Excess Charge Research Articles

Less is more: An oxyfluoride garnet broadband cyan-green phosphor towards highly efficient full-spectrum WLEDs

Full-spectrum lighting has become the development direction for human-centric illumination. However, the reabsorption effect caused by cyan, green and yellow multiple-phosphor packaging leads to low luminous efficiency. In this work, a broadband cyan-green phosphor is proposed to replace the cyan and yellow phosphors for highly efficient and thermally robust full-spectrum WLEDs. A new family of oxyfluoride garnet phosphors Lu2QMg2Al3O9F3: Ce3+ (Q = Ca, Sr, Ba) has been developed by incorporating F- into the classic LuAG: Ce3+ green phosphor. The excess charge was compensated by substituting trivalent Lu3+ and Al3+ with divalent alkaline earth element. The low covalency and phonon energy of fluorine-containing system endow these serial phosphors with efficient and thermally stable blue-shifted emission. The representative Lu2SrMg2Al3O9F3: Ce3+ exhibits a broadband cyan-green emission peaked at 513 nm with a 105 nm FWHM. Furthermore, outstanding quantum efficiency (88.4%) and thermal stability (94.3% @ 423 K) were achieved. This oxyfluoride phosphor was packaged with red phosphor without cyan phosphor on a blue chip. The obtained WLEDs show an excellent color rendering index (Ra = 96.8) with luminous efficiency (LE = 106 lm/W). This research might pave a promising avenue for the development of next-generation full-spectrum lighting.

X-rays, electrons, and neutrons as probes of atomic matter

X-rays, electrons, and neutrons probe different properties of matter. X-rays feel electron density (ED). Electrons sense the electrostatic potential (ESP) of electrons and nuclei. Neutrons are sensitive to nuclear coherent scattering length (NCSL). While NCSL maps are widely understood to be different, ED and ESP maps are tacitly assumed to be similar. Here, I show that the belief in ED and ESP map equivalence is mistaken, but contains a grain of truth. Using density functional theory (DFT), the Bethe-Mott (BM) relation, and the Thomas-Fermi (TF) and Cromer-Mann (CM) atomic models, I show that ED and ESP maps are indeed more similar to each other than to NCSL maps. Nevertheless, peak and integrated map values depend differently on the atomic order number and on the contributions from electrons in the inner and outer CM shells. ED and ESP maps also differ in the sign and relative magnitude of excess charge effects.

Janus molybdenum di-chalcogenides based van der Waals bilayers for supercapacitor electrode design- effects of interlayer stacking orientations on quantum capacitance

In this work, for the first time, the quantum capacitance of an artificial two-dimensional (2D) material system based on van der Waals (vdW) bilayer heterostructures of Janus Molybdenum Di-chalcogenides, MoXY (X≠Y, X/YS, Se, Te) have been extensively investigated for electrode design of electrical double-layer (EDL) supercapacitor. The effects of different interlayer stacking orientations on local charge distribution, interlayer charge transfer, energy band structure, and density of states (DOS) have been comprehensively analyzed and correlated with the excess charge density and quantum capacitance variation with local electrode potential. Furthermore, the total capacitance reduction with respect to EDL capacitance has been analyzed over a wide range of EDL capacitance, and the performance of vdW Janus bilayers has been systematically benchmarked against the natural monolayers/bilayers and Janus monolayers of Molybdenum Di-chalcogenides. The results demonstrate that the large interlayer charge transfer induced built-in interlayer electric field significantly reduces the energy band gap of vdW Janus bilayers for S–Te and Se–Te interlayer stacking, thus leading to a significantly superior quantum capacitance. Finally, the favorable valley-dependent effective mass and band-degeneracy in MoSTe/MoSeTe have greatly enhanced quantum capacitance in S–Te and Se–Te stacking, rendering these bilayers a highly attractive candidate for supercapacitor electrode design.

Observational features of charge distribution in Earth’s inner magnetosphere

Understanding the motion of charged particles in the electromagnetic field in the inner magnetosphere is essential for space science and space weather. Charge accumulation can occur due to the dipole magnetic and convective electric fields in this region. However, until the recent Magnetospheric Multiscale (MMS) mission, there were few means to detect charge distribution in situ. We report unambiguous in situ observation of the spatial distribution of the excess charge density in the inner magnetosphere by the MMS mission. We find that a positive (negative) charge accumulates in the dusk (dawn) side inner magnetospheres, which is contrary to the long assumed overall quasi-neutrality of space plasma. These observations and results offer insight into magnetosphere–ionosphere coupling.

Electron transfer-mediated synergistic nonlinear optical response in the Agn@C18 (n = 4–6) complexes: A DFT study on the electronic structures and optical characteristics

Seeking highly efficient and stable non-linear optical (NLO) materials is crucial yet challenging, given their promising applications in laser diodes and photovoltaics. In this study, we employ the excess electron and charge transfer strategies to theoretically design three novel complexes, namely Agn@C18 (n = 4–6), by adsorbing silver clusters onto the cyclo[18]carbon ring (C18). Our aim is to investigate the NLO characteristics of these complexes using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The results reveal that the adsorption of Ag clusters onto C18 leads to a decrease in excitation energy and an increase in dipole moment and oscillator strengths, thereby significantly enhancing the hyperpolarizability of the complexes. Strikingly, among all these complexes, Ag6@C18 exhibits the highest first hyperpolarizability value of approximately 109496.2620 au calculated at the B3LYP/cc-PVDZ-pp level of theory, which is about 1.3 × 106 times higher than that of pure C18. This finding validates the effectiveness of the proposed strategies in enhancing the NLO response of the species. Moreover, the calculated UV–Vis absorption spectrum demonstrates that the Agn@C18 complexes with excess electrons exhibit absorption at longer wavelengths (ranging from 385 to 731 nm) compared to C18. In addition, the stability, chemical bonding, and charge transfer characteristics of the Agn@C18 (n = 4–6) complexes were also discussed. These findings highlight the potential of these complexes for the development of highly efficient NLO devices.

A Novel Framework Interweaving in Mesoporous AlPO4 and Its Function in CO2 Decomposition

Molecular sieves are reported with isomorphous substitution by various metal ions. In this article, interweaving between tetrahedral framework of AlPO4 and the octahedral framework of CoO to produce a novel framework material is investigated; it is named as “Kankarlite” (CoO–AlPO4‐4). It is characterized by X‐ray diffraction (XRD), Fourier transform infrared, Brunauer–Emmett–Teller (BET), UV‐Vis analysis, thermogravimetric analysis (TGA), temperature programmed desorption (TPD) analysis, and transmission electron microscopy. The special feature of the catalyst is that it has two frameworks that are interweaved together to form a novel framework, which is proved by XRD and the crystal structure is drawn by VESTA software. In CoO framework, oxygen has three coordinations, which is proved by crystal structure. An excess negative charge appears on oxygen, creating an oxyanion. The TPD is also proved the oxyanion formation. This oxyanion is responsible for decomposing CO2 with high selectivity and conversion. The AlPO4 framework's function is to create mesopores in the catalyst. The TGA and UV‐Vis analyses prove the interweaving between two frameworks. The BET analysis proves that the Kankarlite has a pore size of 4 nm.

Accelerated Degradation of FAPbI3 Perovskite by Excess Charge Carriers and Humidity

Excess charge carriers in metal halide perovskite layer have been known to accelerate degradation of the film and devices to cause poor operational stability of perovskite solar cells (PSCs). While mechanisms for such degradation have been predominantly studied for methylammonium‐based perovskites, effects of excess charge carriers and their interplays with other degradation causes are barely studied for widely used formamidinium‐based perovskites. Herein, a possible decomposition mechanism of the formamidinium lead tri‐iodide (FAPbI3) perovskite in the presence of excess charge under different humidity levels is investigated. The operating condition with excessive charges is simulated by placing half devices with either electron‐transporting layer (ETL) or hole‐transporting layer (HTL) under 1 sun illumination. FAPbI3 in contact with ETL degrades more rapidly than the one with HTL, which is attributed to excess hole charge carriers in the film. Under higher humidity, the synergetic effect of excess charge carriers and humidity is found and thus degradation pathway and kinetics are strongly dependent on the humidity level. The fundamental understanding of degradation pathways for formamidinium perovskites should provide a useful insight toward the development of efficient and operationally stable PSCs toward practical usage.

Electrical environment can be altered at 1 km distances from high voltage power lines.

High voltage powerlines emit electrical charges into the atmosphere which can then attach to aerosols. This space charge above ground can be measured directly using ion spectrometers or indirectly through perturbations of the Earth’s potential gradient using field mills. Several publications are reviewed to find evidence of aerosol charging at a distance from power lines. Field measurements of charge state near to high voltage power lines selected due to their high emissions of ions measured a small positive enhancement of electrical charge on aerosols at distances greater than 300 m, corresponding to a transit time of up to 400 s A quasi one-dimensional model of ion-aerosol interactions from a high voltage powerlines found that the addition of new ions to an aerosol population will result in those ions transferring charge to the aerosol which would then remain the dominant carrier of charge several hundred meters downwind. 10-min PG measurements from a fixed site measuring in 2008 compared measurements when the site was downwind of a 275 kV powerline to times with no wind and found evidence of space charge overhead through greater fields and variability at distances over 800 m These studies combined show evidence that the electrical environment near to power lines can be altered beyond 1 km from AC high voltage power lines, with excess charges likely to be concentrated on aerosol.

Local electroneutrality breakdown for electrolytes within varying-section nanopores

We determine the local charge dynamics of a z-z\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$z-z$$\\end{document} electrolyte embedded in a varying-section channel. By means of an expansion based on the length scale separation between the axial and transverse direction of the channel, we derive closed formulas for the local excess charge for both, dielectric and conducting walls, in 2D (planar geometry) as well as in 3D (cylindrical geometry). Our results show that, even at equilibrium, the local charge electroneutrality is broken whenever the section of the channel is not homogeneous for both dielectric and conducting walls as well as for 2D and 3D channels. Interestingly, even within our expansion, the local excess charge in the fluid can be comparable to the net charge on the walls. We critically discuss the onset of such local electroneutrality breakdown in particular with respect to the correction that it induces on the effective free energy profile experienced by tracer ions.Graphical abstract

First experimental evaluation of a high-resolution deep silicon photon-counting sensor.

Current photon-counting computed tomography detectors are limited to a pixel size of around 0.3 to 0.5mm due to excessive charge sharing degrading the dose efficiency and energy resolution as the pixels become smaller. In this work, we present measurements of a prototype photon-counting detector that leverages the charge sharing to reach a theoretical sub-pixel resolution in the order of . The goal of the study is to validate our Monte-Carlo simulation using measurements, enabling further development. We measure the channel response at the MAX IV Lab, in the DanMAX beamline, with a 35keV photon beam, and compare the measurements with a 2D Monte Carlo simulation combined with a charge transport model. Only a few channels on the prototype are connected to keep the number of wire bonds low. The measurements agree generally well with the simulations with the beam close to the electrodes but diverge as the beam is moved further away. The induced charge cloud signals also seem to increase linearly as the beam is moved away from the electrodes. The agreement between measurements and simulations indicates that the Monte-Carlo simulation can accurately model the channel response of the detector with the photon interactions close to the electrodes, which indicates that the unconnected electrodes introduce unwanted effects that need to be further explored. With the same Monte-Carlo simulation previously indicating a resolution of around with similar geometry, the results are promising that an ultra-high resolution detector is not far in the future.

Effective interception of redox mediator shuttle behavior for Li[sbnd]O2 battery by separator modification based on g-C3N4 doped with Co elements

The utilization of redox mediators (RMs) offers a promising solution to address the issue of excessive charging voltage resulting from the generation of lithium peroxide (Li2O2) at the cathode in lithium‑oxygen (LiO2) batteries. However, the effectiveness of RMs is significantly impeded by a crucial drawback commonly referred to as the “shuttle phenomenon.” This phenomenon involves the RMs not only participating in the decomposition of Li2O2 but also migrating to the anode, where it reacts with the Li metal. Consequently, the RMs experience inevitable degradation, resulting in a severely limited cycling life. To tackle this challenge, we propose a strategy on limiting the 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) worked as RM to the cathodic side by modifying the separator with the g-C3N4 doping with Co (Co-C3N4). Through the adsorption of TEMPO onto the Co-C3N4, the modified separator efficiently captures the TEMPO thus suppresses the shuttle effect. As a result, the Li metal anode is effectively safeguarded, facilitating uninterrupted and prolonged operation of the rechargeable battery. A remarkable cycle life of up to 160 cycles for LiO2 batteries can be realized, thus demonstrating the successful implementation of our strategy.

Trends in Hospital Billing for Mastectomy and Breast Reconstruction Procedures from 2013 to 2020.

With greater acceptance of postmastectomy breast reconstruction (PMBR) as a safe and reliable treatment option, the role of plastic surgeons in breast cancer management continues to rise. As Medicare reimbursements for surgical procedures decline, hospitals may increase charges. Excessive markups can negatively affect uninsured and underinsured patients. We aimed to analyze mastectomy and breast reconstruction procedures to gain insights into recent trends in utilization and billing. We queried the 2013 to 2020 Medicare Provider Utilization and Payment Data with 14 Current Procedural Terminology (CPT) codes to collect service count numbers, hospital charges, and reimbursements. We calculated utilization (service counts per million female Medicare enrollees), weighted mean charges and reimbursements, and charge-to-reimbursement ratios (CRRs). We calculated total and annual percentage changes for the included CPT codes. Among the 14 CPT codes, 12 CPT codes (85.7%) with nonzero service counts were included. Utilization of mastectomy and breast reconstruction procedures decreased from 1,889 to 1,288 (-31.8%) procedures per million female Medicare beneficiaries from 2013 to 2020. While the utilization of immediate implant placements (CPT 19340) increased by 36.2%, the utilization of delayed implant placements (CPT 19342) decreased by 15.1%. Reimbursements for the included CPT codes changed minimally over time (-2.9%) but charges increased by 28.9%. These changes resulted in CRRs increasing from 3.3 to 4.4 (+33.3%) from 2013 to 2020. Free flap reconstructions (CPT 19364) had the highest CRRs throughout the study period, increasing from 7.0 in 2013 to 10.3 in 2020 (+47.1%). Our analysis of mastectomy and breast reconstruction procedures billed to Medicare Part B from 2013 to 2020 showed increasingly excessive procedural charges. Rises in hospital charges and CRRs may limit uninsured and underinsured patients from accessing necessary care for breast cancer management. Legislations that monitor hospital markups for PMBR procedures may be considered by policymakers.

Atomistic origin of high grain boundary resistance in solid electrolyte lanthanum lithium titanate

Lanthanum lithium titanate is one of the promising electrolytes for solid-state lithium-ion batteries due to its high bulk ionic conductivity up to ∼10−3 S/cm. However, the practical application of this material has been bottlenecked by high grain boundary (GB) resistance, while the underlying mechanism is still under debate. Here we report a comprehensive study with direct evidence to reveal the origin of high GB resistance in La2/3–xLi3xTiO3 (LLTO). Atomic-scale observations via advanced scanning transmission electron microscopy show that the GBs are uniformly subject to subsurface segregation of La atoms to compensate for the excess surface charges. The La segregation leads to an abrupt decrease of charge carrier concentration neighboring GBs and hence is supposed to have deleterious effect on GB conductivity. The findings suggest a novel mechanism of space-charge-induced cation segregation, which shed lights on the intrinsic origin of low GB ionic conductivity in LLTO.

From Jekyll to Hyde and Beyond: Hydrogen's Multifaceted Role in Passivation, H-Induced Breakdown, and Charging of Amorphous Silicon Nitride.

In semiconductor devices, hydrogen has traditionally been viewed as a panacea for defects, being adept at neutralizing dangling bonds and consequently purging the related states from the band gap. With amorphous silicon nitride (a-Si3N4)─a material critical for electronic, optical, and mechanical applications─this belief holds true as hydrogen passivates both silicon and nitrogen dangling bonds. However, there is more to the story. Our density functional theory calculations unveil hydrogen's multifaceted role upon incorporation in a-Si3N4. On the "Jekyll" side, hydrogen atoms are indeed restorative, healing coordination defects in a-Si3N4. However, "Hyde" emerges as hydrogen induces Si-N bond breaking, particularly in strained regions of the amorphous network. Beyond these dual roles, our study reveals an intricate balance between hydrogen defect centers and intrinsic charge traps that already exist in pristine a-Si3N4: the excess charges provided by the H atoms result in charging of the a-Si3N4 dielectric layer.

Legal Interest’s Pivotal Role in Ensuring the Fulfillment of the Obligation

The present study aims to highlight the issue of legal interest within the Jordanian legal framework and the extent of its compatibility with human rights considerations. It explores the various sources of legal interest, including the Jordanian Civil Law, the Ottoman Murabaha system, the Central Bank Law, the Jordanian Code of Procedure, and the Jordanian Trade Law. The study examines the absence of an explicit provision on legal interest in the Jordanian Civil Code and emphasizes the need for its inclusion. The study reveals that while legal interest is allowed in principle, there is no explicit provision in the Jordanian Civil Code. The research findings emphasize the need for an explicit provision in the Civil Code to regulate legal interest, granting discretionary authority to the court while ensuring it does not exceed the maximum limit of 9%. This approach would prevent excessive interest charges, promote fairness, and address potential exploitation. The recommendation seeks to organize legal interest provisions in a detailed and precise manner to ensure clarity and protect the rights of the parties involved. The researcher recommends granting discretionary authority to the court to estimate legal interest within the limit of 9%.

Unveiling the Borohydride Ion through Force-Field Development.

The borohydride ion, BH4-, is an essential reducing agent in many technological processes, yet its full understanding has been elusive, because of at least two significant challenges. One challenge arises from its marginal stability in aqueous solutions outside of basic pH conditions, which considerably limits the experimental thermodynamic data. The other challenge comes from its unique and atypical hydration shell, stemming from the negative excess charge on its hydrogen atoms, which complicates the accurate modeling in classical atomistic simulations. In this study, we combine experimental and computer simulation techniques to devise a classical force field for NaBH4 and deepen our understanding of its characteristics. We report the first measurement of the ion's activity coefficient and extrapolate it to neutral pH conditions. Given the difficulties in directly measuring its solvation free energies, owing to its instability, we resort to quantum chemistry calculations. This combined strategy allows us to derive a set of nonpolarizable force-field parameters for the borohydride ion for classical molecular dynamics simulations. The derived force field simultaneously captures the solvation free energy, the hydration structure, as well as the activity coefficient of NaBH4 salt across a broad concentration range. The obtained insights into the hydration shell of the BH4- ion are crucial for accurately modeling and understanding its interactions with other molecules, ions, materials, and interfaces.

Enhancing the safety and effectiveness of polyethylenimine gene delivery through cell membrane encapsulation

Due to the powerful DNA loading capacity and excellent proton sponge effect, the cationic polymer polyethyleneimine (PEI) has been demonstrated as a versatile, efficient DNA delivery tool both in vitro and in vivo. However, the excess surface positive charge of PEI and the common capture/clearance of PEI/DNA complex by the immune system limit its further clinical applications. To reduce the cytotoxicity resulting from surface charge and avoid the clearance of nanoparticles interacting with proteins and circulating immune cells in the blood, a bionic gene delivery system was developed by coating PEI/DNA complexes with natural cell membranes. The obtained RAW Cell membrane-coated PEI/DNA capsules (RAWm-PDc) and Red blood Cell membrane-coated PEI/DNA capsules (RBCm-PDc) complex showed excellent dispersibility and stability with an average particle size of 200–300 nm. Moreover, the RAWm-PDc/RBCm-PDc complex had great DNA loading capacity and protected the bound DNA effectively from nuclease hydrolysis. Most importantly, the RAWm-PDc/RBCm-PDc complex exhibited low protein adsorption, reduced cytotoxicity and high gene delivery efficiency. All the results demonstrated the potential of RAWm-PDc/RBCm-PDc as a promising non-viral gene delivery vector.

Infrared Nanoimaging of Hydrogenated Perovskite Nickelate Memristive Devices.

Solid-state devices made from correlated oxides, such as perovskite nickelates, are promising for neuromorphic computing by mimicking biological synaptic function. However, comprehending dopant action at the nanoscale poses a formidable challenge to understanding the elementary mechanisms involved. Here, we perform operando infrared nanoimaging of hydrogen-doped correlated perovskite, neodymium nickel oxide (H-NdNiO3, H-NNO), devices and reveal how an applied field perturbs dopant distribution at the nanoscale. This perturbation leads to stripe phases of varying conductivity perpendicular to the applied field, which define the macroscale electrical characteristics of the devices. Hyperspectral nano-FTIR imaging in conjunction with density functional theory calculations unveils a real-space map of multiple vibrational states of H-NNO associated with OH stretching modes and their dependence on the dopant concentration. Moreover, the localization of excess charges induces an out-of-plane lattice expansion in NNO which was confirmed by in situ X-ray diffraction and creates a strain that acts as a barrier against further diffusion. Our results and the techniques presented here hold great potential for the rapidly growing field of memristors and neuromorphic devices wherein nanoscale ion motion is fundamentally responsible for function.

Ultrasensitive detection of ornidazole–antibiotic drug residues in water using NiMOFs functionalized MWCNT modified electrode

Nitroimidazole-based drugs are widely used as an antibiotic for the treatment of anaerobic bacterial and parasite illnesses. The widespread use of these drugs in animal feed and the consequent environmental pollution have become significant concerns in recent years. Simple, sensitive, and rapid detection of the antibody in various real samples is demanding research interest. Herein, we report a Nickel-metal organic framework functionalized Multiwalled Carbon nanotubes modified glassy carbon electrode (MWCNT@NiMOFs) as an ultrasensitive and rapid voltammetric sensor for the detection of ornidazole (ORDZ) in a neutral pH solution. The MWCNT@NiMOFs were prepared using a microwave-assisted solvothermal technique accompanied by an ultrasonication method. The designed MWCNT@NiMOFs offered a low charge transfer resistance (Rct) of 141 Ω along with excellent electrocatalytic activity, and high current density at the lowered cathodic peak potential (-0.62 V vs Ag/AgCl) for ORDZ detection. The surface adsorption capacity (Γs) in terms of surface excess and heterogeneous charge transfer rate constant (k0) of the MWCNT@NiMOFs were calculated to be 3.29 × 10-9 mol cm−2 and 5.33 × 10-3 cm s−1, respectively. Under an optimal working condition, differential pulse voltammetry measurements of ORDZ have shown concentration linearity in a window, 100 nm to 10 µM range with excellent sensitivity, 5.69 × 10-5A µM−1 cm−2, and detection limit, 26 nM (3.3/s). The designed MWCNT@NiMOFs offered appreciable reproducibility, and repeatability up to 30 days of storage time. The real-time quantitative evaluation of ORDZ in human urine and tap water specimens was done along with ∼ 100 % recovery values. Since the new approach is simple, selective, and separation-free, it can be extendable to a variety of real-time practical applications.

Two strain modes and transition point of 18650 lithium-ion battery at different charging rates

The safety issues of lithium-ion batteries are one of the biggest obstacles restricting the development of lithium-ion batteries. Excessive charging rate is not conducive to extending the cycle life of lithium-ion batteries. However, there is a lack of research on the upper limit of the charging rate of lithium batteries. The strain of the battery can reflect the change of the internal material during the charging process. The purpose of this study is to explore the charging rate of the strain transition point of lithium-ion batteries and the strain characteristics of the batteries after exceeding this rate. The experiments conducted at different rates and temperatures on battery strain revealed that the transition point of strain in the battery occurs at a rate of 2C. When the charging rate is lower than 2C, the battery strain increases monotonically, which is similar to the step response of the first-order system. When the charging rate exceeds 2C, the battery strain experiences excessive strain due to severe lithium plating, showing a step response similar to a second-order system with a spike representing an overshoot phenomenon. As the charging rate continues to increase, the overshoot peak of the battery ‘s strain becomes more obvious. The experimental results confirm that the charging rate of the 18,650 ternary lithium-ion battery used in the experiment should not exceed 2C, as it would lead to excessive strain in the battery.