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Fast ion beams induce damage to deoxyribonucleic acid (DNA) by chemical products, including secondary electrons, produced from interaction with liquid water in living cells. However, the production process of these chemical products in the Bragg peak region used in particle therapy is not fully understood. To investigate this process, we conducted experiments to evaluate the radiolytic yields produced when a liquid water jet in vacuum is irradiated with MeV-energy carbon beams. We used secondary ion mass spectrometry to measure the products, such as hydronium cations (H3O+) and hydroxyl anions (OH−), produced along with ·OH radicals, which are significant inducers of DNA damage formation. In addition, we simulated the ionization process in liquid water by incident ions and secondary electrons using a Monte Carlo code for radiation transport. Our results showed that secondary electrons, rather than incident ions, are the primary cause of ionization in water. We found that the production yield of H3O+ or OH− was linked to the frequency of ionization by secondary electrons in water, with these electrons having energies between 10.9 and 550 eV. These electrons are responsible for ionizing the outer-shell electrons of water molecules. Finally, we present that the elementary processes contribute to advancing radiation biophysics and biochemistry, which study the formation mechanism of DNA damage. [ABSTRACT FROM AUTHOR]

In this study, we explored the phase stability of quaternary Mo 1 − x M x AlB (M = Cr, Fe, Mn, Nb, Sc, Ta, Ti, V, and W) solid solutions by employing a cluster expansion method to generate structures with different concentrations of M atoms. Using the first-principles calculations based on density functional theory, we predicted that these compounds exhibit a preference for either fully random structures or phase-segregated (M-rich regions) phases against the competing phases. To evaluate the Gibbs free energy of Mo 1 − x M x AlB alloys, we investigated the impact of various entropy contributions, including configurational, electronic, and vibrational entropy. Our study revealed that configurational entropy plays an important role in stabilizing the random phases observed in Mo 1 − x M x AlB compounds, highlighting its importance in understanding the thermodynamic behavior of these alloys. However, the vibrational and electronic entropy changes with respect to competing phases can stabilize or destabilize Mo 1 − x M x AlB depending on their sign. Our results indicate that, while W is soluble across the entire range of mixing ratios, Sc and Ti are completely insoluble in any ratio. On the other hand, Cr, Ta, Nb, and V can be successfully incorporated into the MoAlB lattice at varying fractions at elevated temperatures. The size, valence electron concentration, and electronegativity differences between Mo and M can be utilized as descriptors to identify stable Mo 1 − x M x AlB compounds. We extensively examined the structural, dynamical stability, thermal conductivity, and mechanical properties of Mo 1 − x M x AlB compounds. We analyze their dependence on the choice of the M element incorporated in the alloy. Our findings can guide the design and engineering of these materials to tailor their properties to specific applications based on the choice of the M element. [ABSTRACT FROM AUTHOR]

The study of anisotropic magnetoresistance (AMR) holds dual significance in both theoretical and applied contexts. The underlying mechanisms of AMR remain unclear, and the phenomenon of AMR sign reversal (positive and negative transitions in values) has garnered multiple interpretations, demanding experimental verification. In this work, the effect of epitaxial strain on magnetic and transport properties of perovskite manganese oxide La0.35Sr0.65MnO3 films is investigated. The AMR demonstrates sign reversal and symmetry change behaviors. The symmetry changes of AMR stem from the competition between Zeeman energy, exchange interaction energy, and magnetocrystalline anisotropy energy. The sign reversal of AMR is attributed to the change in the density of states of spin up and spin down of conduction electrons during the magnetic phase transition induced by epitaxial strain. Our work offers experimental evidence and a reasonable explanation for the origin of the sign reversal of AMR. [ABSTRACT FROM AUTHOR]

In 3D-deposited AgNW/TiO2, which is prepared by spray-applying titanium dioxide suspension to deposited silver nanowire sheets, the synergistic effects of increased crossing points of AgNWs to enhance localized surface plasmon resonance excitation and longer-lived electrons in the conduction band of TiO2 generated by plasmon-induced charge transfer have successfully resulted in photocatalytic activity in the visible light range. We have developed photocatalytic sheets in which TiO2 particles are uniformly attached to 3D-deposited AgNWs. Regarding the prepared sheet, it was confirmed that TiO2 was indeed well adhered to the AgNWs, and electron transfer was efficient at the interface. This sheet solves the problem that the response wavelength range of the photocatalytic reaction using TiO2 is only in the ultraviolet region and exhibits sufficient photocatalytic effect in the visible light region. Transient absorption spectroscopy measurements in the diffuse reflectance configuration confirmed that the electrons of AgNWs actually move into the conduction band of TiO2 under visible light and that the interaction is independent of the excitation light intensity, thereby extending the lifetime of the electrons. [ABSTRACT FROM AUTHOR]

High-accuracy molecular force field models suited for hot gases and plasmas are not as abundant as those geared toward ambient pressure and temperature conditions. Here, we present an improved version of our previous electron-density based force field model that can now account for polarization effects by adjusting the atomic valence electron contributions to match ab initio calculated Mulliken partial charges. Using a slightly modified version of the Hohenberg–Kohn theorem, we also include an improved theoretical formulation of our model when applied to systems with degenerate ground states. We present two variants of our polarizable model, fitted from ab initio reference data calculated at CCSD(T)/cc-pVTZ and CCSD(T)/CEP-31G levels of theory, that both accurately model water dimer interaction energies. Further improvements include the additional interaction components with fictitious non-spherically symmetric, yet atom-centered, electron densities and fitting the exchange and correlation coefficients against analytical expressions. The latter removes all unphysical oscillations that are observed in the previous non-polarizable variant of our force field. [ABSTRACT FROM AUTHOR]

CNDOL is an a priori, approximate Fockian for molecular wave functions. In this study, we employ several modes of singly excited configuration interaction (CIS) to model molecular excitation properties by using four combinations of the one electron operator terms. Those options are compared to the experimental and theoretical data for a carefully selected set of molecules. The resulting excitons are represented by CIS wave functions that encompass all valence electrons in the system for each excited state energy. The Coulomb–exchange term associated to the calculated excitation energies is rationalized to evaluate theoretical exciton binding energies. This property is shown to be useful for discriminating the charge donation ability of molecular and supermolecular systems. Multielectronic 3D maps of exciton formal charges are showcased, demonstrating the applicability of these approximate wave functions for modeling properties of large molecules and clusters at nanoscales. This modeling proves useful in designing molecular photovoltaic devices. Our methodology holds potential applications in systematic evaluations of such systems and the development of fundamental artificial intelligence databases for predicting related properties. [ABSTRACT FROM AUTHOR]

Five high entropy carbide ceramics, (Hf0.2,Nb0.2,Ta0.2,Ti0.2,Zr0.2)C, (Cr0.2,Hf0.2,Ta0.2,Ti0.2,Zr0.2)C, (Hf0.2,Mo0.2,Ta0.2,Ti0.2,Zr0.2)C, (Hf0.2,Ta0.2,Ti0.2,W0.2,Zr0.2)C, and (Hf0.2,Mo0.2,Ti0.2,W0.2,Zr0.2)C, were synthesized by carbothermal reduction of oxides and direct current sintering. The five high entropy carbide ceramics were determined to be nominally phase-pure with relative densities of more than 98.9% and mean grain sizes of less than 5 μm. Average Vickers hardness values ranged from 19.2 ± 0.4 GPa for (Hf0.2,Nb0.2,Ta0.2,Ti0.2,Zr0.2)C at a load of 2 kgf to 43.5 ± 0.4 GPa for (Hf0.2,Mo0.2,Ti0.2,W0.2,Zr0.2)C at a load of 0.05 kgf. Hardness generally increased with increasing the valence electron concentration and strain as measured by the Williamson–Hall analysis. However, neither correlation was conclusive enough to be a clear indicator of hardness. Instead, it was determined that a combination of effects that includes the valence electron concentration, lattice strain, and grain size all contribute to the hardness of high entropy carbide ceramics. [ABSTRACT FROM AUTHOR]

The orthorhombic phase of FeNbO4, a promising anode material for solid oxide fuel cells (SOFCs), exhibits good catalytic activity toward hydrogen oxidation. However, the low electronic conductivity of the material specifically in the pure structure without defects or dopants limits its practical applications as an SOFC anode. In this study, we have employed density functional theory (DFT + U) calculations to explore the bulk and electronic properties of two types of doped structures, Fe0.9375A0.0625NbO4 and FeNb0.9375B0.0625O4 (A, B = Ti, V, Cr, Mn, Co, Ni) and the oxygen-deficient structures Fe0.9375A0.0625NbO3.9375 and FeNb0.9375B0.0625O3.9375, where the dopant is positioned in the first nearest neighbor site to the oxygen vacancy. Our DFT simulations have revealed that doping in the Fe sites is energetically favorable compared to doping in the Nb site, resulting in significant volume expansion. The doping process generally requires less energy when the O-vacancy is surrounded by one Fe and two Nb ions. The simulated projected density of states of the oxygen-deficient structures indicates that doping in the Fe site, particularly with Ti and V, considerably narrows the bandgap to ∼0.5 eV, whereas doping with Co at the Nb sites generates acceptor levels close to 0 eV. Both doping schemes, therefore, enhance electron conduction during SOFC operation. [ABSTRACT FROM AUTHOR]

A significant development toward semiconductor-based electronic devices is based on the electric and magneto-electric control of the transport properties of the charge carriers. This study unprecedentedly investigates the Ti implantation and thereafter the effect of structural defects on the electrical and magneto-electric transport properties of Ti-implanted RF-sputtered ZnO thin films. Theoretical stopping and range of ions in matter simulations along with the experimental structural and elemental studies reveal that Ti ion implantation generates a significant amount of oxygen vacancy (VO) defects apart from Ti-related impurities in post-implantation annealed films. The film implanted with 8 × 1015 ions/cm2 (TZO815) exhibits the lowest resistivity (4.68 × 10−3 Ω cm) and the highest carrier concentration (6.61 × 1020 cm−3) values. Resistivity measurements over a temperature range of 5-300K indicate semiconducting behavior for all the films implanted up to fluences of 5 × 1015 ions/cm2 identified with a grain boundary dominated thermally activated band, nearest neighbor hopping, and Mott and Efros–Shklovskii (ES) variable range hopping conduction mechanisms at various temperature intervals. Notably, the gradual decrease in both Mott and ES hopping ranges following Ti implantation indicates the formation of more localized states. Interestingly, the TZO815 film exhibits metal-semiconductor transition around 220 K, suggesting the formation of a degenerate band within the ZnO conduction band upon Ti implantation. Remarkably, the magnetoresistance results align with a semiempirical formula proposed by Khosla and Fischer, indicating that a negative magneto resistance in the TZO thin films is attributed to the spin-dependent scattering of conduction electrons by the localized magnetic moments induced mainly by the implantation induced VO defects. [ABSTRACT FROM AUTHOR]

The rates and pathways of chemical reactions at metal surfaces can be strongly influenced by energy dissipation due to the nonadiabatic excitation of metallic conduction electrons. The introduction of frictional forces to account for this dissipation has been quite successful in situations for which the nonadiabatic coupling is weak. However, in cases where nonadiabatic coupling is strong, such as when electron transfer occurs, the friction model is likely to break down. Ryabinkin and Izmaylov have proposed 2-state and 3-state alternatives to the friction model for introducing electronic dissipation in molecular dynamics simulations. Here, we examine their 2-state model using some simple examples of atom–surface scattering. We find that, with the addition of decoherence, the 2-state model can produce quite promising results. [ABSTRACT FROM AUTHOR]

The characteristic x-ray emission direction of a material indicates the direction of the bonding orbitals and spatial symmetry of the electron orbitals. Accordingly, the intensity of x-ray emission, which varies with the direction of emission and crystal orientation, provides crucial information regarding anisotropic electronic structures. This study utilized angle-resolved soft x-ray emission spectroscopy (SXES) on a layered material, NaAlSi, to ascertain the spatial distribution of the valence electrons. Distinct alterations in the spectral intensity distributions were observed in the Al–L2,3 and Si–L2,3 spectra with respect to the emission angle. To interpret the anisotropic SXES spectra, the spatial distribution of each valence electronic state was simulated using first-principle calculations. Although the anisotropic emission intensity could not explain the symmetry of the spatial distributions of the isolated s and d atomic orbitals, the anisotropy of the SXES spectra could be interpreted as the spatial distribution of these orbitals when hybridized with p orbitals. Furthermore, the spectral structure corresponding to the electronic states near the Fermi level reflected the characteristics of the d orbitals. Therefore, angle-resolved SXES measurements can effectively discern the spatial distribution of hybridized electron orbitals with specific energy levels, which could enhance techniques related to electron distribution analysis, with potential applications in material science and electronic structure characterization. [ABSTRACT FROM AUTHOR]

The characteristic polytype behaviors of SiC and accompanying low stacking fault energies are known to cause engineering issues, including polytype inclusions and bipolar degradation. The dependence of the relative stability of SiC polytypes and stacking fault energies on excess carrier concentration was investigated using first-principles calculations. The relative energy of 2H-, 4H-, and 6H-SiC to 3C-SiC increased with the excess electrons over 2 × 1019 cm−3, while the energy variation with excess holes was small. The stacking fault energies in 4H-SiC also exhibited a significant decrease with excess electrons over 1.0 × 1019 cm−3, whereas this change was minor with excess holes. These excess carrier dependencies were attributed to variations in the bandgap between polytypes. The energy level of the excess electrons was at the conduction band minimum; this was lowest in 3C-SiC, which had the lowest bandgap energy. Consequently, the energy of 3C-SiC with excess electrons was lower than that of other polytypes. Conversely, the valence band maximum lacked electrons when excess holes were present, resulting in a small difference among the Fermi levels of the polytypes. Hence, the energy difference between the SiC polytypes was similar for excess holes. Similarly, the stacking faults in SiC exhibited quantum-well structures by incorporating other polytypes with different bandgaps. With excess electrons, the Fermi level within the stacking faults was lower than that in the bulk crystals. Consequently, the stacking fault energy decreased for the same reason that the energy in 3C-SiC decreased under excess electron conditions. [ABSTRACT FROM AUTHOR]

4H silicon carbide (SiC) polytype is preferred over other SiC polytypes for high-power, high-voltage, and high-frequency applications due to its superior electrical, thermal, and structural characteristics. In this manuscript, we provide a comprehensive study of the spin coupling dynamics between conduction electrons and nitrogen (N) donors in monocrystalline 4H SiC with various concentrations of uncompensated N donors from 1017 to 5 × 1019 cm−3 by continuous wave, pulsed electron paramagnetic resonance (EPR), and microwave perturbation techniques at T = 4.2–300 K. At low temperatures, two triplets due to N donors in cubic (Nk) hexagonal (Nh) positions and triplet arisen from spin-interaction between Nh and Nk were observed in 4H SiC having Nd − Na ≈ 1017 cm−3. A single S-line (S = 1/2) dominates the EPR spectra in all investigated 4H SiC monocrystals at high temperatures. It was established that this line occurs due to the exchange coupling of localized electrons (dominate at low temperatures) and non-localized electrons (dominate at high temperatures). The localized electrons were attributed to Nh for Nd − Na ≈ 1017 cm−3 and Nk donors for Nd − Na ≥ 5 × 1018 cm−3. We have concluded that the conduction electrons in 4H SiC monocrystals are characterized by g|| = 2.0053(3) and g⊥ = 2.0011(3) for Nd − Na ≤ 5 × 1018 cm−3 and g|| = 2.0057(3) and g⊥ = 2.0019(3) for Nd – Na ≈ 5 × 1019 cm−3. Using the theoretical fitting of the temperature variation of S-line EPR linewidth in 4H SiC having Nd – Na ≤ 5 × 1018 cm−3, the energy levels of 57–65 meV that correlate with the valley-orbit splitting values for Nk donors in 4H SiC monocrystals were obtained. [ABSTRACT FROM AUTHOR]

We report a study on the electronic structure and chemical bonding of the BiB molecule using high-resolution photoelectron imaging of cryogenically cooled BiB− anion. By eliminating all the vibrational hot bands, we can resolve the complicated detachment transitions due to the open-shell nature of BiB and the strong spin–orbit coupling. The electron affinity of BiB is measured to be 2.010(1) eV. The ground state of BiB− is determined to be 2Π(3/2) with a σ2π3 valence electron configuration, while the ground state of BiB is found to be 3Σ−(0+) with a σ2π2 electron configuration. Eight low-lying spin–orbit excited states [3Σ−(1), 1Δ(2), 1Σ+(0+), 3Π(2), 3Π(1), 1Π(1)], including two forbidden transitions, [3Π(0−) and 3Π(0+)], are observed for BiB as a result of electron detachment from the σ and π orbitals of BiB−. The angular distribution information from the photoelectron imaging is found to be critical to distinguish detachment transitions from the σ or π orbital for the spectral assignment. This study provides a wealth of information about the low-lying electronic states and spin–orbit coupling of BiB, demonstrating the importance of cryogenic cooling for obtaining well-resolved photoelectron spectra for size-selected clusters produced from a laser vaporization cluster source. [ABSTRACT FROM AUTHOR]

The prime goal of this novel work is to investigate the efficacy of spinel zinc ferrite as a thermoelectric material and its performance enhancement for high temperature applications. Zn 1-x Ni x Fe 2 O 4 (0 ≤ x ≤ 0.2) were prepared by sol-gel method and their structural, morphological, and thermoelectric behaviours were examined as functions of composition and temperature. Among the studied compositions, Zn 0.8 Ni 0.2 Fe 2 O 4 exhibits the highest electrical conductivity (σ) of 49.83 S/m, the largest power factor of 6.66 μW/mK2, and the lowest thermal conductivity (κ) of 0.36 W/mK at 947 K, thus extending to an overall enhancement in the thermoelectric figure of merit (zT). Conduction through electron hopping is proven to be the main driving force for the enhancement in electrical and thus thermoelectric properties. Results reveal that thermoelectric properties of ZnFe 2 O 4 can potentially be enhanced by the doping Ni at Zn site and opens up an exciting opportunity for the utilization of this spinel ferrite as a novel thermoelectric material for applications involving elevated temperatures. [Display omitted] • Thermoelectric figure of merit of ZnFe 2 O 4 was considerably enhanced by doping Ni. • Electron hopping is found to be one of the major contributors for the enhancement of electrical conductivity. • The dopant is also effective in reducing the thermal conductivity of ZnFe 2 O 4 at higher temperatures. • The results indicate that the studied material is suitable for high temperature (>700K) thermoelectric applications. [ABSTRACT FROM AUTHOR]

This present work concerns the effect of ternary addition of non‐metallic and diamagnetic silicon on the metastable solubility of the immiscible silver‐cobalt system during the course of ball milling, annealing of the ball milled samples and the corresponding magnetic properties. It should be noted that silicon has a smaller goldsmidt radius (111 pm) than silver (144 pm) and silicon+4 has more valence electrons than silver+1. Keeping the objectives of the current study in mind, silicon may thus be considered as an option for ternary addition, in contrast to metallic components. An attempt has been made to examine the phase changes that occurred in the 50 silver‐40 cobalt‐10 silicon (atom percent) system during ball milling and the subsequent isothermal annealing of the ball milled product. Phase evolution during mechanical alloying and isothermal annealing is identified by means of x‐ray diffraction, differential thermal analysis, high resolution transmission electron microscopy and magnetic measurements. The addition of silicon facilitates cobalt‘s formation of a metastable alloy with copper after 50 hours of ball milling. Annealing significantly improves the magnetic characteristics of materials that have been ball milled; the optimal combination of magnetic properties was obtained after an hour of annealing at 550 °C. [ABSTRACT FROM AUTHOR]

The study presents the ideal distribution of graphene nanoplatelets (GNP) within the thermoplastic starch (TPS) matrix significantly elevated the thermal and electrical conductivities, as well as the electrochemical efficiency of the biocomposites. Additionally, the incorporation of GNP resulted in an increased thermal stability for the TPS, as indicated by the elevated temperatures required for maximum degradation. The biocomposites exhibited a self‐aligned layered structure, creating conductive pathways and enhancing electron conduction. An electrical conductivity increased as the concentration of GNP increased, with the highest conductivity observed on the top and bottom surface with the value of 4.23 × 10−7 S/m and 3.92 × 10−6 S/m when 12 wt% of GNP was added. The presence of hydroxyl groups in TPS facilitated the formation of hydrogen bonds with GNP, preventing GNP from stacking and forming a more uniform conductive network within the film. The addition of 15 wt% GNP also improved the capacitive performance of the TPS matrix, as evidenced by higher current responses and larger quasi‐rectangular areas in the cyclic voltammetry curves compared to neat TPS. The Nyquist plots which are illustrated impedance data showed that the TPS film with 12 wt% GNP exhibits the smallest semicircle, indicating the highest conductivity which is suggested that GNP improves charge transfer compared to pure TPS. Highlights: Optimal dispersion of GNP enhanced the biocomposite's properties.The electrical conductivity increases with the GNP content until 12 wt%.TPS/GNP self‐aligned layered improved conduction and capacitive behavior.GNP improved thermal stability by restricting polymer chain movement.Electrochemical impedance shows improved properties of TPS/GNP. [ABSTRACT FROM AUTHOR]

Zn–air batteries (ZABs) are promising next‐generation energy storage devices due to their low cost, intrinsic safety, and environmental benignity. However, the sluggish kinetics of the cathodic reactions severely limits the ZAB performances in practical use, calling for high‐efficiency bifunctional oxygen reduction and evolution electrocatalysts. Herein, an ultrahigh‐active bifunctional electrocatalyst is developed with a record‐low ΔE of 0.56 V, significantly outperforming the noble‐metal‐based benchmark (Pt/C+Ir/C, ΔE = 0.77 V) and many other reported bifunctional electrocatalysts (mostly ΔE ≥ 0.60 V). The nanoscale composite of Fe‐based single‐atom sites and nanosized layered double hydroxides endows the bifunctional electrocatalyst with high conductivity and a large active surface that afford strengthened electron conduction and ion transport pathways. Furthermore, a remarkable improvement in stability is realized following the current division principle. ZABs with the bifunctional electrocatalyst deliver a high peak power density of 198 mW cm−2 and excellent cycling durability for over 6000 cycles. Moreover, ampere‐hour‐scale ZABs are constructed and cycled under 1.0 A and 1.0 Ah conditions. This work breaks the activity record for bifunctional oxygen electrocatalysis and expands the potential of ZABs for sustainable energy storage. [ABSTRACT FROM AUTHOR]

In today's world, the efficient preparation of clean energy has become a problem for every country. Hydrogen is a very clean and easy to prepare energy source. In this paper, a hybrid materials of (Fe 6 (OH) 12 (CO 3)) and sulphide (Ni 9 S 8 /Co 9 S 8) was demonstrated as a catalytic electrode for efficient oxidation reaction in seawater and urea. The catalysts were prepared by a three-step hydrothermal-sulfuration-hydrothermal reaction, and the layered composites of hydroxides and sulfides were co-grown into nano-arrays, which exposed more reaction centers and shortened the electron transfer path. The three metal cations were also able to demonstrate different corrosion resistance and excellent adsorption properties for different environments, allowing the catalyst to present better electrochemical activity in seawater as well as in urea solution. In the oxidation reaction in urea solution (1 M KOH+0.5 M urea), the required voltage was only 1.33 V at a current intensity of 50 mA/cm2, and in the water oxidation reaction in seawater, the required voltage was only 1.47 V at a current intensity of 50 mA/cm2 for Ni 9 S 8 @Co 9 S 8 @Fe 6 (OH) 12 (CO 3). Unfortunately, the durability of the catalyst need to be improved, the current density dropped from 40 mA/cm2 to 35 mA/cm2 and then remained for 12 h. Meanwhile, the comparison of electrochemical performance tests was performed before and after the IT test, it can be clearly seen that the overall performance of Ni 9 S 8 @Co 9 S 8 @Fe 6 (OH) 12 (CO 3) decreased after the stability test, which may be related to the shedding of active species from the surface of the catalyst. As you can see through density functional theory (DFT) that Ni 9 S 8 can promote the adsorption energy of urea and Co 9 S 8 lowers the barrier to electron conduction. Many conjectures were made and confirmed in this study, and finally, it is hoped that seawater as well as industrial wastewater can be better utilized for the production of clean energy. The NiCoS@Fe 6 (OH) 12 (CO 3) catalyst present superior electrocatalytic performance in 1.0 M KOH + seawater and urea electrolyte solution. [Display omitted] • NiCoS@Fe 6 (OH) 12 (CO 3) electrodes was synthesized for the first time through hydrothermal processes. • The working potential of NiCoS@Fe 6 (OH) 12 (CO 3) electrode is only 1.33 V at 50 mA cm−2 for UOR. • The introduction of Ni 9 S 8 gives a large enhancement in the adsorption energy of urea for NiCoS@Fe 6 (OH) 12 (CO 3). [ABSTRACT FROM AUTHOR]

The mechanisms underlying the stability of the intensity imbalance between the left‐ and right‐circulating lasing modes in a GaN hexagonal microdisk resonator are investigated. Finite‐difference time‐domain simulations reveal that the imbalance is determined by the position of the point light source (seed light for lasing) inside the resonator. The coupling mechanism between the resonance modes and light from the source is clarified using numerical calculations. In addition, it is confirmed that light is highly coupled with one of the circulation modes when the source is placed off the bilateral symmetry axis of the mode near the side of the resonator, without any influence of the polarization of the source. The results indicate that the imbalance of the lasing modes observed in the experiments is determined by the position of the seed light near the side of the resonator, which must be spontaneous emission from impurities or defects, such as donor–acceptor pairs, donor‐bounded excitons, basal plane stacking faults, or the transition of free electrons in the conduction band to acceptor levels et al. [ABSTRACT FROM AUTHOR]

Co-free and Ni-rich LiNi0.95Mn0.05O2 (NM95) cathodes are expected to be widely employed in power batteries due to their high charge storage capacity and cost-effectiveness. However, the loss of Co and increase in Ni contents result in highly active surfaces and unstable structures, compromising rate capability and cyclic stability. Herein, polyaniline-polyethylene glycol (PANI-PEG) coating layer, with excellent electronic and Li-ion conductivity, is introduced on NM95 surface to enhance charge transfer properties and cyclic stability. Several material and electrochemical characterization techniques, such as XRD, SEM, EDS, TEM, XPS, 4-point probe, CV and EIS, are utilized to unveil the positive influence of PANI-PEG on electrochemical performance. The results reveal that PANI-PEG layer can promote electron and Li+ conduction of NM95 due to the excellent electronic and Li+ conductivities. Besides, PANI-PEG acts as protective layer to hinder the corrosion of electrolyte and suppress side reactions. It is revealed that NM95 cathode coated with PANI-PEG with a mass ratio of 4/6, exhibits excellent initial capacity, as high as 219.4 and 163.1 mAh/g at 1 C and 5 C, respectively, and maintains capacity retention of 94.7% (1 C, 100th cycle) and 79.0% (5 C, 200th) under cut-off voltage of 4.3 V (vs. Li/Li+). Moreover, NM95 exhibits capacity retention of 70.7% after 100 charge/discharge cycles at 1 C within voltage range of 2.7 to 4.5 V (vs. Li/Li+). These results indicate that coating electronic/Li+ conductor is effective strategy to enhance rate performance and cyclic stability of Co-free and Ni-rich cathodes. [ABSTRACT FROM AUTHOR]

[Display omitted] Low photo-induced carrier recombination rate, exceptional light absorption, and advantageous recycling performance are crucial attributes of semiconductor photocatalyst for wastewater purification. Herein, based on in-situ reaction, close-contact S-scheme bismuth chromate/bismuth oxide/ferroferric oxide@porous carbon microspheres (Cr 2 Bi 3 O 11 -Bi 2 O 3 /Fe 3 O 4 @PCs) (F-CBFP) was fabricated using alginates as precursor. Due to the abundance of functional groups on the porous carbon (PCs), Bi 2 O 3 and Cr 2 Bi 3 O 11 nanoparticles (NPs) are in situ deposited onto the highly conductive 3D magnetic porous Fe 3 O 4 @PCs microsphere surface, which not only form tight interfacial contacts and reduces interfacial potential barriers but also prevent agglomeration or shedding of the NPs during photocatalytic reactions. Moreover, density functional theory (DFT) calculations further confirm that the formation of a robust built-in electric field (BIEF) within F-CBFP prompts photo-induced electrons in the conduction band (CB) of Bi 2 O 3 to combine with holes in the valence band (VB) of Cr 2 Bi 3 O 11 , effectively constructing a S-scheme heterojunction system. Also, Fe 3 O 4 can act as a Fenton catalyst, activating the H 2 O 2 generated by Cr 2 Bi 3 O 11 under illumination. In wastewater treatment, the obtained F-CBFP shows remarkable photo-Fenton degradation (towards methyl orange (97.8 %, 60 min) and tetracycline hydrochloride (95.3 %, 100 min)) and disinfection performance (100 % E. coli inactivation), and exceptional cyclic stability. [ABSTRACT FROM AUTHOR]

It is well known that atoms of the same element in different valence states show very different chemical behaviors. Calcium is a typical divalent metal, sharing or losing both of its valence electrons when forming compounds. Attempts have been made to synthesize compounds of monovalent calcium ions for decades, but with very little success (e.g., in clusters). Pressure can result in substantial changes in the properties of atoms and chemical bonding, creating an extensive variety of unique materials with special valence states. In this study, using the ab initio evolutionary algorithm USPEX, we search for stable calcium–chlorine (Ca–Cl) system compounds at pressures up to 100 GPa. Besides the expected compound CaCl2, we predict three new compounds with monovalent Ca to be stable at high pressures, namely, CaCl, Ca5Cl6, and Ca3Cl4. According to our calculations, CaCl is stable at pressures above 18 GPa and is predicted to undergo a transition from nonmagnetic Fm-3m-CaCl to ferromagnetic Pm-3m-CaCl at 40 GPa. Ca5Cl6 and Ca3Cl4 are stable at pressures above 37 and 73 GPa, with space groups P-1 and R-3, respectively. Following these predictions, we successfully synthesized Pm-3m-CaCl in laser-heated diamond anvil cell experiments. The emergence of the unusual valence state at high pressures reveals exciting opportunities for creating entirely new materials in sufficiently large quantities for a variety of potential applications. [ABSTRACT FROM AUTHOR]

Efficient photoelectrochemical photodetectors based on WSe2/rGO have been fabricated using an annealing process. The initial performance enhancement of these devices was primarily attributed to the improved bandgap structure of WSe2 and the high carrier mobility of rGO, which facilitated an efficient transition of valence band electrons to the conduction band. Upon this understanding, a comparison between bulk WSe2 and WSe2 nanosheets (WSe2 NSs) was conducted. It was found that, at a bias voltage of 0.6 V, the photocurrent density of WSe2 NSs devices was 76% higher than that of similar bulk WSe2 devices, reaching 0.044 μA/cm2. Owing to the significant advantages of rGO, extensive testing of various WSe2 to rGO ratios was performed, identifying the precise composition that optimized photoelectric performance. Notably, under conditions of 0.5 M Na2SO4 electrolyte, 120 mW/cm2 irradiance, and 0.6 V bias potential, the devices achieved a photocurrent density of 0.64 μA/cm2, which is approximately 25.72 times higher than that of bulk WSe2 and 14.61 times more than WSe2 NSs. Moreover, the photoresponse trended upward with increasing irradiation intensity. Specifically, when the irradiation intensity was increased to 160 mW/cm2 and the bias voltage was raised from 0 V to 0.6 V, the photoresponsivity increased by 5.8 times, from 1 μA/W to 5.8 μA/W. The photodetectors constructed using the optimal WSe2/rGO ratio exhibited no significant performance degradation during a 4000-s cyclic on/off test, demonstrating their robustness under operational conditions. This study highlights the substantial potential of WSe2/rGO hybrids in enhancing the performance of photoelectrochemical photodetectors. [ABSTRACT FROM AUTHOR]

Using an impurity atom in crystal silicon as a spin-1/2 qubit has been made experimentally possible recently where the impurity atom acts as a quantum dot (QD). Quantum transport in and out of such a donor QD occurs in the sequential tunneling regime where a physical quantity of importance is the charging (addition) energy, which measures the energy necessary for adding an electron into the donor QD. In this work, we present a first-principles method to quantitatively predict the addition energy of the donor QD. Using density functional theory (DFT), we determine the impurity states that serve as the basis set for subsequent exact diagonalization calculation of the many-body states and energies of the donor QD. Due to the large effective Bohr radius of the conduction electrons in Si, very large supercells containing more than 10 000 atoms must be used to obtain accurate results. For the donor QD of a phosphorus impurity in bulk Si, the combined DFT and exact diagonalization predicts the first addition energy to be 53 meV, in good agreement with the corresponding experimental value. For the donor QD of an arsenic impurity in Si, the first addition energy is predicted to be 44.2 meV. The calculated many-body wave functions provide a vivid electronic picture of the donor QD. [ABSTRACT FROM AUTHOR]

This study delves into the relatively uncharted territory of Above Threshold Ionization in atoms, triggered by intense X-ray radiation fields. At these frequencies, the energy of a single photon far exceeds the ionization potential of valence electrons in atoms and molecules. The conditions we examine are similar to those achievable with current or future free-electron laser facilities. Under such high-energy scenarios, the onset of strong field ionization requires a shift away from the traditional quasi-classical approach. Here, we present an analytical model to characterize how the field-free ionization potential, ponderomotive energy, and photon energy govern the transition to this regime, all accounted for by means of the Keldysh and Reiss parameters. We show that both of these parameters are needed to capture the onset of strong-field behavior due to both bound state and continuum state properties. At higher X-ray intensities, we find that ionization rates deviate from the linear intensity scaling expected from lowest order perturbative processes, corresponding to channel closure and higher-order photon absorption processes. This study explores Above Threshold Ionization in atoms induced by intense X-ray radiation fields, where photon energy surpasses the ionization potential of valence electrons. The authors demonstrate that both the Keldysh and Reiss parameters are essential to capture the onset of strong-field behavior, revealing deviations from weak-field intensity scaling at higher X-ray intensities. [ABSTRACT FROM AUTHOR]

ZnS is widely used in the photocatalytic decomposition of water to produce hydrogen due to its fast electron-hole pair generation and high negative potential. However, its absorption in the visible region is poor due to its wide band gap, and it has serious photogenerated carrier recombination problems. Herein, a shallow impurity energy level was introduced by doping the ZnS lattice with Cd. Due to its presence, electrons trying to return to the valence band are trapped and excited twice, suppressing the recombination of photogenerated carriers and greatly improving electron utilization. The Cd1.5-ZnS possesses a hydrogen production rate as high as 85722.20 μmol/g, which is 17 times higher than pure ZnS. Meanwhile, Cd1.5-ZnS has a narrower forbidden band and superior visible light absorption, and the serious photocorrosion problem of ZnS has been suppressed. This study provides a viable approach for the synthesis of photocatalysts with adjustable band gaps and enhanced hydrogen precipitation efficiency. The band gap of ZnS is narrowed by doping Cd2+ into the lattice structure of ZnS. Additionally, a shallow impurity energy level is created in close proximity to the bottom of the conduction band. This level has the capacity to trap electrons returning to the valence band from the conduction band and to excite them. thereby greatly increasing the utilization of electrons and reducing the formation of electron-hole complexes. Consequently, the Cd1.5-ZnS exhibits superior photocatalytic hydrogen production performance. [Display omitted] • Shallow impurity energy levels are introduced by Cd2+ doping to give the samples the ability to capture electrons secondarily. • The samples with the optimal Zn/Cd molar ratios exhibited photocatalytic hydrogen production rates up to 85722.20 μmol/g. • The issue of the wide bandgap of ZnS has been effectively improved. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the electronic structure and optical properties of zinc-blende ZnTe, ZnS systems, ZnTe/ZnS heterojunctions, and Y-doped ZnTe/ZnS heterostructions using the generalized gradient approximation (GGA) method under the density functional theory (DFT) framework. The results show that compared to the single-component ZnTe or ZnS systems, the ZnTe/ZnS heterojunction has a smaller bandgap width and undergoes a redshift in the absorption spectrum, which is favorable for more valence band electrons to be excited by light and transition to the conduction band, thereby enhancing the optoelectronic properties of the material. After Y-doping in the ZnTe/ZnS heterojunction system, when the doping concentration is between 1.56 at% and 4.69 at%, doping Y in the ZnS layer would result in the lowest energy formation of the system. Therefore, it can be inferred that in experiments, if the doping concentration is increased beyond this range, Y atoms are more likely to be arranged in the ZnS layer. Compared with the pure ZnTe/ZnS heterojunction system, increasing the Y doping concentration results in a wider bandgap and a more prominent blue shift in the absorption spectrum. Therefore, it is possible to adjust the bandgap of the heterojunction by changing the doping concentration to fabricate heterojunction device with different photoelectric effects and luminescence properties. [ABSTRACT FROM AUTHOR]

Harnessing electronic excitations involving coherent coupling to bosonic modes is essential for the design and control of emergent phenomena in quantum materials. In situations where charge carriers induce a lattice distortion due to the electron-phonon interaction, the conducting states get "dressed", which leads to the formation of polaronic quasiparticles. The exploration of polaronic effects on low-energy excitations is in its infancy in two-dimensional materials. Here, we present the discovery of an interlayer plasmon polaron in heterostructures composed of graphene on top of single-layer WS2. By using micro-focused angle-resolved photoemission spectroscopy during in situ doping of the top graphene layer, we observe a strong quasiparticle peak accompanied by several carrier density-dependent shake-off replicas around the single-layer WS2 conduction band minimum. Our results are explained by an effective many-body model in terms of a coupling between single-layer WS2 conduction electrons and an interlayer plasmon mode. It is important to take into account the presence of such interlayer collective modes, as they have profound consequences for the electronic and optical properties of heterostructures that are routinely explored in many device architectures involving 2D transition metal dichalcogenides. Here, the authors report the observation of an interlayer plasmon polaron in heterostructures composed of graphene and monolayer WS2. This is manifested in the ARPES spectra as a strong quasiparticle peak accompanied by several carrier density-dependent shake-off replicas around the WS2 conduction band minimum. [ABSTRACT FROM AUTHOR]

Comprehending the loss mechanisms in each process (i.e., activation, oxygen and vapor diffusion, and proton and electron conduction) in polymer electrolyte membrane fuel cells is necessary to enhance their power density. However, a numerical analysis of overvoltage and resistance for each process considering heterogeneous-structure effects has not been conducted. This study extends a pre-validated heterogeneous catalyst-layer model to evaluate the overvoltage and resistance by process. During a single-cell test, impedance is measured under various operating conditions, followed by distribution of relaxation times (DRT) analysis. In the simulations, the overvoltage and resistance are separated by process to identify dominant factors. Activation and proton-conduction resistances have similar dependencies on cell voltage and relative humidity, while oxygen-diffusion resistance exhibits different dependencies. Most of the parameter dependencies are corroborated by the experimental results of the DRT analysis, thereby confirming the model's validity. This versatile model can adapt to different electrode structures and operating conditions. • A heterogeneous catalyst-layer model is extended to analyze loss mechanisms. • Dominant overvoltages are identified by separation for physicochemical processes. • Dependencies of resistances on cell voltage and relative humidity are examined. • Parameter dependencies are corroborated by experimental impedance analyses. • Local distributions reveal transition of rate-controlling processes by parameters. [ABSTRACT FROM AUTHOR]

The interfacial characteristics of platinum (Pt) metal catalysts can be systematically regulated by interacting them with electropositive metals, leading to synergistic interactions for extensive catalytic applications. In this study, an evenly dispersed polyol-synthesized iron (Fe)-promoted Pt bimetallic nanoparticle (BNPs) system was embedded in MIL-101(Cr). The PtFe 2 @MIL-101(Cr) catalyst unveiled remarkable activity (86%) and selectivity (89%) for the superior hydrogenation of the targeted C O bond of cinnamaldehyde (CAL). The exceptional hydrogenation performance can be credited to the interplay of the geometric and electronic properties arising from charge shuttling between Fe and Pt within the homogenously distributed Pt–Fe bimetallic nanoparticle system. The experimental results indicate enhanced valence electrons in the Pt d-band through the mutual synergetic interface between the Pt and Fe BNPs. Consequently, these Fe–Pt sites functioned as interfacial electrophilic and nucleophilic (Lewis acid-base) sites, enhancing H 2 activation and facilitating C O bond conversion to yield unsaturated cinnamal alcohols (COL). Additionally, the narrow pores of MIL-101(Cr) encapsulating the Pt–Fe BNPs induced steric hindrance, allowing only C O bond hydrogenation. Furthermore, the PtFe 2 @MIL-101(Cr) catalyst maintained its optimal hydrogenation performance over five cycles, demonstrating no substantial loss in either CAL conversion or COL yield, thus endorsing the universal practical applicability of the catalyst. [Display omitted] • Polyol-synthesized iron (Fe) promoted Pt bimetallic nanoparticle (BNPs) systems embedded in MIL-101(Cr). • PtFe 2 @MIL-101(Cr) showed remarkable activity in the hydrogenation of cinnamaldehyde. • The exceptional performance can be attributed to the interplay of the geometric and electronic properties arising from the Pt–Fe BNPs. • The PtFe 2 @MIL-101(Cr) catalyst maintained optimal performance over a series of five cycles. [ABSTRACT FROM AUTHOR]

Cross-luminescence (CL) in a barium fluoride (BaF2) scintillator arising from the recombination of a valence band electron and a core band hole results in a fast picosecond decay time. However, the CL emission wavelength in the vacuum ultraviolet region is difficult to detect, and intrinsically intense and slow nanosecond self-trapped exciton (STE) luminescence occurs. Herein, we report a redshift in the CL emission wavelength with high-pressure application. The wavelength of the CL emission shifted from 221 nm to 240 nm when 5.0 GPa was applied via a sapphire anvil cell. Increasing the pressure decreases the core-valence bandgap due to the downward expansion of the valence band, resulting in a decrease in the valence band minimum. The onset of a phase transition from a cubic crystal structure to an orthorhombic crystal structure at 3.7 GPa inhibited the recombination of conduction band electrons and self-trapped holes, leading to the disappearance of the STE emission. Manipulating the band structure of BaF2 by high-pressure application enables control of its luminescence emission, providing a pathway toward solving the problems inherent in this leading fast-response scintillator. Cross-luminescence (CL) in a barium fluoride arising from the recombination of a valence band electron and a core band hole, and intrinsically intense self-trapped exciton (STE) luminescence occurs. Herein, we report a redshift in the CL emission wavelength with high-pressure application via a sapphire anvil cell. Increasing the pressure decreases the core-valence bandgap due to the downward expansion of the valence band. The onset of a phase transition from a cubic crystal structure to an orthorhombic crystal structure at 3.7 GPa inhibited the recombination of conduction band electrons and self-trapped holes, leading to the disappearance of the STE emission. [ABSTRACT FROM AUTHOR]

A commercial TiO2 sample, used as received or hydrothermally treated to increase surface hydroxylation, has been functionalized by surface modification with hexadecyltrimethoxysilane. The anchoring of the silane has been characterized by means of FTIR and solid‐state NMR spectroscopies, and the grafting density was determined by thermogravimetric and N2 physisorption analyses. The silane moieties induce a partial decrease of the shielding of the valence electrons of the Ti ions at the surface, and a local modification of their crystal field, as demonstrated by XPS and UV/Vis spectroscopy, respectively. The changes in coordination and the produced oxygen vacancies result in the formation of Ti3+ defects localized in the sub‐surface region, as revealed by EPR spectroscopy. These paramagnetic centers are stabilized in the silanized samples, as the electron transfer to O2 is efficiently inhibited even under UV irradiation. However, the amount of Ti3+ centers appears to be correlated with the singlet oxygen (1O2) formation rate. Accordingly, epoxidation of limonene under UV light, chosen as a model photocatalytic reaction triggered by 1O2, occurred with higher selectivity when TiO2 was silanized and upon simultaneous NIR irradiation. These evidences suggest that in the silanized sample 1O2 may be generated through Förster‐type energy transfer from excited sub‐surface Ti3+ centers. [ABSTRACT FROM AUTHOR]

A theoretical approach of ultraviolet radiation generation via short pulse infrared laser pulse interaction with wide bandgap semiconductor is proposed. When a high intensity infrared short pulse laser incident upon it, the valence electrons to tunnel to the conduction band by laser field and generating the electron–hole pairs. The stimulated recombination of these electron–hole pairs generates the ultraviolet radiation. The concentration of the electron–hole pairs varies inside the semiconductor slab noticeably, maximum near the surface and falls sharply away from the surface due to the nonlocal effects (energy depletion of the incident laser pulse). The gain coefficient of UV laser depends on the Fermi level position, which is a function of free carrier concentration and the gain coefficient also decreases as we move away from the surface. For overall large gain of UV radiation, the thickness of the semiconductor specimen should be kept small as the gain coefficient becomes negative deeper into the semiconductor. This proposed approach will be useful for making a UV radiation source. [ABSTRACT FROM AUTHOR]

Currently, structural lithium‐ion batteries (LIBs) typically use carbon fibers (CFs) as multifunctional anode materials to provide both Li+ storage and high mechanical strength. However, due to the obvious volume expansion of CFs in lithiation process, the fiber structure suffers rapid degradation during cycling. Herein, CFs‐reinforced carbon matrix (C/C) composites are proposed as multifunctional anodes for structural LIBs for the first time. The C/C composite presents distinctive core/shell structure, in which CF as the core supplies a fast and continuous electron conduction pathway along with excellent mechanical strength, while the layered pyrolytic carbon shell accommodates the volume change of CF and provides additional ion storage. The impact of the C/C microstructure on the ion/electron transport and the Li+ storage mechanism behind such a unique hybrid structure are explored. Owing to the structural advantages of the C/C composite, the LiFePO4||C/C full cell exhibits surprising electrochemical performances at high electrode mass loadings, which are far superior to those of the present structural LIBs and even surpass the commercial LIBs at the same mass loadings. Moreover, the pouch cell presents excellent mechanical strength and mechanical‐electrochemical coupling characteristics. This work demonstrates great potential of the C/C composites as new multifunctional anodes for high‐performance structural batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Body-centred cubic (BCC) transition metals tend to be brittle at low temperatures, which poses significant challenges in their processing and major concerns for damage tolerance. The brittleness is largely dictated by cleavage fracture at crack-tips and high lattice frictions of screw dislocation cores; the nature and control of which remain a puzzle after nearly a century. Here, we introduce a crystal geometry-based, semi-empirical material index χ, the energy difference between the BCC and face-centred-cubic structures, that guides engineering of crack-tip and screw dislocation core properties. The unstable stacking fault energy on 1 1 0 planes and screw dislocation Peierls barrier have near-linear scaling with χ and the screw core transforms from non-degenerate to degenerate when χ drops below some thresholds in homogenized BCC alloys, as demonstrated in binary transition metal alloys. The index χ has its origin in crystal geometry and can be extended to finite temperatures; its value is related to entropy and valence electron concentrations, which can be quantitatively predicted by first-principles calculations and effectively tuned in solid solution alloys. The χ-model and computational approach provide a practical path to screening of favourable solutes and compositions for enhanced ductility and toughness in BCC alloys. [ABSTRACT FROM AUTHOR]

A group of EUV lines of H- and He-like ions of C provides excellent wavelength calibrations for a position-sensitive multichannel detector at a high-resolution spectrograph. We have exploited this setting for a series of spectra of highly charged Eu ions recorded at the Livermore SuperEBIT electron beam ion trap. A variation in the electron beam energy results in spectra with correspondingly staggered highest Eu ion charge states ranging from Na- through to Ni-like Eu ions. A number of spectral features can be identified from the literature, but the majority of line identifications need guidance from computations of simulated spectra on the basis of collisional-radiative models. For ions with more than two electrons in the valence shell, the typical computational results are of a markedly lower accuracy. We have applied the Flexible Atomic Code (FAC), which is capable of handling all our measured ions with reasonable accuracy. We look into the systematics of the deviation of the computed transition energies from the measured ones as a function of the electron number. [ABSTRACT FROM AUTHOR]

Using a complex of secondary and photoelectron spectroscopy methods, the effects of the implantation of In+ ions with an energy of E0 = 1 keV at different doses and subsequent annealing on the composition, electronic, and crystal structure of the GaP(111) surface were studied. It is shown that in the dose range D ≈ 5 × 1014–5 × 1015 cm−2 after annealing, nanocrystalline phases Ga0.6In0.4P are formed with surface dimensions d ≈ 10–30 nm, and at D ≥ 6 × 1016 cm−2 nanofilm–Ga0.6In0.4P with a thickness of 30–35 nm. It has been found that the band gap of nanophases (Eg ≈ 2–2.3 eV) is much larger than Eg of the film (~1.85 eV). For the first time, information was obtained on the density of state of electrons in the valence band of nanophases and nanofilm GaInP. [ABSTRACT FROM AUTHOR]

Lead–free Sn–halide perovskites (Sn–HPs) are attractive photomaterials due to their lower toxicity, and some of them with higher stability against moisture and water, compared to their Pb‐based analogous. Interestingly, Sn‐HPs can exhibit two types of optical characteristics: the first scenario is known as band‐edge electron transitions [or band‐to‐band (b‐b) emission], where accumulated electrons in the conduction band recombine with holes in the valence band, providing a close separation between the absorption edge/photoluminescence (PL) peak (small Stokes shift). The second scenario is denominated as self‐trapped exciton (STE), where intraband gap energy states are formed to trap photocarriers generated in the perovskite, producing a broadband PL and a large Stokes shift. These optical features have been suitable for developing prominent devices, but there is no consolidated explanation about the key factors influencing the emergence of b–b emission or STE in Sn‐HPs, mainly the presence of these PL mechanisms in a particular perovskite system. This review highlights how the chemical composition, structural defects, and synthetic procedures are pivotal to producing Sn‐HPs with specific b–b or STE features. This will allow the preparation of Sn‐HPs with better quality/stability, and facile modulation of their PL properties, expanding their future applicability in LCD technologies. [ABSTRACT FROM AUTHOR]

Micrometer‐sized silicon monoxide (SiO) is regarded as a high‐capacity anode material with great potential for lithium ion batteries (LIBs). However, the problems of low initial Coulombic efficiency (ICE), poor electrical conductivity, and large volume change of SiO inevitably impede further application. Herein, the vacuum thermal reduced SiOx with amorphous AlPO4 and carbon double‐coating layers is used as the ideal anode material in LIBs. The vacuum thermal reduction at low temperature forms fine silicon grains in the internal particles and maintains the external integrity of SiOx particles, contributing to mitigation of the stress intensification and the subsequent design of multifunctional coating. Meanwhile, the innovative introduction of the multifunctional amorphous AlPO4 layer not only improves the ion/electron conduction properties to ensure the fast reversible reaction but also provides a robust protective layer with stable physicochemical characteristics and inhibits the volume expansion effect. The sample of SiOx anode shows an ICE up to 87.6% and a stable cycling of 200 cycles at 1 A g−1 with an initial specific capacity of 1775.8 mAh g−1. In addition, the assembled pouch battery of 1.8 Ah can also ensure a cycling life of over 150 cycles, demonstrating a promising prospect of this optimized micrometer‐sized SiOx anode material for industrial applications. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of NH3 from N2 utilizing single-atom catalysts (SACs) is a promising strategy for industrial nitrogen fixation and chemical raw material production. In this work, single transition metals (TMs) anchored on pyrazine-based graphene (TM@py-GY) are systematically studied to screen potential electrocatalysts for the nitrogen reduction reaction (NRR) using first-principles calculations. Particularly, the descriptor φ related to electronegativity and valence electron number is selected to clarify the trend of NRR activity, realizing a fast-scan/estimation among various candidates. After a four-step screening process, WI@py-GY and MoII@py-GY SACs are screened with good structural stability, high selectivity, and high activity. Meanwhile, the thermodynamic stability of WI@py-GY and MoII@py-GY SACs is demonstrated to ensure their feasibility in real experimental conditions. Furthermore, electronic properties are also examined in detail to analyze activity origin. This work not only provides an effective and reliable method for screening electrochemical NRR catalysts with excellent performance but also provides guidance for the rational design of SACs. [ABSTRACT FROM AUTHOR]

The rational construction of interfacial nanostructures of metal/semiconductor (MS) contacted electrocatalysts has a significant impact on improving their intrinsic activities. However, MS contacts are often plagued by a strong Fermi‐level pinning effect, resulting in the formation of the Schottky barrier that affects the adsorption of hydrogen/oxygen intermediates. Herein, an Ohmic contact between metallic Ni3S2 and semiconducting NiMoN is well‐designed, which effectively reduces the electron conduction barriers. The as‐obtained NiMoN/Ni3S2 has remarkable bifunctional water electrolysis performance. At 10 mA·cm−2, the overpotential of hydrogen evolution and oxygen evolution reaction is 70 and 154 mV, respectively. Impressively, the formation of hydroxide during surface reconstruction can avoid the chlorine evolution on the catalyst surface. At an industrial process temperature of 85 °C, it takes only 340 mV for the overall seawater splitting of 500 mA·cm−2. UPS and UV‐VIS diffuse spectra combined with theoretical calculation results confirm that the self‐driven directed electron transfer derived from the Ohmic contact can induce local electron enrichment at the interface region, thus promoting the formation of *O to *OOH. This study provides important insights into the coordinated modulation of built‐in electric fields and the preparation of efficient multifunctional catalysts with a high abundance of active sites. [ABSTRACT FROM AUTHOR]

The optical and electrical properties of n-type chlorine-doped Sb2Se3 single crystals, with free carrier concentrations above 1016 cm−3 at room temperature, have been studied. The experiments reveal a strongly polarized temperature-dependent long-wavelength infrared absorption attributable to conduction band electrons within the material. For wavelengths between 1.6 and 6 μm, the room temperature absorption varies as λ 2.5 ± 0.3 , suggesting that longitudinal optical mode scattering is the dominant electron scattering mechanism. The results are most consistent with the hypothesis that electron transport in Sb2Se3 is band-like and not intrinsically limited by small-polaron self-trapping. [ABSTRACT FROM AUTHOR]

The optical and electrical properties of n-type chlorine-doped Sb2Se3 single crystals, with free carrier concentrations above 1016 cm−3 at room temperature, have been studied. The experiments reveal a strongly polarized temperature-dependent long-wavelength infrared absorption attributable to conduction band electrons within the material. For wavelengths between 1.6 and 6 μm, the room temperature absorption varies as λ 2.5 ± 0.3 , suggesting that longitudinal optical mode scattering is the dominant electron scattering mechanism. The results are most consistent with the hypothesis that electron transport in Sb2Se3 is band-like and not intrinsically limited by small-polaron self-trapping. [ABSTRACT FROM AUTHOR]

MoS 2 modification by doping transition metals is an effective way to change the Mo–S bond energy by taking advantage of the electronic variability of the d orbitals of transition metals. Herein, this study investigates the doping effect of different transition metals onto MoS 2 edge sites through DFT calculations. To screen out the metal additive effect, different transition metals were doped to the MoS 2 edge sites to see the effect on generating S vacancies that were generally regarded as the active sites. DFT simulation results proved that the ability of the valence electrons to populate the orbitals with the greatest overlap with the orientation of the edge Mo–S bond was a major factor in how simple it was to create S vacancies at the Mo-edge and S-edge sites. For the transition metals, the vacancy formation energy increases with the increase of periodic number for the same group, while decreases with the increase of the atomic weight for the same period. This implied that the upper right corner transition metals in the Periodic Table could be selected to modify MoS 2 to obtain the minimum vacancy formation energy. Therefore, nickel and cobalt are the best choice as the doping element for modifying MoS 2. [Display omitted] • The correlation between transition metal-doped MoS 2 edge sites and vacancy formation energy is unveiled. • Co and Ni doping modified MoS 2 were found to promote the generation of S-edge sites. • The correlation between electron filling in d orbitals and S vacancy formation energy is revealed. [ABSTRACT FROM AUTHOR]

Magnetic topological insulators exhibit unique electronic states due to the interplay between the electronic topology and the spin structure. The antiferromagnetic metal EuIn2As2 is a prominent candidate material in which exotic topological phases, including an axion insulating state, are theoretically predicted depending on the magnetic structure of the Eu2+ moments. Here, we report experimental results of the nuclear magnetic resonance (NMR) measurements of all the nuclei in EuIn2As2 to investigate the coupling between the magnetic moments in the Eu ions and the conduction electrons in In2As2 layers and the magnetic structure. The 75As and 115In NMR spectra observed at zero external magnetic fields reveal the appearance of internal fields of 4.9 and 3.6 T, respectively, at the lowest temperature, suggesting a strong coupling between the conduction electrons in the In2As2 layer and the ordered magnetic moments in the Eu ions. The 75As NMR spectra under in-plane external magnetic fields show broad distributions of the internal fields produced by an incommensurate fan-like spin structure which turns into a forced ferromagnetic state above 0.7 T. We propose a spin reorientation process that an incommensurate helical state at zero external magnetic field quickly changes into a fan state by applying a slight magnetic field. [ABSTRACT FROM AUTHOR]

Electro‐Fenton process stands out as a highly promising approach for generating reactive oxygen‐containing radicals to address the escalating issue of environmental pollution. However, the long‐term goal of application necessitates ongoing pursuit of high‐quality catalysts with both sufficient activity and stability. Herein, a general route is reported for large‐scale synthesis of amorphizing porous bimetallic metal‐organic framework (MOF) spheres with Zn─O─Fe structure and coordination deficiency through facile and low‐cost synthesis of ligand competition. Assisted by a coordination modulator, deprotonation of terephthalic acid is accelerated and rapid synthesis of amorphous bimetallic MOF spheres is successfully achieved at room temperature. As inactive metal Zn is introduced into metal clusters of MOFs, the cycling efficiency of Fe3+/Fe2+ is improved and a secondary building unit of Zn─O─Fe is constructed, greatly accelerating electron conduction rate. Compared to crystalline spindle cMIL‐88B(Fe2Zn) by traditional solvothermal route, amorphous aMIL‐88B(Fe2Zn) has a unique spherical porous structure with larger surface area, higher conductivity, and more exposed active sites. Endowed with unique textural and surface chemistry, aMIL‐88B(Fe2Zn) exhibits superior catalytic activity in the degradation of refractory organic pollutants. The progress offers a feasible way to rational design of iron‐based hybrid MOF materials with tunable structures and enhance properties for various applications. [ABSTRACT FROM AUTHOR]

The increasing demand for electric vehicles necessitates the development of cost‐effective, mass‐producible, long‐lasting, and highly conductive batteries. Making this kind of battery is exceedingly tricky. This study introduces an innovative fabrication technique utilizing a laser‐induced graphene (LIG) approach on commercial Kapton film to create hexagonal pores. These pores form vertical conduction paths for electron and ion transportation during lithiation and delithiation, significantly enhancing conductivity. The nongraphitized portion of the Kapton film makes it a binder‐less, free‐standing electrode, providing mechanical stability. Various analytical techniques, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and atomic force microscopy (AFM) are utilized to confirm the transformation of a 3D porous graphene sheet from a commercial Kapton film. Cross‐sectional SEM images verify the vertical connections. The specific capacity of 581 mAh g−1 is maintained until the end, with 99% coulombic efficiency at 0.1C. This simple manufacturing method paves the pathway for future LIG‐based, cost‐effective, lightweight, mass‐producible, long‐lasting, vertically conductive electrodes for lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

The global lowest-energy structures of the transition metal (TM) doped InnM (M = Mn, Fe, Co, Ni, n = 6–9) clusters are studied by using genetic algorithm combined with spin-polarized density functional theories. The low energy structures suggest that the basic building units of InnM in this size range are TM doped triangular prism and octahedron. For the lowest energy isomers, the TM atoms are endohedrally doped in In8Co/Ni and In9Fe and exohedrally doped in other clusters. Charge density analysis shows that Mn atom offers electron to the Inn frames but Co and Ni accept electrons. The spin multiplicities of the lowest energy structures are the same with those of the TM atoms for the exohedrally doped InnM clusters for n = 6, 8, and the values are smaller by one for the endohedrally doped clusters. The molecular orbitals and density of states reveal that the 4s2 electrons of the TM atoms and the 5s25p valence electrons of the In atoms form superatomic orbitals consistent with the jellium model, but the 3d orbitals of the TM interact with the superatomic orbitals in different manners and are generally singly occupied. [ABSTRACT FROM AUTHOR]

The electronic structure of NoO2 and the valence-band X-ray photoelectron spectrum (XPS) in the energy range from 0 eV to ~40 eV are calculated by the relativistic discrete variation method. Significant covalency effects are observed in NoO2, which are due to a considerable overlap of not only No 6d AO but also No 6p and No 5f AOs with oxygen orbitals. The MO histogram and scheme are derived, which enable the comprehension of features of the chemical bond nature and the structure of the XPS spectrum of valence electrons in NoO2. [ABSTRACT FROM AUTHOR]