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Granular metals (GMs), consisting of metal nanoparticles separated by an insulating matrix, frequently serve as a platform for fundamental electron transport studies. However, few technologically mature devices incorporating GMs have been realized, in large part because intrinsic defects (e.g., electron trapping sites and metal/insulator interfacial defects) frequently impede electron transport, particularly in GMs that do not contain noble metals. Here, we demonstrate that such defects can be minimized in molybdenum–silicon nitride (Mo–SiNx) GMs via optimization of the sputter deposition atmosphere. For Mo–SiNx GMs deposited in a mixed Ar/N2 environment, x-ray photoemission spectroscopy shows a 40%–60% reduction of interfacial Mo-silicide defects compared to Mo–SiNx GMs sputtered in a pure Ar environment. Electron transport measurements confirm the reduced defect density; the dc conductivity improved (decreased) by 104–105 and the activation energy for variable-range hopping increased 10×. Since GMs are disordered materials, the GM nanostructure should, theoretically, support a universal power law (UPL) response; in practice, that response is generally overwhelmed by resistive (defective) transport. Here, the defect-minimized Mo–SiNx GMs display a superlinear UPL response, which we quantify as the ratio of the conductivity at 1 MHz to that at dc, Δ σ ω. Remarkably, these GMs display a Δ σ ω up to 107, a three-orders-of-magnitude improved response than previously reported for GMs. By enabling high-performance electric transport with a non-noble metal GM, this work represents an important step toward both new fundamental UPL research and scalable, mature GM device applications. [ABSTRACT FROM AUTHOR]

The structural parameters, electron localization functions, electron paramagnetic resonance (EPR) parameters, formation energies, and thermodynamic transition levels of various oxygen vacancy defects in amorphous silica are comprehensively and integrally investigated by using density functional theory. The trends of changes in the oxygen vacancy defect structure and electron localization induced by the increase in distance between defective silicon atoms are clearly identified. It is shown that the dimer configuration may be the potential structure of the E δ ′ center. For the back-projected unpuckered configuration and the puckered configuration, whose EPR parameters are more consistent with the experimental values of the E γ ′ center, the unpaired electron localized on the sp3 hybridized silicon atom is a common feature. Due to the three-coordinated oxygen atom in the forward-oriented configuration, the EPR parameters are closest to those of the E α ′ center. Transformations of oxygen vacancy defects under different charge states are studied by sequentially adding and removing electrons. The thermodynamic transition level analysis reveals that the dimer and forward configurations may behave as deep traps for electron accumulation. The back-projected puckered fourfold-coordinated and fivefold-coordinated configurations are comparatively stable and may be able to function as shallow traps for electron transport. The neutral double unpuckered, neutral back-projected puckered fourfold-coordinated, and neutral back-projected unpuckered configurations are more likely to lose electrons during hole trapping. As the bias voltage is repeatedly changed, the defect density of the puckered configuration may reduce, while that of the dimer and unpuckered configuration may take an opposite trend. [ABSTRACT FROM AUTHOR]

Noting that the conventional collision-dominated electron transport perspective is only relevant when the length scale over which the transit occurs is greater than the electron's mean free path, one can conceptually partition the electron transport "space" into collision-dominated and ballistic electron transport regimes. As the boundaries between these regimes are quite porous, in this analysis, we devise a means of quantitatively examining the transition between electron transport regimes as the length scale is reduced on a continuum basis. Our approach introduces a collision-dominated fractional scattering parameter, this parameter quantifying the fraction of the total scattering rate that arises purely from bulk scattering processes, contact scattering also contributing to the total scattering rate. We pursue this analysis for two conventional semiconductors of interest, silicon and gallium arsenide. A determination of the dependence of the results on both the length scale and the crystal temperature is pursued. Finally, for the specific case of room temperature, a comparison with the results of experiment is performed. [ABSTRACT FROM AUTHOR]

In this manuscript, carrier transport simulation methods are proposed for devices with the coexistence of quantum transport and diffusive transport by combining the nonequilibrium Green's function method with the drift-diffusion transport simulation method. Current continuity between quantum transport and drift-diffusion transport is ensured by setting quantum transport current as the connection boundary condition of drift-diffusion simulation or by introducing quantum transport-induced carrier generation rates to drift-diffusion simulation. A comprehensive study of our method and the method combining the Wentzel–Kramers–Brillouin (WKB) method with the drift-diffusion transport simulation method is performed for n-type tunnel oxide passivating contact solar cell to investigate their applicable conditions and balance the accuracy and computational cost. As the oxide barrier width, barrier height, and electron effective mass increase, or the doping concentration in the electron transport layer decreases to the extent that the blocking effect of the oxide barrier on light-generated electrons becomes significant, method I is more accurate since the transmission coefficient near the conduction band edge calculated by WKB is overestimated; otherwise, method II is more suitable due to its low computational cost without the loss of accuracy. In addition, the differences between current densities, carrier densities, and Shockley–Read–Hall recombination rates simulated under the two current continuity conditions for the solar cell with different carrier mobilities are also further explored and analyzed. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have demonstrated exceptional development over the past decade, but their stability remains a challenge toward the application of this technology. Several strategies have been used to address this, and the use of host–guest complexation has recently attracted more interest. However, this approach has primarily been exploited in conventional perovskite solar cells based on n-i-p architectures, while its use in inverted p-i-n devices remains unexplored. Herein, we employ representative crown ether, dibenzo-24-crown-8, for interfacial host–guest complexation in inverted perovskite solar cells based on methylammonium and methylammonium-free formamidinium-cesium halide perovskite compositions. Upon post-treatment of the perovskite films, we observed nanostructures on the surface that were associated with the reduced amount of trap states at the interface with the electron transport layer. As a result, we demonstrate improved efficiencies and operational stabilities following ISOS-D-2I and ISOS-L-2I protocols, demonstrating the viability of this approach to advance device stability. [ABSTRACT FROM AUTHOR]

Porous, stacked two-dimensional covalent organic frameworks (2D COFs) bearing semiconducting linkers can support directional charge transfer across adjacent layers of the COF. To better inform the current and possible future design rules for enhancing electron and hole transport in such materials, an understanding of how linker selection and functionalization affects interlayer electronic couplings is essential. We report electronic structure simulation and analysis of electronic couplings across adjacent linker units and to encapsulated species in functionalized electroactive 2D COFs. The detailed dependence of these electronic couplings on interlayer interactions is examined through scans along key interlayer degrees of freedom and through configurational sampling from equilibrium molecular dynamics on semiempirical potential energy surfaces. Beyond affirming the sensitivity of the electronic coupling to interlayer distance and orientation, these studies offer guidance toward linker functionalization strategies for enhancing charge carrier transport in electroactive 2D COFs. [ABSTRACT FROM AUTHOR]

A generalized quantum master equation approach is introduced to describe electron transfer in molecular junctions that spans both the off-resonant (tunneling) and resonant (hopping) transport regimes. The model builds on prior insights from scattering theory but is not limited to a certain parameter range with regard to the strength of the molecule–electrode coupling. The framework is used to study the simplest case of energy and charge transfer between the molecule and the electrodes for a single site noninteracting Anderson model in the limit of symmetric and asymmetric coupling between the molecule and the electrodes. In the limit of elastic transport, the Landauer result is recovered for the current by invoking a single active electron Ansatz and a binary collision approximation for the memory kernel. Inelastic transport is considered by allowing the excitation of electron–hole pairs in the electrodes in tandem with charge transport. In the case of low bias voltages where the Fermi levels of the electrodes remain below the molecular state, it is shown that the current arises from tunneling and the molecule remains neutral. However, once the threshold is reached for aligning the fermi level of one electrode with the molecular orbital, a small amount of charge transfer occurs with a negligible amount of hopping current. While inelasticity in the current has a minimal impact on the shape of the current–voltage curve in the case of symmetric electrode coupling, the results for a slight asymmetry in coupling demonstrate complete charge transfer and a significant drop in current. These results provide encouraging confirmation that the framework can describe charge transport across a wide range of electrode–molecule coupling and provide a unique perspective for developing new master equation treatments for energy and charge transport in molecular junctions. An extension of this work to account for inelastic scattering from electron–vibrational coupling at the molecule is straightforward and will be the subject of subsequent work. [ABSTRACT FROM AUTHOR]

The photochromic behavior of the fulgide molecule relies on ring-closure and ring-opening processes involving conical intersections during excited state transformation between isomers. The precise location and topography of these conical intersections significantly shape the decay process and fluorescence phenomena inherent to the molecule. This work combines electronic structure theory calculations using the density functional theory and wavefunction methods, as well as surface hopping simulation to analyze the photochemical behavior of an experimentally synthesized fulgide molecule, (E)-p-methylacetophenylisopropylidenesuccinic anhydride (1E). Our study reveals the conical intersection between the first excited state (S1) and the ground electronic state (S0), which emerges beyond the S1 minimum of 1E to the ring-closing side. The distinctive topography of this conical intersection appears to be sloped. These findings suggest a reduced quantum yield for the formation of the closed isomer, indicating a higher likelihood of reformation of the open isomer(s). The surface hopping simulation further supports this observation, revealing a mere ∼8% quantum yield for the formation of the closed isomer. In addition, the photoisomerization of the fulgide molecule initiates a cascade of conduction switching and holds great potential for applications in molecular electronics. Delving into the realm of molecular electronics, we have further examined the electron transport properties, disclosing the higher conductivity of the closed isomer. [ABSTRACT FROM AUTHOR]

Current–voltage characteristics, space- and time-resolved optical emission spectroscopy, and 1D fluid modeling are used to examine the effect of dual-frequency sheath oscillations on the ion and electron transport in dielectric barrier discharges sustained by a combination of low frequency (LF, 50 kHz, 650 V) and radiofrequency (RF, 5.3 MHz, 195 V) voltages, exhibiting the α-to-γ mode transition. On one hand, when polarities of the LF and RF voltages are opposite, an electric field near the LF cathode (due to LF cathode sheath) drives the secondary electrons to the plasma bulk and an opposite electric field between the sheath edge and the LF anode attracts the electrons toward the LF cathode (to maintain quasi-neutrality in the plasma bulk). At the sheath edge, electrons become trapped and ions drift toward the cathode and the anode simultaneously according to their position in the gap. On the other hand, when the RF voltage has the same polarity as the LF voltage, the total applied voltage increases and this yields to enhanced production of electrons and ions in the sheath. To maintain quasi-neutrality in the bulk, the electric field along the gap exhibits the same polarity as the one in the sheath, allowing electrons created in the sheath to be evacuated toward the LF anode. The behavior of the LF cathode is, therefore, controlled by the LF sheath, and, thus, by the LF voltage amplitude, while the behavior in the bulk and at the anode alternates on the time scale of the RF voltage. [ABSTRACT FROM AUTHOR]

Efficient thermoelectric energy conversion at the nanoscale could power the Internet of Things and cool nanoelectronic circuits and improve the performance of quantum applications. Width-modulated nanowaveguides are suitable for these purposes because their thermoelectric efficiency can be geometrically tuned and integrated into the nanoelectronics industry processes. They are attracting increasing research interest stimulated by theoretical predictions for exceptional performance. To validate their potential, a better understanding of the effect of width modulation on thermoelectric efficiency is needed. So far, it is considered that (a) the thermoelectric efficiency increases monotonically with increasing width-mismatch due to decreasing phonon thermal conduction taking place without significantly affecting electron transport, (b) width-mismatch dominates the effect of width modulation in transport, and (c) phonons play the main role in increasing the thermoelectric efficiency. Here, we demonstrate counterevidence based on an investigation of the effect of width modulation on electrons so far overlooked. We reveal that (a) the thermoelectric efficiency varies non-monotonically with the modulation mismatch due to quantum effects on electron transport, (b) the modulation mismatch is quantified by the size-mismatch of the modulation rather than by the width-mismatch, and (c) it is electrons rather than phonons that play the main role in optimizing width modulation for maximum thermoelectric efficiency when quantum effects dominate. Our findings indicate that research should reorient from large width-mismatch toward optimal modulation-mismatch width-modulated nanostructures to enhance thermoelectric efficiency due to quantum effects. Our work provides new insight for designing nanowaveguides for efficient thermoelectric energy conversion at the nanoscale. [ABSTRACT FROM AUTHOR]

Electron emission and transport through and over potential barriers is an essential process requiring modeling and simulation to meet the design needs and characterization of an exceedingly broad range of technologically important devices and processes. The simulation and description of thermal, field, and photoemission, and the related concerns of space–charge affected electron flow, often make use of specialized formulations developed in the early days of quantum mechanics. Advancements in the utilization of electron sources and particularly the simulation of devices and applications using advanced particle-in-cell and trajectory methods for beam optics codes create a strong need for a pedagogical account of the emission models to ensure correct numerical evaluation of their equations. This Tutorial starts from simple phenomenological accounts and progressively builds to comprehensive models emphasizing straightforward and often rapid calculation. It recommends formulations to supplant the canonical Richardson–Laue–Dushman (thermal), Fowler–Nordheim (field), Fowler–DuBridge (photo), and Baroody (secondary) equations and provides a useful formulation of space–charge affected flow commonly described by the Child–Langmuir relation that takes into account cathode dependence on surface field. [ABSTRACT FROM AUTHOR]

We report on the study of electron transport and band offset across β -Ga 2 O 3 /4H-SiC N–n isotype heterojunction. N-type β -Ga 2 O 3 of thickness 2.7 μ m was grown using low-pressure chemical vapor deposition using germanium (Ge) as the dopant on an n-type 4H-SiC substrate. The grown epilayer having (− 201) orientation was verified through XRD. Temperature-dependent I–V and C–V measurements were performed (50–300 K) to investigate the transport properties across the heterojunction. First, lateral diodes were fabricated on β -Ga 2 O 3 , and from C–V, n-doping was estimated to be 2.3 × 10 17 cm − 3 in the epilayer while the Schottky barrier height was estimated to be 1.75 eV. In top-down I–V sweeps, the reverse current across the heterojunction exhibited marginal dependence on temperature, indicating a possible tunnelling-based transport mechanism, while the forward current exhibited an exponential dependence on both temperature and the applied bias. The band diagram indicated the formation of a two-dimensional electron gas (2DEG) at the hetero-interface, which was indirectly confirmed using C–V measurement and TCAD simulation at low temperatures. From the position of the Fermi level in SiC and band diagram, a conduction band offset of 0.4–0.5 eV was estimated between β -Ga 2 O 3 and 4H-SiC. [ABSTRACT FROM AUTHOR]

In recent years, organic–inorganic hybrid perovskite (PVK) devices have attracted widespread attention with their high absorption coefficient and low-cost fabrication process. Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) have been reported to obtain high power conversion efficiencies (PCEs) due to the narrow bandgap. Zinc oxide (ZnO) has better electrical conductivity and high transmittance than tin (IV) dioxide (SnO2). However, the deprotonation behavior of ZnO limits its use in formamidinium (FA) or methylammonium (MA) devices, so it is mostly used in all-inorganic PSCs. In this work, to avoid the deprotonation behavior of ZnO, we prepared FAPbI3 PSCs using ZnO/SnO2 as bilayer electron transporting layers (ETLs), which improved the conductivity of the ETLs and promoted electron extraction and transfer. In addition, the decrease in the oxygen vacancy (Ov) on the bilayer ETLs contributed to the suppression of the non-radiative recombination of the device, thus enabling the achievement of a higher fill factor. As a result, the modified ETLs increased the PCE of FAPbI3 PSCs from 20.24% to 21.42% and improved the stability of the devices. The PCE of unpackaged devices increased steadily to 21.91% when stored in an N2 atmosphere for 183 days. [ABSTRACT FROM AUTHOR]

Methanogens are a diverse group of Archaea that obligately couple energy conservation to the production of methane. Some methanogens encode alternate pathways for energy conservation, like anaerobic respiration, but the biochemical details of this process are unknown. We show that a multiheme c-type cytochrome called MmcA from Methanosarcina acetivorans is important for intracellular electron transport during methanogenesis and can also reduce extracellular electron acceptors like soluble Fe3+ and anthraquinone-2,6-disulfonate. Consistent with these observations, MmcA displays reversible redox features ranging from -100 to -450 mV versus SHE. Additionally, mutants lacking mmcA have significantly slower Fe3+ reduction rates. The mmcA locus is prevalent in members of the Order Methanosarcinales and is a part of a distinct clade of multiheme cytochromes that are closely related to octaheme tetrathionate reductases. Taken together, MmcA might act as an electron conduit that can potentially support a variety of energy conservation strategies that extend beyond methanogenesis.

Rutile-type wide and ultrawide band-gap oxide semiconductors are emerging materials for high-power electronics and deep ultraviolet optoelectronics applications. A rutile-type GeO2-SnO2 alloy (r-GexSn1–xO2) recently found is one of such materials. Herein, we report low-temperature electron transport properties of r-GexSn1−xO2 thin films with x = 0.28 and 0.41. Based on resistivity and magnetoresistance measurements, along with the theory of quantum interference, it is suggested that Efros–Shklovskii variable-range hopping, i.e., hopping over the states within the Coulomb gap, is dominant at lower temperatures (T ≤ 10 and 15 K) in both r-Ge0.41Sn0.59O2 and r-Ge0.28Sn0.72O2. The negative and positive magnetoresistances observed at low temperatures are attributable to the quantum interference and field-induced spin alignment, respectively. The magnetoresistance measurements at higher temperatures suggest that both Mott variable–range hopping and thermally activated band conduction occur at T < 100 K and that almost pure thermally activated band conduction takes place at T ≥ 150 K. [ABSTRACT FROM AUTHOR]

Rutile-type wide and ultrawide band-gap oxide semiconductors are emerging materials for high-power electronics and deep ultraviolet optoelectronics applications. A rutile-type GeO2-SnO2 alloy (r-GexSn1–xO2) recently found is one of such materials. Herein, we report low-temperature electron transport properties of r-GexSn1−xO2 thin films with x = 0.28 and 0.41. Based on resistivity and magnetoresistance measurements, along with the theory of quantum interference, it is suggested that Efros–Shklovskii variable-range hopping, i.e., hopping over the states within the Coulomb gap, is dominant at lower temperatures (T ≤ 10 and 15 K) in both r-Ge0.41Sn0.59O2 and r-Ge0.28Sn0.72O2. The negative and positive magnetoresistances observed at low temperatures are attributable to the quantum interference and field-induced spin alignment, respectively. The magnetoresistance measurements at higher temperatures suggest that both Mott variable–range hopping and thermally activated band conduction occur at T < 100 K and that almost pure thermally activated band conduction takes place at T ≥ 150 K. [ABSTRACT FROM AUTHOR]

Metal-reducing bacteria have adapted the ability to respire extracellular solid surfaces instead of soluble oxidants. This process requires an electron transport pathway that spans from the inner membrane, across the periplasm, through the outer membrane, and to an external surface. Multiheme cytochromes are the primary machinery for moving electrons through this pathway. Recent studies show that the chiral-induced spin selectivity (CISS) effect is observable in some of these proteins extracted from the model metal-reducing bacteria, Shewanella oneidensis MR-1. It was hypothesized that the CISS effect facilitates efficient electron transport in these proteins by coupling electron velocity to spin, thus reducing the probability of backscattering. However, these studies focused exclusively on the cell surface electron conduits, and thus, CISS has not been investigated in upstream electron transfer components such as the membrane-associated MtrA, or periplasmic proteins such as small tetraheme cytochrome (STC). By using conductive probe atomic force microscopy measurements of protein monolayers adsorbed onto ferromagnetic substrates, we show that electron transport is spin selective in both MtrA and STC. Moreover, we have determined the spin polarization of MtrA to be ∼77% and STC to be ∼35%. This disparity in spin polarizations could indicate that spin selectivity is length dependent in heme proteins, given that MtrA is approximately two times longer than STC. Most significantly, our study indicates that spin-dependent interactions affect the entire extracellular electron transport pathway. [ABSTRACT FROM AUTHOR]

The lattice mismatch, defect, and weak interlayer coupling severely constrain the practical application of van der Waals heterojunctions (vdWHs) in the field of optoelectronic devices. Here, we introduced the 2D ferroelectric (FE) material AgBiP2Se6 to construct defect-free, low lattice-mismatched AgBiP2Se6/MoSe2 heterojunctions with different polariton directions (I, II, III). The AgBiP2Se6 layer can provide an excellent FE electric field to enhance the interlayer coupling and stiffness. The larger interlay stiffness reduces the probability of electron–phonon scattering and then results in significant carrier mobility (∼0.5 × 104 cm2 V−1 s−1) for configurations I and II. Phase transition of FE to paraelectric AgBiP2Se6 in the AgBiP2Se6/MoSe2 heterojunctions can be achieved under specific biaxial strain, which can effectively regulate the electronic structure. Applying the strain and electric field can regulate the bandgap and band alignment of configurations I and II. The photoelectric conversion efficiency of configuration I can reach as high as 20.54% under 2% biaxial strain. Furthermore, configuration II holds a nearly free electron state near the Fermi level under an electric field, which can act as a favorable electron transport channel. A design to strengthen interlayer coupling in the FE-based AgBiP2Se6/MoSe2 heterojunction has been proposed, and it can provide a new way to break through the traditional bottleneck in the development of optoelectronic devices. [ABSTRACT FROM AUTHOR]

We demonstrate a high electron conductivity (>102 S/cm and up to 103 S/cm) of tungsten suboxide W18O52.4−52.9 (or equivalently WO2.91−2.94) nanotubes (2–3 nm in diameter, ∼μm long). The conductivity is measured in the temperature range of 120–300 K by a four-probe scanning tunneling microscope in ultrahigh vacuum. The nanotubes are synthesized by a low-temperature and low-cost solvothermal method. They self-assemble in bundles of hundreds of nanotubes forming nanowires (∼μm long, few tens nm wide). We observe a large anisotropy of the conductivity with a ratio (longitudinal conductivity/perpendicular conductivity) of ∼105. A large fraction of them (∼65%–95%) shows a metallic-like, thermal activation-less electron transport behavior. Few of them, with a lower conductivity from 10 to 102 S/cm, display a variable range hopping behavior. In this latter case, a hopping barrier energy of ∼0.24 eV is inferred in agreement with the calculated energy level of the oxygen vacancy below the conduction band. This result is in agreement with a relative average concentration of oxygen vacancies of ∼3%, for which a semiconductor-to-metal transition was theoretically predicted. These tungsten suboxide nanostructures are prone to a wide range of applications in nanoelectronics. [ABSTRACT FROM AUTHOR]

Electron bifurcation (BF) is an evolutionarily ancient energy coupling mechanism in anaerobes, whose associated enzymatic machinery remains enigmatic. In BF-flavoenzymes, a chemically high-potential electron forms in a thermodynamically favorable fashion by simultaneously dropping the potential of a second electron before its donation to physiological acceptors. The cryo-EM and spectroscopic analyses of the BF-enzyme Fix/EtfABCX from Thermotoga maritima suggest that the BF-site contains a special flavin-adenine dinucleotide and, upon its reduction with NADH, a low-potential electron transfers to ferredoxin and a high-potential electron reduces menaquinone. The transfer of energy from high-energy intermediates must be carefully orchestrated conformationally to avoid equilibration. Herein, anaerobic size exclusion-coupled small-angle X-ray scattering (SEC-SAXS) shows that the Fix/EtfAB heterodimer subcomplex, which houses BF- and electron transfer (ET)-flavins, exists in a conformational equilibrium of compacted and extended states between flavin-binding domains, the abundance of which is impacted by reduction and NAD(H) binding. The conformations identify dynamics associated with the T. maritima enzyme and also recapitulate states identified in static structures of homologous BF-flavoenzymes. Reduction of Fix/EtfABCX's flavins alone is insufficient to elicit domain movements conducive to ET but requires a structural "trigger" induced by NAD(H) binding. Models show that Fix/EtfABCX's superdimer exists in a combination of states with respect to its BF-subcomplexes, suggesting a cooperative mechanism between supermonomers for optimizing catalysis. The correlation of conformational states with pathway steps suggests a structural means with which Fix/EtfABCX may progress through its catalytic cycle. Collectively, these observations provide a structural framework for tracing Fix/EtfABCX's catalysis.

Within the framework of an electron transport regime classification scheme, we aim to explore the boundaries that occur between the ballistic, collision-dominated, space-charge injection, and non-space-charge injection electron transport regimes that are experienced by an electron within a semiconducting device, mapping out where these different electron transport regimes are. We do this by determining the electron's mean free path and the relevant screening length. In order to make this analysis concrete, we perform this analysis for four representative semiconductor material systems, including silicon, gallium arsenide, the 4H-phase of silicon carbide, and the wurtzite phase of gallium nitride. The entire analysis is performed using a two-dimensional approach, this being representative of the electron transport that is experienced by an electron in the vicinity of a two-dimensional electron gas. Finally, following an evaluation of the dependence of the ballistic mobility on the device length scale for all four materials, an evaluation of the effective mobility as a function of the channel-length scale is pursued, a Matthiessen-rule based approach being employed for the purposes of this analysis. [ABSTRACT FROM AUTHOR]

The electron transport characteristics of magnetic and non-magnetic ferroelectric tunnel junctions based on Hf 0.5 Zr 0.5 O 2 are investigated in this study. A modified linear approach to the Thomas–Fermi interfacial screening model is employed to simulate these properties. This method is developed by leveraging the quantum approximation of the quasiclassical spin-resolved point-like contact formalism. The oxygen vacancies, voltage-induced screening, and electrostriction effect are the key phenomena exploited to build the potential profile and hence to simulate the resistive switching characteristics of the ferroelectric tunnel junctions. To validate its precision, the model is extensively verified with experimental data. The obtained model is generalized to reproduce mono-domain and multi-domain ferroelectric switching, featuring its effectiveness for non-volatile storage devices and ferroelectric-field effect transistors. [ABSTRACT FROM AUTHOR]

A memristor is a two-terminal electrical component with the scope of future computing applications and analog electronics. In this report, bismuth sulfide decorated one-dimensional carbon nitride nanotube was synthesized and characterized with various analytical techniques. The electrical property of the synthesized material was measured using a two-terminal metal–insulator–metal type of device that exhibited the resistive switching characteristics with the ON to OFF ratio of 2 × 103. The electron transport mechanism of the device was followed by Schottky emission and Poole–Frenkel emission for a low conductance state and Ohmic conduction behavior at the high conductance state. A decrease in the trap depth was identified in the simulation study with increasing applied potential and that supported the proposed mechanism. Read endurance and retention behavior of the device are stable in nature, supported by the statistical analysis. Furthermore, a hybrid logic gate was designed using two identical memristors, one CMOS inverter, one resistor, one voltage divider, and a buffer gate. The designed logic gate exhibited stable nand and nor gate operation based on the control signal. [ABSTRACT FROM AUTHOR]

The dynamics of (few) electrons dissolved in an ionic fluid—as when a small amount of metal is added to a solution while upholding its electronic insulation—manifests interesting properties that can be ascribed to nontrivial topological features of particle transport (e.g., Thouless' pumps). In the adiabatic regime, the charge distribution and the dynamics of these dissolved electrons are uniquely determined by the nuclear configuration. Yet, their localization into effective potential wells and their diffusivity are dictated by how the self-interaction is modeled. In this article, we investigate the role of self-interaction in the description of the localization and transport properties of dissolved electrons in non-stoichiometric molten salts. Although the account for the exact (Fock) exchange strongly localizes the dissolved electrons, decreasing their tunneling probability and diffusivity, we show that the dynamics of the ions and of the dissolved electrons are largely uncorrelated, irrespective of the degree to which the electron self-interaction is treated and in accordance with topological arguments. [ABSTRACT FROM AUTHOR]

Electron transport through a variety of helical structures has been shown to exhibit high-efficiency spin filtering, which is called chirality-induced spin selectivity (CISS). In this paper, we consider a helical chain of atomic p orbitals, which has been employed as a model in exploring the mechanism of CISS in previous theories, and show that the interatomic hopping along the helical chain induces an effective magnetic field (EMF) acting on the atomic orbital angular momentum (OAM). In chains where the curvature and torsion of the helix are small, we find that the EMF on the binormal component of the atomic OAM is created by the curvature, while that on the tangential component is produced by the torsion. We show that such coupling of the atomic OAM and the interatomic hopping leads to current-induced orbital and spin polarizations. We expect that the present coupling, which is expressed locally, can be used to estimate orbital and spin polarizations locally induced in molecules and solids. [ABSTRACT FROM AUTHOR]

A theoretical treatment of the multiple scattering problem for electrons in heavily doped semiconductors is developed for the purpose of resolving a long-standing discrepancy between theory and experiment on electron transport in semiconductors and semimetals. The scattering strength term in the traditional Brooks–Herring formula for ionized impurity scattering is modified to take into account the effect of the spatial proximity of ionized donors leading to an additional scattering term proportional to the cube of ionized impurity concentration, whereas the Brooks–Herring theory varies strictly linearly with the ionized impurity concentration. Comparisons between theory and experiment for GaAs, GaN, ZnO, and α-Sn are presented, showing significant improvement overall. In some cases, improvements greater than an order of magnitude are achieved. The agreement between theory and experiment for heavily doped ZnO over the temperature range of 21–322 K is within about 1%, depending on temperature. [ABSTRACT FROM AUTHOR]

The control of electron spin, crucial to the stability of matter, offers new possibilities for manipulating the properties of molecules and materials with potential applications in spintronics and chemical reactions. Recent experiments have demonstrated that electron transmission through chiral molecules depends on the electron spin orientation, a phenomenon known as chiral-induced spin selectivity (CISS). In this study, we show that CISS can be observed in achiral systems driven by an external circularly polarized laser field in the framework of Floquet engineering. By using the Floquet theory for a time-periodically driven system to investigate spin-dependent electron transport in a two-terminal setup, we demonstrate that the spin polarization can approach unity if the light intensity is sufficiently strong, the rate of dephasing is sufficiently low, and the average chemical potential of the two leads is within an appropriate range of values, which is narrow because of the high frequency of the laser field. To obtain a broader range of energies for large spin polarization, a combination of chiral molecules and light–matter interactions is considered, and the spin polarization of electrons transported through a helical molecule driven by a laser field is evaluated. [ABSTRACT FROM AUTHOR]

Reducing the gap between the electrodes to the nanoscale and utilizing quantum effects are an effective way to enhance the performance of a thermionic energy device. In this work, we establish the model of a photon-enhanced thermionic emission system with a nanoscale vacuum gap, where the electron transport due to electron tunneling and the near-field radiation resulting from photon tunneling are introduced. Analytical expressions for the thermionic emission current, electron tunneling current, and heat flux due to the near-field radiation are provided. By using the energy and particle balance equations, the electron concentration and the temperature of the cathode are determined. The impacts of the voltage, electron affinity, and gap distance on the performance are further analyzed. Results show that the suggested system can achieve high efficiency at the low-temperature cathode. Up to 34.7% of solar-to-electricity efficiency is possible at a cathode temperature of 472.5 K. The proposed model provides a strategy for designing highly efficient thermionic emission devices operating at low temperatures. [ABSTRACT FROM AUTHOR]

Rotating plasma structures, or "spokes," in magnetized discharges characterized by perpendicular electric and magnetic fields have been seen in a growing number of studies and are believed to be the result of gradient-driven drift instabilities. Under certain conditions, we have shown [Ito and Cappelli, Appl. Phys. Lett. 94, 211501 (2009)] the spoke's rotation to be opposite to the E × B direction, i.e., retrograde in its expected direction. Recently [Marcovati et al., J. Appl. Phys. 127, 223301 (2020)], we have linked such counter-intuitive rotation to a local inversion of the electric field. Here, we give further experimental evidence for this inversion and attempt to provide an explanation for a relatively distinct transition seen between retrograde and positive (prograde) drift. In the experiments, a partially magnetized plasma forms inside a magnetron device of ≈ 10 mm radius operated with argon. Discharge current–voltage measurements are acquired for a range of argon fill pressure and inter-electrode spacing. We find two branches of operation—a low current branch of negative resistance, coinciding with the retrograde spoke rotation, and a higher current branch of positive resistance, coincident with prograde spoke rotation. We postulate that at low discharge currents, high magnetic field confinement leads to a large density gradient, causing more electron transport to the anode than that demanded by the external circuit. At higher currents, anomalous axial electron transport (across the magnetic field lines) becomes dominant, eliminating the conditions for field inversion. The current thresholds for the field inversion are found to be sensitive to the argon pressure and inter-electrode spacing. [ABSTRACT FROM AUTHOR]

Different from conventional ferromagnetic methods, producing a spin-polarized current through electrical ways in spintronic devices can greatly increase operating speed, reduce power consumption, and improve device integration. Inspired by recent experimental progress on the synthesis of a heptauthrene molecule, we investigate its spin-dependent transport contacted with Au electrodes through first-principles calculations. By applying a gate voltage, the transmission can be switched between completely spin-up and spin-down polarized states, achieving an electrically controlled dual-spin filter. Furthermore, a fine tuning on the spin polarization, between 100% and − 100%, can also be realized, where the transport with any ratio of spin-up to spin-down electron quantities can be realized beyond the traditional devices. The peculiar transmission spectra and their shift are found to play crucial roles, where transmission peaks distribute on both sides of the Fermi level with opposite spin components. Such a spin-polarization modulating effect is found to be robust to the molecule-electrode contacting site, indicating it is an intrinsic feature of such systems. Moreover, the dimension of the device is at the single-molecule level, suggesting great application potential. [ABSTRACT FROM AUTHOR]

All-solid-state electric double-layer (EDL) thin-film transistors (TFTs) consisting of solution-processed LaZrO gate insulators and sputtered InO channels with thicknesses of 10–200 nm were prepared, and their microstructures and electrical properties were investigated. In addition, mobility, carrier concentration, and their gate-voltage dependence in the InO layer were analyzed during a transistor operation to clarify the electron transport properties. It was confirmed that LaZrO was amorphous and that InO crystallized and had an In2O3 bixbyite structure. The transfer conductance increased with the InO thickness, and its normalized value was maximized (3.6 mS/V) at an InO thickness of 200 nm. The maximum capacitance of LaZrO was 31 μF/cm2, strongly suggesting the formation of an EDL. Solid EDL-TFTs operated stably without deterioration at gate voltages up to 5 V, which usually degrade liquid-electrolyte EDL transistors via electrolysis. Assuming the formation of a 1-nm-thick EDL, the concentration of carrier electrons induced during the transistor operation was estimated to be 1019–1021 cm−3. Moreover, the mobility increased with the InO thickness and reached a maximum value of 68 cm2/(V s) at an InO thickness of 120 nm. The conduction electrons were significantly affected by grain boundary scattering and surface scattering, in addition to scattering within the crystal grain. An increase in the InO thickness, which improved the crystallinity in the crystal grain, reduced the barrier height and the effect of grain boundary scattering. [ABSTRACT FROM AUTHOR]

Summary: The superior productivity of C4 plants is achieved via a metabolic C4 cycle which acts as a CO2 pump across mesophyll and bundle sheath (BS) cells and requires an additional input of energy in the form of ATP. The importance of chloroplast NADH dehydrogenase‐like complex (NDH) operating cyclic electron flow (CEF) around Photosystem I (PSI) for C4 photosynthesis has been shown in reverse genetics studies but the contribution of CEF and NDH to cell‐level electron fluxes remained unknown.We have created gene‐edited Setaria viridis with null ndhO alleles lacking functional NDH and developed methods for quantification of electron flow through NDH in BS and mesophyll cells.We show that CEF accounts for 84% of electrons reducing PSI in BS cells and most of those electrons are delivered through NDH while the contribution of the complex to electron transport in mesophyll cells is minimal. A decreased leaf CO2 assimilation rate and growth of plants lacking NDH cannot be rescued by supplying additional CO2.Our results indicate that NDH‐mediated CEF is the primary electron transport route in BS chloroplasts highlighting the essential role of NDH in generating ATP required for CO2 fixation by the C3 cycle in BS cells. [ABSTRACT FROM AUTHOR]

Summary: Plants rely on solar energy to synthesize ATP and NADPH for photosynthetic carbon fixation and all cellular need. Mitochondrial respiration is essential in plants, but this may be due to heterotrophic bottlenecks during plant development or because it is also necessary in photosynthetically active cells.In this study, we examined in vivo changes of cytosolic ATP concentration in response to light, employing a biosensing strategy in the moss Physcomitrium patens and revealing increased cytosolic ATP concentration caused by photosynthetic activity.Plants depleted of respiratory Complex I showed decreased cytosolic ATP accumulation, highlighting a critical role of mitochondrial respiration in light‐dependent ATP supply of the cytosol. Consistently, targeting mitochondrial ATP production directly, through the construction of mutants deficient in mitochondrial ATPase (complex V), led to drastic growth reduction, despite only minor alterations in photosynthetic electron transport activity.Since P. patens is photoautotrophic throughout its development, we conclude that heterotrophic bottlenecks cannot account for the indispensable role of mitochondrial respiration in plants. Instead, our results support that mitochondrial respiration is essential for ATP provision to the cytosol in photosynthesizing cells. Mitochondrial respiration provides metabolic integration, ensuring supply of cytosolic ATP essential for supporting plant growth and development. [ABSTRACT FROM AUTHOR]

The AlCl 3 /ZnCl 2 aqueous solution acts as a benign cellulose solvent, polymerization catalyst for acrylamide monomer, effective ion source for electron transport networks, and dynamic riveting point for hydrogel networks. [Display omitted] The green synthesis strategy for cellulose-containing hydrogel electrolytes is significant for effectively managing resources, energy, and environmental concerns in the contemporary world. Herein, we propose an all-green strategy using AlCl 3 /ZnCl 2 /H 2 O solvent to create cellulose/polyacrylamide-based hydrogel (AZ-Cel/PAM) with expanded hierarchical topologies. The aqueous AlCl 3 /ZnCl 2 facilitates the efficient dissolution of cellulose at room temperature, and the dispersed Al3+-Zn2+ ions autocatalytic system catalyzes in-situ polymerization of acrylamide (AM) monomer. This expands the AM network within the cellulose framework, forming multiple bonding interactions and stable ion channels. The resulting hybrid hydrogel exhibits improved mechanical properties (tensile strength of 56.54 kPa and compressive strength of 359.43 kPa) and enhanced ionic conductivity (1.99 S/m). Furthermore, it also demonstrates excellent adhesion, freeze resistance (−45 °C), and water retention capabilities. Quantum simulations further clarify the mechanical composition and ion transport mechanism of AZ-Cel/PAM hydrogels. The assembled supercapacitor with the hydrogel electrolyte, demonstrates an ideal area-specific capacitance of 203.80 mF/cm2. This all-green strategy presents a novel approach to developing sustainable energy storage devices. [ABSTRACT FROM AUTHOR]

Manganese dioxide is attractive for energy storage but still needs to be combined with highly conductive materials to improve its electrochemical properties. In this paper, δ-MnO2/GNS composites with three-dimensional structures were synthesized by anchoring hydrangea-like δ-MnO2 on graphene substrates. Physicochemical analysis shows that δ-MnO2 is uniformly anchored on the graphene surface, and adjacent hydrangea-like δ-MnO2 self-assembles to build a three-dimensional conductive network, and this special structure not only provides abundant surface active sites but also more fast channels for electron transport during electrochemical reactions. The optimized composite (δ-MnO2/GNS-1.8) exhibited excellent electrochemical performance with a high specific capacitance of 326.6 F g−1 at a current density of 0.2 A g−1 and a cycling performance of 97.1%. Asymmetric supercapacitors assembled with δ-MnO2/GNS and activated carbon (AC) exhibited energy densities up to 42.2 W h kg−1 at a power density of 196.8 W kg−1. Hydrangea-like δ-MnO2 anchored on GNS has great potential for application as a high-performance supercapacitor electrode material. [ABSTRACT FROM AUTHOR]

A hydrophobic evaporable indano[60] fullerene ketone with low sublimation temperature (CF3-FIDO) was successfully synthesized, providing the fullerene mono-adduct derivative with the lowest sublimation temperature reported to date. The amorphous characteristic of the evaporated film was confirmed by grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). Perovskite solar cells using CF3-FIDO as the electron transport layer (ETL) achieved long-term device stability retaining 60% of their initial PCE after 500 h in air. [ABSTRACT FROM AUTHOR]

Achieving both high efficiency and stability in organic solar cells (OSCs) remains a significant challenge. Inverted structure OSCs, compared to those with a normal structure, show great potential for combining high efficiency with enhanced stability. However, despite their improved stability, the efficiencies of inverted OSCs still lag behind those of conventional structure OSCs, largely due to the performance of electron transport layers (ETLs). Herein, a water‐soluble hybrid ETL is developed by modifying SnO2 nanoparticles with an aqueous potassium carboxylate salt, PMA. This modification effectively passivates the oxygen vacancy defects in the SnO2 nanoparticles and eliminates the light soaking issue observed in the control device. As a result, the PM6:Y6‐based device shows an improvement in efficiency from 16.68% to 17.85% with PMA modification. Notably, an exceptional efficiency of 19.07% is achieved for the PM6:BTP‐eC9‐based device using this hybrid ETL, marking the highest efficiency reported to date for single‐junction inverted OSCs. In addition, all tested OSCs with the hybrid ETL demonstrate superior stability under both thermal and light illumination at the maximum power point compared to the control devices. Furthermore, utilizing this water‐processed hybrid ETL, a large‐area module based on PM6:BO‐4Cl is fabricated and shows an outstanding efficiency of 15.02%. [ABSTRACT FROM AUTHOR]

A computational methodology, founded on chemical concepts, is presented for interpreting the role of nuclear motion in the electron transport through single‐molecule junctions (SMJ) using many‐electron ab initio quantum chemical calculations. Within this approach the many‐electron states of the system, computed at the SOS‐ADC(2) level, are followed along the individual normal modes of the encapsulated molecules. The inspection of the changes in the partial charge distribution of the many‐electron states allows the quantification of the electron transport and the estimation of transmission probabilities. This analysis improves the understanding of the relationship between internal motions and electron transport. Two SMJ model systems are studied for validation purposes, constructed from a conductor (BDA, benzene‐1,4‐diamine) and an insulator molecule (DABCO, 1,4‐diazabicyclo[2.2.2]octane). The trends of the resulting transmission probabilities are in agreement with the experimental observations, demonstrating the capability of the approach to distinguish between conductor and insulator type systems, thereby offering a straightforward and cost‐effective tool for such classifications via quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is the most aggressive type of cancer in the brain and has an inferior prognosis because of the lack of suitable medicine, largely due to its tremendous invasion. GBM has selfish metabolic pathways to promote migration, invasion, and proliferation compared to normal cells. Among various metabolic pathways, NAD (nicotinamide adenine dinucleotide) is essential in generating ATP and is used as a resource for cancer cells. LbNOX (Lactobacillus brevis NADH oxidase) is an enzyme that can directly manipulate the NAD+/NADH ratio. In this study, we found that an increased NAD+/NADH ratio by LbNOX or mitoLbNOX reduced intracellular glutamate and calcium responses and reduced invasion capacity in GBM. However, the invasion was not affected in GBM by rotenone, an ETC (Electron Transport Chain) complex I inhibitor, or nicotinamide riboside, a NAD+ precursor, suggesting that the crucial factor is the NAD+/NADH ratio rather than the absolute quantity of ATP or NAD+ for the invasion of GBM. To develop a more accurate and effective GBM treatment, our findings highlight the importance of developing a new medicine that targets the regulation of the NAD+/NADH ratio, given the current lack of effective treatment options for this brain cancer. [ABSTRACT FROM AUTHOR]

Clothianidin (CL) is a neonicotinoid insecticide widely used in crop protection against insect pests. However, its effects on photosynthesis remain largely unknown. Here, by investigating the influence of CL at the concentrations of 22 and 110 μg/L on the primary processes of photosynthesis, membrane fluidity and structural changes of pea chloroplasts, we located several primary binding sites of this pesticide. Similar dynamics were observed for both concentrations. However, statistically significant differences were only found at 110 μg/L for all methods used. The light saturated rate of linear electron flow decreased mainly due to the disturbance of electron flow on the acceptor side of photosystem II (PSII) associated with the appearance of QB‐nonreducing centers and empty QB binding sites of PSII. The functioning of the donor side of PSII, the activity of photosystem I (PSI) and the maximum quantum yield of PSII photochemistry (Fv/Fm) were not found to be significantly altered. Increased membrane fluidity and structural alterations of the thylakoid membrane led to a decrease in the development of the proton gradient ΔрН and membrane energization processes. [ABSTRACT FROM AUTHOR]

Garnet solid‐state electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) holds significant promise. However, the practical utilization has been seriously impeded by the poor contact of Li|garnet and electron leakage. Herein, one new type of garnet‐based solid‐state battery is proposed with high performance through the disparity in interfacial energy, induced by the reaction between trace fluorinated carbon dots (FCDs) and Li. The work of adhesion of Li|garnet is increased by the acquired Li‐FCD composite, which facilitates an intimate Li|garnet interface with the promoted uniform Li+ deposition, revealed by density functional theory (DFT) calculations. It is further validated that a concentrated C−Li2O−LiF component at the Li|garnet interface is spontaneously constructed, due to the significant disparity in interfacial energy between C−Li2O−LiF|LLZTO and C−Li2O−LiF|Li. Furthermore, The electron transport and Li dendrites penetration are effectively hindered by the formed Li2O and LiF. The Li‐FCD|LLZTO|Li‐FCD symmetrical cells demonstrate stable cycling performance for over 3000 hours at 0.3 mA cm−2 and 800 hours at 0.5 mA cm−2. Furthermore, the LFP|garnet|Li‐FCD full cell exhibits remarkable cycling performance (91.6 % capacity retention after 500 cycles at 1 C). Our research has revealed a novel approach to establish a dendrite‐free Li|garnet interface, laying the groundwork for future advancements in garnet‐based solid‐state batteries. [ABSTRACT FROM AUTHOR]

Bamboo fiber has attracted attention due to its high strength and flexibility, but it shows poor electron mobility and functionalities. In this research, phosphorus-doped flexible electrodes were constructed using bamboo fiber as the substrate, which was pretreated using sodium borohydride, followed by chemical nickel plating, and then used for urea electrocatalytic oxidation. The results showed that the bamboo fiber film provided a flexible support for nickel metal loading and a uniform and dense metal coating. Along with phosphorus self-doping, this conferred significant electrocatalytic activity to the nickel-phosphorus/bamboo fiber film (Ni–P/BFF). Notably, the electrode demonstrated an initial oxidation potential of 436.4 mV during urea oxidation. Phosphorus doping induced charge density redistribution and changed the electronic states during chemical plating, making the area around nickel atoms effective electron-trapping centers. This lowered the free energy of OH− adsorption on the surface of the conductive network in the electrolyte, which in turn lowered the onset potential and Tafel slope. These findings present a novel perspective for using biomass materials to create flexible electrodes. [Display omitted] • Eco-friendly, high-performance and low-cost flexible electrode material based on natural bamboo fiber was created. • The conductive network on bamboo fibers constitutes electron transport channels and provide electrocatalytic active sites. • Self-doping with phosphorus significantly enhanced the electrocatalytic activity, particularly for urea oxidation. [ABSTRACT FROM AUTHOR]

To investigate the effects of ocean acidification (OA) and nitrogen limitation on macroalgae growth and photophysiological responses, Gracilariopsis lemaneiformis was cultured under two main conditions: ambient (Low CO2, LC, 390 matm) and CO2 enriched (High CO2, HC, 1000 matm), with low (LN, 7 mmol L-1) and high (HN, 56 mmol L-1) nitrate. High CO2 levels decreased growth under both LN and HN treatments. HC reduced Chl a, carotenoids, phycoerythrin (PE), and phycocyanin (PC) under HN conditions, while only Chl a decreased under LN conditions. NO3 - uptake rate was restricted under LN compared to HN, while HC enhanced it under HN. Net photosynthetic O2 evolution rates did not differ between CO2 and nitrate treatments. Dark respiration rates were higher under HN, further boosted by HC. The stimulated effective quantum yield (Y(II)) corresponded to decreased non-photochemical quenching (NPQ) under HN conditions. Nitrate, not CO2, showed significant effects on the relative electron transport rate (rETRmax), light use efficiency (a) and saturation light intensity (Ik) that with lowered rETRmax and a under LN culture. Our results indicate that OA may negatively affect Gracilariopsis lemaneiformis growth and alter its photophysiological performance under different nutrient conditions. [ABSTRACT FROM AUTHOR]

MXene is a rapidly emerging group of two-dimensional (2D) multifunctional nanomaterials, drawing huge attention from researchers of a broad scientific field. Reporting the synthesis of MXene was the following breakthrough in 2D materials following the discovery of graphene. MXene is considered the most recent developments of materials, including transition metal carbonitrides, nitrides, and carbides synthesized by etching or mechanical-based exfoliation of selective MAX phases. MXene has a plethora of prodigious properties such as unique interlayer spacing, high ion and electron transport, large surface area, excellent thermal and electrical conductivity, exceptional volumetric capacitance, thermal shock, and oxidation resistance, easily machinable and inherently hydrophilic, and biocompatibility. Owing to the abundance of tailorable surface function groups, these properties can be further enhanced by surface functionalization with covalent and non-covalent modifications via numerous surface functionalization methods. Therefore, MXene finds their way to a plethora of applications in numerous fields including catalysis, membrane separation, energy storage, sensing, and biomedicine. Here, the focus is on reviewing the structure, synthesis techniques, and functionalization methods of MXene. Furthermore, MXene-based detection platforms in different sensing applications are survived. Great attention is given to reviewing the applications of MXene in the detection of biomolecules, pathogenic bacteria and viruses, cancer biomarkers food contaminants and mycotoxins, and hazardous pollutants. Lastly, the future perspective of MXene-based biosensors as a next-generation diagnostics tool is discussed. Crucial visions are introduced for materials science and sensing communities to better route while investigating the potential of MXene for creating innovative detection mechanisms. [ABSTRACT FROM AUTHOR]

Water pollution has always been an inescapable challenge in the development of human society. Photocatalytic technology is regarded as a promising strategy for water pollution control. In this work, a novel Cu2O/TiO2@Ti3C2Tx MXene photocatalyst is constructed to create diverse electron transport pathways, thereby promoting charge separation and achieving superior photocatalytic performance. The synergistic effects of composite photocatalytic materials are instrumental in degrading organic dyes under visible light. The successful construction of a heterojunction structure between Cu2O and in situ generated TiO2 mitigates charge recombination post-separation, significantly extending the lifetime of photogenerated carriers. Additionally, the incorporation of Ti3C2Tx serves as an effective conductive medium, facilitating the separation and transfer of photogenerated charges within the material. Therefore, the Cu2O/TiO2@Ti3C2Tx MXene composites exhibit exceptional photocatalytic activity, showcasing the best performance, achieving a degradation rate of 71.5% after 3 h of visible light irradiation. These findings underscore the potential of this new compound in enhancing photocatalytic organic degradation, highlighting the promising application prospects of photocatalytic materials. [ABSTRACT FROM AUTHOR]

This article delves into the domain of low bandgap perovskite solar cells, driven by the quest for enhanced device performance and expanded access to various solar energy spectra. The study systematically explores the materials, device design, and optimization strategies pertinent to low bandgap perovskite solar cells. The initial section focuses on the current status of low bandgap perovskite materials, scrutinizing approaches to enhance bandgap, stability, and charge transport. Novel materials such as mixed-halide perovskites, double perovskites, and perovskite quantum dots are examined to improve efficiency and broaden the spectral utilization. The investigation culminates in a comprehensive exploration of diverse device topologies aimed at enhancing the performance of low bandgap perovskite solar cells. This encompasses discussions on electron and hole transport materials, interfacial engineering techniques, various device designs, tandem configurations, and their respective merits and limitations. Additionally, the research scrutinizes methodologies to enhance the performance of low-bandgap perovskite solar cells, with a specific focus on light management, charge extraction, and mitigating recombination losses. The incorporation of passivation layers and interfacial modifications is discussed as a strategy for bolstering device stability and mitigating deterioration through interface engineering. [ABSTRACT FROM AUTHOR]

Summary: Human skeletal muscle mitochondria regulate energy expenditure. Research has shown that the functionality of muscle mitochondria is altered in subjects with overweight, as well as in response to nutrient excess and calorie restriction. Two metabolic features of obesity and overweight are (1) incomplete muscular fatty acid oxidation and (2) increased circulating lactate levels. In this study, I propose that these metabolic disturbances may originate from a common source within the muscle mitochondrial electron transport system. Specifically, a reorganization of the supramolecular structure of the electron transport chain could facilitate the maintenance of readily accessible coenzyme Q pools, which are essential for metabolizing lipid substrates. This approach is expected to maintain effective electron transfer, provided that there is sufficient complex III to support the Q‐cycle. Such an adaptation could enhance fatty acid oxidation and prevent mitochondrial overload, thereby reducing lactate production. These insights advance our understanding of the molecular mechanisms underpinning metabolic dysregulation in overweight states. This provides a basis for targeted interventions in the quest for metabolic health. [ABSTRACT FROM AUTHOR]

Photorespiration is an essential process related to photosynthesis that is initiated following the oxygenation reaction catalyzed by rubisco, the initial enzyme of the Calvin–Benson–Bassham cycle. This reaction produces an inhibitory intermediate that is recycled back into the Calvin–Benson–Bassham cycle by photorespiration which requires the use of energy and the release of a portion of the carbon as CO2. The energy use and CO2 release of canonical photorespiration form a foundation for biochemical models used to describe and predict leaf carbon exchange and energy use (ATP and NAPDH). The ATP and NADPH demand of canonical photorespiration is thought to be different than that of the Calvin–Benson–Bassham cycle, requiring increased flexibility in the ratio of ATP and NADPH from the light reactions. Photorespiration requires many reactions across the chloroplasts, mitochondria and peroxisomes and involves many intermediates. Growing evidence indicates that these intermediates do not all stay in photorespiration as typically assumed and instead feed into other aspects of metabolism and leave as glycine, serine, and methylene‐THF. Here we discuss how alternative flux through and from canonical photorespiration alters the ATP and NADPH requirements of metabolism following rubisco oxygenation using additional derivations of biochemical models of leaf photosynthesis and energetics. Using these new derivations, we determine that the ATP and NADPH demands of photorespiration are highly sensitive to alternative flux in ways that fundamentally changes how photorespiration contributes to the ratio of total ATP and NADPH demand. Specifically, alternative flows of carbon through photorespiration could reduce ATP and NADPH demand ratio to values below what is produced from linear electron transport. Summary statement: All carbon produced following rubisco‐catalyzed reaction with oxygen may not flow through textbook photorespiration. Here we review the consequences of this "noncanonical" carbon flow to the ATP and NADPH demands of this vital process. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are emerging as one of the most promising energy sources for space applications. However, the displacement damage of solar cells in the space environment has gradually deteriorated their performance. In this work, the depth distribution of primary knocked-on atoms (PKA), non-ionizing energy loss and defect concentration of CsPbI3-based perovskite solar cells irradiated by 0.1–2000 MeV protons have been simulated by the Geant4 toolkit. It is found that the PKA yield shows an obvious step behavior near the layer boundary of the solar cell, and that the electron and hole transport layers have the high defect concentration whereas the CsPbI3-based perovskite layer owns the least PKA yield. In particular, in the geostationary orbit, the radiation damage effect caused by space protons to the solar cells is approximately equivalent to that irradiated by 0.18 MeV protons, which provides a good reference for ground irradiation experiments for CsPbI3-based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Bi(III)‐based oxides are emerging as important semiconductors for future electronic applications. Through hybrid density functional theory calculations and defect analysis, we demonstrate that ABi(III)O2 (A = Na or K) is a promising wide‐band‐gap bipolar semiconductor. Our calculations predict ABiO2 to have a large band gap of 1.97 eV for NaBiO2 and 2.77 eV for KBiO2. Unlike widely‐used oxide semiconductors such as In2O3 and ZnO, the spatially extended cation states (Bi 6s) of ABiO2 significantly contribute to the valence band maximum, enhancing p‐type dopability. We indeed show that potential acceptors, such as SrBi, produce shallow levels. In addition, n‐type doping is found to be possible through the extrinsic doping of heterovalent elements such as Te and F. The band‐structure analysis reveals that ABiO2 has small effective masses for electrons and holes (< 1m0 where m0 is the electron rest mass), indicating favorable electron and hole transport properties. [ABSTRACT FROM AUTHOR]