potential application of BiNS as a nerve agent sensor, the adsorption energy, average energy gap variation and Bader charge transfer (vital adsorption properties) are evaluated for the nerve agents, which is physisorbed on BiNS. Furthermore, the supreme statement made in the existing research on adsorption of G-series nerve agents on BiNS is also claimed by comparing the electron density of isolated and nerve agents adsorbed BiNS.

In Situ Electrochemical Atomic Force Microscopy and Auger Electro Spectroscopy Study on the Passive Film Structure of 2024‐T3 Aluminum Alloy Combined with a Density Functional Theory Calculation

The initial growth of the passive films on the Al2CuMg particle and Al matrix in AA2024‐T3 are investigated by in situ electrochemical atomic force microscopy (ECAFM) and ex situ characterization techniques in citric acid. The passive films are mainly composed of Al2O3 (34%), Al(OH)3 (8.4%), AlOOH (27.2%), CuO (19.4%), and Cu2O (11%). ECAFM images display that the film on the Al2CuMg particle is flawed and loose. Auger electro spectroscopy (AES) results show that the thickness of the passive film on the Al2CuMg particle is 1.4 nm, which is thinner than that on the Al matrix (2.4 nm). The combined ECAFM and AES results demonstrate that the corrosion resistance of the passive film on the Al2CuMg is weaker than that on the Al matrix. According to the density functional theory (DFT) calculations, the average charge transfer and adsorption energy of the adsorbates (O2−/OH−/H2O) on the Al surfaces are larger than that on the Al2CuMg surfaces, meaning that O2 and H2O preferably dissociate and adsorb on the Al surfaces. Moreover, the electronic interactions between the adsorbates and Al surfaces are stronger. This is the reason that the growth rate of the passive film on the Al2CuMg particle is slower at initial stages.

The Alteration of Intrinsic Excitability and Synaptic Transmission in Lumbar Spinal Motor Neurons and Interneurons of Severe Spinal Muscular Atrophy Mice.

Spinal muscular atrophy (SMA) is the leading genetic cause of death in infants. Studies with mouse models have demonstrated increased excitability and loss of afferent proprioceptive synapses on motor neurons (MNs). To further understand functional changes in the motor neural network occurring in SMA, we studied the intrinsic excitability and synaptic transmission of both MNs and interneurons (INs) from ventral horn in the lumbar spinal cord in the survival motor neuron (SMN)Δ7 mouse model. We found significant differences in the membrane properties of MNs in SMA mice compared to littermate controls, including hyperpolarized resting membrane potential, increased input resistance and decreased membrane capacitance. Action potential (AP) properties in MNs from SMA mice were also different from controls, including decreased rheobase current, increased amplitude and an increased afterdepolarization (ADP) potential. The relationship between AP firing frequency and injected current was reduced in MNs, as was the threshold current, while the percentage of MNs showing long-lasting potentiation (LLP) in the intrinsic excitability was higher in SMA mice. INs showed a high rate of spontaneous firing, and those from SMA mice fired at higher frequency. INs from SMA mice showed little difference in their input-output relationship, threshold current, and plasticity in intrinsic excitability. The changes observed in both passive membrane and AP properties suggest greater overall excitability in both MNs and INs in SMA mice, with MNs showing more differences. There were also changes of synaptic currents in SMA mice. The average charge transfer per post-synaptic current of spontaneous excitatory and inhibitory synaptic currents (sEPSCs/sIPSCs) were lower in SMA MNs, while in INs sIPSC frequency was higher. Strikingly in light of the known loss of excitatory synapses on MNs, there was no difference in sEPSC frequency in MNs from SMA mice compared to controls. For miniature synaptic currents, mEPSC frequency was higher in SMA MNs, while for SMA INs, both mEPSC and mIPSC frequencies were higher. In SMA-affected mice we observed alterations of intrinsic and synaptic properties in both MNs and INs in the spinal motor network that may contribute to the pathophysiology, or alternatively, may be a compensatory response to preserve network function.

Adsorption studies of dimethyl and methyl-ethyl ester molecules on silicene nanoring: Application of DFT study

The electronic and adsorption properties of dimethyl and methyl-ethyl ester molecules on a silicene nanoring (SiNR) are studied using first-principles calculations. The adsorption properties of dimethyl and methyl-ethyl ester molecules on the surface of a silicene nanoring is investigated in terms of density of states spectrum, adsorption energy, average energy gap variation, Mulliken charge and Bader charge transfer. The structural stability of the SiNR is ensured using formation energy. The variation in the electron density and energy gap is noticed upon adsorption of dimethyl and methyl-ethyl ester molecules in the SiNR base material compared with its isolated counterpart. The highlights of the present work are silicene nanoring is used as a base material for ester molecule adsorption. The adsorption behavior of ester molecules is studied using energy band structure. The DOS spectrum confirms the transfer of electrons between the SiNR and ester molecules. The findings suggest that a SiNR can be used as a base material for the detection of dimethyl and methyl-ethyl ester molecules.

Probing cyanogen chloride gas molecules using blue phosphorene nanosheets based on adsorption properties: A first-principles study

The interaction behavior and sensing ability of cyanogen chloride (CNCl) molecules on blue phosphorene nanosheet (βP-NS) were explored using first-principles calculation. The geometric stability of both pristine and Al incorporated βP-NS are established by the formation energy. The core stimulus of the current research is to probe hazardous CNCl gas molecules using βP-nanostructures rapidly. The interaction of various orientation sites of CNCl on βP-base material is investigated in association with the adsorption energy, average band gap changes, band gap, and Bader charge transfer. Furthermore, the exothermicity of adsorption energy is perceived upon the interaction of CNCl gas on βP-material, which varies from −0.151 to −0.653 eV. The findings of the proposed research recommend that the βP-NS can be employed for fast probing of CNCl toxic gas molecules and the sensing ability of CNCl improves with the substitution of Al in βP-nanosheets.

The electrochemistry and kinetics of the oxidative dissolution of chalcopyrite in ammoniacal solutions: Part I – Anodic Reactions

The oxidative dissolution of chalcopyrite in aqueous solutions is an electrochemical process. Such processes can be evaluated as coupled anodic and cathodic reactions using electrochemical techniques. The chalcopyrite dissolution reaction has been studied in ammonia-ammonium sulphate solutions using potentiostatic and potentiodynamic methods. Anodic current densities in the vicinity of the mixed potential have been found to increase with an increase in total ammonia (NH3 + NH4+) from 1 M to 3 M, and the order of reaction was found to be 1st order with respect to ammonia. The reaction was found to be zero order with respect to [OH−] at a pH between 9 and pH 10. An analysis of the Tafel slopes suggested an average charge transfer coefficient of 0.61. The rate controlling step was concluded to be a single electron transfer reaction, which supports the formation of a copper depleted intermediate surface that is rapidly oxidised in subsequent electron transfer reactions. The anodic sweeps and constant potential tests did not support the formation of a passivating surface deposit on the oxidising chalcopyrite surface.

Matlab software for impedance spectroscopy designed for neuroscience applications

BackgroundMetal electrodes are a mainstay of neuroscience. Characterization of the electrical impedance properties of these cuffs is important to ensure successful and repeatable fabrication, achieve a target impedance, revise novel designs, and quantify the success or failure of implantation and any potential subsequent damage or encapsulation by scar tissue. New methodsImpedances are frequently characterized using lumped-parameter circuit models of the electrode–electrolyte interface. Open-source tools to gather and analyze these frequency sweep data are lacking. Here, we present such software, in the form of Matlab code, which includes a GUI. It automatically acquires frequency sweep data and subsequently fits a simplified Randles model to these data, over a user specified frequency range, providing the user with the model parameter estimates. Also, it can measure an unknown impedance of an element over a range of frequencies, as long as an external resistor can be added for the measurements. ResultsThe tool was tested on five bright platinum nerve cuffs in vitro. The average charge transfer resistance, solution resistance, CPE value, and impedance magnitude were estimated. Comparison to existing methodsThe measured values of the impedance of cuffs were in agreement with the literature (Wei and Grill, 2009). Variation between cuffs fabricated as consistently as possible amounted to 10% for impedance magnitude and 4° for impedance phase. ConclusionThe results show that this low-cost tool can be used to characterize a cuff across different conditions including after implantation. The latter makes it useful for a longer-term study of electrode viability.

Ab initio electronic structure, bonding and optical properties of two relatively new ceramics Hf2Al3C4 and Hf3Al3C5: A comparative study

The structural, electronic and optical properties of the ternary carbides Hf2Al3C4 and Hf3Al3C5 are studied via first principles orthogonalized linear combination of atomic orbitals (OLCAO) method. Results on crystal structure, interatomic bonding, band structure, total and partial density of states (DOS), localization index (LI), effective charge (Q*), bond order (BO), dielectric function (ε), optical conductivity (σ) and electron energy loss function are presented and discussed in detail. The band structure plots show the conducting nature of Hf2Al3C4 and Hf3Al3C5 carbides. DOS results disclose that the total number of states at Fermi level N(EF) are 1.89 and 2.38 states/(eV unit cell) for Hf2Al3C4 and Hf3Al3C5 respectively. The Q* calculations show an average charge transfer of 0.723 and 0.711 electrons from Hf and 0.809 and 0.807 electrons from Al to C sites in Hf2Al3C4 and Hf3Al3C5 respectively. The BO results provide the dominating role of Al–C bonds with BO value of 6.62 (BO% = 59%) and 6.66 (BO% = 49%) for Hf2Al3C4 and Hf3Al3C5 respectively and are considered responsible for the crystals cohesion. The LI results reflect the presence of highly delocalized states in the vicinity of the Fermi level. The dielectric function plots of the real (ɛ1(ℏω)) and imaginary (ɛ2(ℏω)) parts show the anisotropic behavior of Hf2Al3C4 and Hf3Al3C5. The results on optical conductivity (σ) support the trends observed in dielectric functions. The electron energy loss functions reveal the presence of sharp peaks both in ab-plane and along c-axis around 20 eV in Hf2Al3C4 and Hf3Al3C5 ternary carbides.

Sensing behavior of acetone vapors on TiO2 nanostructures — application of density functional theory

The electronic properties of TiO$_2$ nanostructure are explored using density functional theory. The adsorption properties of acetone on TiO$_2$ nanostructure are studied in terms of adsorption energy, average energy gap variation and Mulliken charge transfer. The density of states spectrum and the band structure clearly reveals the adsorption of acetone on TiO$_2$ nanostructures. The variation in the energy gap and changes in the density of charge are observed upon adsorption of acetone on n-type TiO$_2$ base material. The results of DOS spectrum reveal that the transfer of electrons takes place between acetone vapor and TiO$_2$ base material. The findings show that the adsorption property of acetone is more favorable on TiO$_2$ nanostructure. Suitable adsorption sites of acetone on TiO$_2$ nanostructure are identified at atomistic level. From the results, it is confirmed that TiO$_2$ nanostructure can be efficiently utilized as a sensing element for the detection of acetone vapor in a mixed environment.

Analysis of triboelectric charging of particles due to aerodynamic dispersion by a pulse of pressurised air jet

Triboelectric charging of powders causes nuisance and electrostatic discharge hazards. It is highly desirable to develop a simple method for assessing the triboelectric charging tendency of powders using a very small quantity. We explore the use of aerodynamic dispersion by a pulse of pressurised air using the disperser of Morphologi G3asa novel application. In this device particles are dispersed by injection of a pulse of pressurised air, the dispersed particles are then analysed for size and shape analysis. The high transient air velocity inside the disperser causes collisions of sample particles with the walls, resulting in dispersion, but at the same time it could cause triboelectric charging of the particles. In this study, we analyse this process by evaluating the influence of the transient turbulent pulsed-air flow on particle impact on the walls and the resulting charge transfer. Computational Fluid Dynamics is used to calculate particle trajectory and impact velocity asa function of the inlet air pressure and particle size. Particle tracking is done using the Lagrangian approach and transient conditions. The charge transfer to particles is predicted asa function of impact velocity and number of collisions based on a charge transfer model established previously for several model particle materials. Particles experience around ten collisions at different velocities as they are dispersed and thereby acquire charges, the value of which approaches the equilibrium charge level. The number of collisions is found to be rather insensitive to particle size and pressure pulse, except for fine particles, smaller than about 30µm. As the particle size is increased, the impact velocity decreases, but the average charge transfer per particle increases, both very rapidly. Aerodynamic dispersion by a gas pressure pulse provides an easy and quick assessment of triboelectric charging tendency of powders.

Characteristics of the initial stage and return stroke currents of rocket‐triggered lightning flashes in southern China

AbstractThis study investigates the initial stage (IS) and return stroke (RS) currents of 50 triggered lightning flashes (TLFs) that were conducted in southern China. The IS of the negative TLFs has a longer duration and larger average current, charge transfer, and action integral than those reported elsewhere, with geometric means (GMs) of 347.9 ms, 132.5 A, 45.1 C, and 10.0 × 103 A2 s, respectively. Two positive TLFs containing no RS have much greater average currents, charge transfers, and action integrals in the IS when compared with the negative TLFs. The RS has a greater peak current (17.2 kA; GM, same to below), charge transfer within 1 ms (1.3 C), and action integral within 1 ms (5.8 × 103 A2 s), and shorter 10% to 90% rise time (0.4 μs) than elsewhere. The peak current is prominently correlated with the rate of rise, charge transfer within 1 ms, and action integral within 1 ms. Furthermore, when the total duration of the RS and any following continuing currents is longer than 40 ms, the peak current, charge transfer within 1 ms, and action integral within 1 ms of the RS are seldom greater than 25 kA, 2.6 C, and 15 × 103 A2 s, respectively. It is indicated that TLFs containing RSs tend to have a longer duration but a smaller charge transfer during the IS than those without RS. The peak current of the RS is weakly correlated with its preceding silence period when there was no channel base current.

Adhesion properties of Cu(111)/α-quartz (0001) interfaces: A molecular dynamics study

The fundamental properties of Cu/SiO2 interface are worth studying because they impact the quality and performance of silicon-based microelectronics and related devices. Using the charge-optimized many-body (COMB) potential in this study, we present a molecular dynamics simulation study of the structural, adhesive and electronic properties of Cu(111)/α-quartz SiO2 (0001) interfaces with two different crystalline orientations and various terminations by double-oxygens (OO), single-oxygen(O) and silicon(Si). For the equilibrated interfaces, the largest adhesion energies correspond to the oxygen richest OO-terminated interface in which the oxidation level of Cu is highest due to the largest charge transfer across the interface. In particular, we also investigate the properties of a series of nonequilibrated OO-, O- and Si-terminated interfaces that are created from their equilibrated counterparts by introducing vacancies of different numbers and different types. It is found that the adhesion energies of interfaces mostly decrease upon vacancy introductions only except for Si vacancies added in the Si-terminated interface. For all nonequilibrated interfaces of different terminations, we found a linear correlation between adhesive energy and area average excess charge transfer in Cu.

Borophene nanosheet molecular device for detection of ethanol – A first-principles study

The electronic and ethanol adsorption properties of hydrogenated 2D borophene nanosheet device are studied through non-equilibrium Green’s function (NEGF) and density functional theory (DFT) method. The adsorption property of ethanol on borophene nanosheet is investigated in terms of average energy gap variation, adsorption energy and Mulliken charge transfer. The variation in the density of states and energy band structure of ethanol adsorbed borophene nanosheet compared with its isolated borophene nanosheet clearly confirms the adsorption of ethanol molecule. The device density of states spectrum explains the variation in peak maxima owing to transfer of electrons between ethanol molecules and borophene base material. I-V characteristics support the variation in the current upon adsorption of ethanol molecules on the borophene molecular device. In order to verify the selectivity of ethanol molecules along borophene device in the ambient condition, the adsorption property of O2 is also studied. The findings confirm that borophene nanosheet can be used as an ethanol sensor.