We employ density functional theory (DFT) to investigate how Stone-Wales (SW) defects modulate the electronic and electrochemical properties of two-dimensional silicon carbide (SiC) monolayer for sodium (Na)-, potassium (K)-, and magnesium (Mg)-ion batteries. The SW-SiC structure is energetically feasible and dynamically stable, with defect formation reducing the bandgap by ~ 70% and enhancing electronic conductivity. Compared to pristine SiC, SW-SiC exhibits stronger adsorption for Na (- 0.89eV) and K (- 1.52eV) with pronounced charge transfer at the adatom-substrate interface. Theoretical capacities of 300 and 600mAh g⁻1 for Na and K, respectively, are achieved, along with low diffusion barriers (0.88eV for Na, 0.54eV for K) and favorable open-circuit voltages (0.44V, 0.70V). Minimal structural distortion upon ion insertion confirms structural stability. These results elucidate the defect-property interplay in 2D SiC and establish SW defect engineering as a viable approach for optimizing condensed-phase anode materials beyond lithium systems.

The complete mechanism for the reaction of β-enamino diketone (BED) with methylhydrazine in H2O/MeOH and acetonitrile is elucidated via state-of-the-art quantum chemical calculations. Our results show that the mechanism branches into multiple pathways with distinct energetic profiles, leading to a product distribution governed by a delicate balance of electronic effects. The initial branching point is determined by which the nitrogen atom of the asymmetric methylhydrazine (NH2 or NHMe) attacks the BED β-carbon. Following the elimination of HNMe2, a cyclization step occurs, where the remaining methylhydrazine nitrogen attacks one of two distinct carbonyl carbons, leading to a product distribution, where three of four possible regioisomers are observed experimentally. The activation energy for this cyclization is influenced by the electronic properties of the substituents on both the carbonyl carbon (methoxycarbonyl or chlorophenyl) and the nucleophilic nitrogen (H or Me). Critically, this cyclization is contingent on a proton transfer from nitrogen to the carbonylic oxygen, promoted by a proton transfer catalyst (PTC). In H2O/MeOH, the protic solvent molecules act catalytically, whereas in acetonitrile, an acidic nitrogen center, as in methylhydrazine or dimethylamine, is required. The importance of the proton transfer catalyst is confirmed by experimentally determined product ratios of the reaction in acetonitrile with catalytic acetic acid.

The introduction of N-heteroaromatic rings like pyridine and pyrrole into the helicene scaffold can significantly impact the electronic properties, redox potentials and coordination abilities of helicenes, which lead to diverse and intriguing applications for these chiral azahelicenes. However, methods for catalytic enantioselective synthesis of these compounds, especially those with N-heterocyclic moieties, remain largely underdeveloped. Herein, we present an efficient method for catalytic enantioselective synthesis of azahelicenes bearing a pyrrolo[2,3-c]pyridine moiety through chiral phosphoric acid-catalyzed asymmetric Pictet-Spengler reaction coupled with in-situ dehydrogenative aromatization. Moreover, the utilization of isatins in this process resulted in an unexpected oxidative ring-expansion rearrangement, yielding azahelicenes with an additional fused seven-membered heterocyclic structure. Various control experiments were performed to elucidate the reaction mechanism, revealing a dynamic kinetic resolution process. Diverse derivatizations have been studied to showcase the utilities of this method, which revealed a primary amine-containing helicene derivative that acts as a highly stereoselective helically chiral organocatalyst. Furthermore, these chiral azahelicenes exhibit potent photophysical and chiroptical properties, further underscoring the significance of this method.

ABSTRACT In the development of advanced nuclear fuels, we investigated how transition metals (TM = Nb, Ta, Zr) affect the thermodynamic and electronic properties of thorium monocarbide (ThC) using first‐principles calculations. We modeled six ternary carbide compositions (Th 1− x TM x )C with x = 0.1 and 0.2 to predict key properties including heat capacity, entropy, Gibbs free energy, and bulk modulus across 0 K–1800 K. Results show that (Th 1− x Ta x )C has the lowest equilibrium energy and smallest volume, whereas (Th 1− x Zr x )C maintains the highest thermal conductivity and mechanical rigidity. Notably, (Th 0.8 Ta 0.2 )C exhibits significant phonon scattering and structural softening. Bonding charge density analysis reveals strong covalent Nb‐C bonds and intensive Zr‐C interactions, providing critical atomic‐level insights to accelerate development of next‐generation Th‐based nuclear fuels.

The axial-bonding ability of aluminum(III) porphyrin has been employed to construct two covalently linked homodimer systems. The center-to-center distance between the two porphyrins, which are connected via an oxalic bridge is ∼6.90Å. Unlike most other meso-substituted porphyrins, which have aromatic substituents, the Al porphyrins were decorated with propyl or heptyl side groups to tune their electronic properties. Further, the Lewis acidity of the Al center was exploited to coordinate the Lewis base, imidazole, appended to the electron acceptor, C60, to construct a self-assembled supramolecular homodimer-C60 donor-acceptor conjugate. Steady state optical studies show that the exciton coupling between porphyrins is weak, and time-resolved electron paramagnetic resonance (TREPR) measurements in the glass phase indicate that the triplet state of the dimer remains localized. When C60 is coordinated to the monomers and dimers, femtosecond and nanosecond transient absorption studies and TREPR measurements show that electron transfer between the porphyrin and fullerene occurs. Despite the weak coupling between the two porphyrins of the dimer, the presence of a second porphyrin enhances both the yield and lifetime of the charge-separated state. Remarkably, the resulting charge-separated lifetimes found to be between 2-5µs in the investigated reaction center mimics.

Selenium-integrated metal-organic frameworks and their derived materials (Se-MOFs) represent a transformative class of materials that synergistically combine the structural tunability of MOFs with Se's unique electronic, catalytic, and biological properties. By confining Se within MOF architectures, Se-MOFs effectively mitigate key challenges such as aggregation, polyselenide dissolution, and limited stability, while exhibiting enhanced redox activity, electronic conductivity, catalytic efficiency, and stimuli-responsive behavior. These features enable Se-MOFs to achieve high performance in alkali-metal-selenium batteries and supercapacitors while also enhancing electrocatalytic processes like oxygen reduction, oxygen evolution, and hydrogen evolution reactions. Beyond energy applications, Se-MOFs offer tunable porosity and surface functionality for controlled drug delivery, anticancer, and antioxidant effects, alongside promising environmental remediation capabilities. This review critically surveys the design strategies, synthetic methodologies, structure-property relationships, and application-specific advantages of Se-MOFs, addressing challenges in toxicity, scalability, and functional optimization. By consolidating mechanistic insights and recent advances, it provides a roadmap for rationally designing Se-MOFs and expanding their impact across energy, catalysis, biomedical, and environmental technologies.

Abstract Perovskite oxides, recognized for their excellent ambient stability, tunable synthesis, and wide bandgap characteristics, show promising applications in electronic and optoelectronic devices as semiconductor channels and transparent conductive electrodes. This work employs first-principles density functional theory (DFT) to systematically investigate the influence of hydrostatic pressure (0-60 GPa) on the structural, electronic, mechanical, and optical properties of perovskite-type LiTaO₃. Upon increasing the pressure to 35 GPa, discontinuous variations in lattice parameters and volume, combined with a near-zero formation enthalpy (ΔH ≈ 0), clearly indicate a structural phase transition from the R3c to the Pnma phase. The absence of imaginary phonon modes and the fulfillment of mechanical stability criteria confirm the thermodynamic and mechanical stability of both phases. Analysis of elastic properties reveals that the high-pressure Pnma phase exhibits more pronounced anisotropy. Electronic structure calculations show that the R3c phase at 0 GPa has a direct bandgap of 3.205 eV, which decreases only slightly under pressure, while at the transition pressure of 35 GPa, the Pnma phase adopts an indirect bandgap of 1.26 eV. This reduced bandgap enhances light absorption in the visible to near-infrared range, suggesting potential applications in solar cell absorber layers and near-infrared LEDs. The phase transition also induces characteristic changes in the optical spectrum: the double-peak feature near 7.5 eV merges into a single peak, and all major spectral features exhibit systematic blue shifts and enhanced intensities.Physica ScriptaThese optimizations highlight the potential of LiTaO₃ for vacuum ultraviolet applications, such as spacecraft monitoring and high-resolution lithography. The evolution of elastic properties with pressure is also distinctive: in the R3c phase (0-34 GPa), the bulk modulus varies non-monotonically, while shear and Young's moduli decrease, indicating shear softening. At 35 GPa, elastic instability emerges, accompanied by anomalous negative values in shear and Young's moduli. Beyond this point, the Pnma phase shows markedly increased moduli, indicating improved rigidity and ductility. Elastic anisotropy analysis further reveals enhanced spatial heterogeneity under pressure. This study elucidates the phase-transition-mediated mechanical evolution of LiTaO₃, underscoring its potential in flexible electronics.

This article seeks to develop new antioxidant agents to address the rising prevalence of oxidative stress-associated disorders. This research outlines a high-yielding synthetic approach to functionalized pyrazolo[5,1-b]quinazoline tethered 1,2,3-triazole derivatives 7(a-x) using L-proline as a catalyst under microwave irradiation. The synthesized compounds were evaluated for their in vitro antioxidant activity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical as well as hydrogen peroxide (H2O2) scavenging assays. In all assays, compounds 7a, 7b, 7c, 7d, 7m, 7n, 7o, and 7p exhibited significantly greater antioxidant activity compared to the reference standard, ascorbic acid. Molecular docking study reinforced the experimental findings, showing that the compounds engage in multiple binding interactions within the active sites of both enzymes. Additionally, density functional theory (DFT) analysis was also performed to examine the electronic and molecular properties of the compounds, revealing strong agreement between theoretical predictions and experimental results. Overall, the results highlight these derivatives as promising lead candidates for antioxidant drug development, supported by robust evidence from molecular docking and DFT analyses.

This work reports the design and optimization of a CH3NH3SnIxBr3-x (0 ≤ x ≤ 3)-based solar cell, with the primary study focusing on the impact of the "I" concentration in CH3NH3SnIxBr3-x material on the device output parameters in terms of short circuit current density (JSC), open circuit potential (VOC), fill factor (FF), and power conversion efficiency (PCE). This study is backed by a brief discussion using density functional theory (DFT) analysis of the structural and electronic properties of the perovskite material. The solar cell achieved optimal performance when the value of x in CH3NH3SnIxBr3-x was set to 3, meaning that CH3NH3SnI3 served as the absorber layer. With CH3NH3SnI3 as the absorber, the solar cell was further refined by adjusting the absorber thickness, doping density, and both internal and interfacial defect densities. The optimized solar cell attained a PCE of ∼34.05% at a thickness of 1 μm and a doping density of 3.2 × 1015 cm-3, assuming no defects. When internal defects were factored in, the PCE decreased to ∼32.33%, with a JSC of 34.69 mA/cm2, a VOC of 1.13 V, and a FF of 82.23%. Introducing interfacial defects (1015 cm-2) led to adjustments in the values, such as JSC = 34.05 mA/cm2, VOC = 1.038 V, FF = 86.72%, and PCE = 30.66%.

A series of heptagon-embedded multiple helicenes was synthesized in which the heptagon subunit was fused to the π-framework through Knoevenagel condensation reactions. By controlling the conditions of the cyclodehydrogenation (Scholl) reactions, different fused chiral and twisted PAHs were accessible. The optical and electronic properties of all products were investigated by UV-vis, fluorescence spectroscopy, and cyclic voltammetry. One member of the series displays an unusual anti-Kasha-like fluorescence emission. In addition, all the enantiopure [6]helicenes were separated by chiral HPLC and characterized by circular dichroism spectroscopy.

The study of nanoclusters (NCs) has provided invaluable insights into the interactions among small assemblies of atoms, where their size encapsulates vital information about atom-atom synergies that govern morphology, defects, and electronic states. The precise tuning of NC size has become a pivotal factor in optimizing their performance. Evolving in tandem with other ultra-high vacuum (UHV) techniques over recent decades, the gas-phase condensation technique has emerged as a remarkable approach to synthesize solvent-free and ligand-free NCs with tailored size distributions. This review provides a dual focus on the formation and size control of NCs through the gas-phase condensation technique, elucidating its advantages and limitations primarily through the use of magnetron-based sputtering sources, as well as on the size-dependent physical, chemical and electronic properties of NCs in their diverse applications. The capacity to engineer NCs with precision down to the number of atoms has ushered in a new era of transformative impacts on chemistry, materials science, and beyond. The precise control of NC size and composition has opened new opportunities for tailoring their size-specific properties for specific applications, thereby harnessing their full potential to meet the grand challenges of the rapidly evolving world of nanotechnology.

While azobenzene has been studied extensively for its single-molecule charge transport properties, its complexation with guest ring molecules may significantly influence charge transport that is not yet well understood. In this work, we study the influence of host-guest interactions between α-cyclodextrin (α-CD) and azobenzene on the single-molecule conductance of azobenzene in an aqueous solution. Hydrophobicity of azobenzene drives its formation of an α-CD/azobenzene host-guest complex with α-CD in water, which is indicated in our nuclear magnetic resonance and ultraviolet-visible spectroscopy experiments. We see a modest ∼3.5-fold conductance increase for amine-terminated azobenzene upon host-guest complex formation. Notably, this enhancement displays progressive conductance attenuation over time, finally down to the conductance value of the azobenzene junction, which we attribute to the declining number of formed complexes in the aqueous solution as α-CD aggregates with time. In contrast, for amine-terminated stilbene (backbone modification) and for thiomethyl-terminated azobenzene (linker modification), no conductance change is seen with the addition of α-CD. First-principles simulations suggest that the lowest unoccupied molecular orbital (LUMO) of the α-CD/amine-azobenzene complex junction is at a lower energy than that of amine-azobenzene, thereby suggesting a possible conductance increase, agreeing with our experimental observations. Taken together, this study provides valuable perspectives on the intricate roles that the host-guest interactions play in regulating the molecular electronic properties.

As promising candidates for next-generation display technologies, perovskite light-emitting diodes (PeLEDs) continue to face bottlenecks of lower external quantum efficiency (EQE) and poor operational stability in the blue light region. Increasing the chlorine content represents a straightforward strategy for widening the bandgap to achieve blue emission. Nevertheless, the limited solubility of chlorine sources often leads to incomplete halogen incorporation, high defect density, and thus difficulty in obtaining pure blue emission with wavelengths shorter than 470 nm. In this study, we introduce a metastable precursor solution strategy that effectively modulates the colloidal chemistry to suppress CsCl precipitation, reduce colloidal size, and minimize halogen vacancies. These synergistic effects improve film coverage, enhance crystallinity, and lower the defect-state density. As a result, the optimized pure-blue PeLEDs achieve a peak EQE of 6.6% and exhibit stable electroluminescence at 468 nm. This work elucidates the fundamental mechanism through which precursor colloidal dynamics dictate the crystalline and electronic properties of perovskite films and provides a practical approach for optimizing the performance of mixed-halide perovskite optoelectronic devices.

Monitoring and discrimination of molecular behavior in isomers remain a longstanding challenge due to similar chemical compositions, although they have functionally critical differences. Due to the consistent demand for molecular design/structural analysis in research fields and reaction/quality control in industrial fields, the identification of isomeric pairs is essential. However, conventional analytical techniques, including nuclear magnetic resonance and mass spectrometry, require destructive processes or large-scale sample volumes, limiting their applicability to on-chip or simple analysis with accessibility. Here, we propose a graphene-integrated terahertz metasurface platform that enables nondestructive and on-chip constitutional isomer discrimination, along with monitoring over interfacial molecular behavior with a nanogram scale limit of detection. By covering a graphene layer onto a nanoslot cavity array of the metasurface, a floated graphene monolayer can be utilized as an active probing pad with the assistance of extreme terahertz field confinement. With high sensitivity toward the interfacial state of the graphene surface, constitutional isomers with different electronic properties can be comprehensively distinguished via both the graphene-analyte interaction rate and the graphene conductivity change. The proposed platform features label-free isomer discrimination and interfacial interaction monitoring through a one-shot process implemented within a 6 mm square compact metasurface using under 20 μL of sample solution. This configuration benefits from compatibility for electrical measurement in addition to optical analysis in a nondestructive manner, with promising potential for molecular isomer characterization and behavior tracking.

Analysis of the electronic and magnetic properties of half-metallicity at the MnZrSi surfaces and MnZrSi/CdSe (111) interface

Ab initio calculation of transition properties and infrared absorption spectrum of the NaS molecule.

This paper systematically studied the structural, mechanical, electronic, and optical characteristics of cubic KZnX3 (X = F, Cl, Br, and I) perovskites through the density functional theory (DFT) in the Quantum Espresso framework. Structural optimization and stability analyses confirm that all compounds crystallize in the cubic Pm-3m phase and are thermodynamically, mechanically, and dynamically stable. Elastic constants indicate that the materials are anisotropic and ductile in nature. Calculations of Debye temperatures show a systematic decrease of 402 K (KZnF3) to 158 K (KZnI3), which is related to the increasing mass of halogen and its impact on the rigidity of the lattice. Electronic structure calculations show that all compounds are indirect bandgap semiconductors, with bandgaps systematically decreasing from 4.24 eV (KZnF3) to 0.86 eV (KZnI3) at the HSE06 level, enabling tunable semiconducting characteristics for optoelectronic applications. The analysis of the density of states and charge density indicates that the bonding between Zn and X is mixed ionic and covalent and that the bonding between K and X is mostly ionic. Calculations of optical properties show an increase in polarizability, absorption, refractive index and plasmonic response when heavier halogen is used, highlighting the potential of KZnX3 perovskites for photovoltaic and optoelectronic devices. Overall, halogen substitution in KZnX3 provides an effective strategy for tailoring electronic and optical properties.

Two-dimensional (2D) van der Waals (vdW) ferromagnetic heterostructures offer a nondestructive strategy for engineering and modifying the magnetic and electronic properties of 2D materials. Realizing large-area, atomically thin 2D vdW ferromagnets with Curie temperature (Tc) above room temperature remains a key challenge due to the limited size, uncontrolled thickness, and suppressed magnetism of existing materials. Here, we report the wafer-scale growth of layer-controlled CrTe2-containing vdW heterostructures via a "high-to-low" temperature growth strategy. This approach enables the precise fabrication of diverse heterostructures with atomically sharp interfaces, controlled layer numbers, and excellent structural uniformity across 4 in. wafers. Systematic characterizations reveal robust proximity-induced interfacial magnetic enhancement, achieving a Tc of up to 300 K in WTe2/6L CrTe2 and PtTe2/6L CrTe2 wafers through large spin-orbit coupling. This work provides a scalable pathway for constructing high-quality 2D magnetic vdW heterostructures and provides a rational design framework for future 2D spintronic devices.

Neuromorphic computing, inspired by the architecture of the human brain, offers efficient and scalable hardware solutions for AI applications. Antiferroelectric (AFE) materials are promising for such applications due to their large number of intermediate polarized states. In this study, we investigate monolayer CuCrP2S6 (CCPS), a layered material that has two unique AFE (I and II) phases. The AFE-II phase allows ferroelectric (FE) domains to be as small as a single unit cell, addressing challenges such as cycle-to-cycle and device-to-device variations, as well as the limited number of intermediate states in neuromorphic systems. The material exhibits a unique response to mechanical strain, enabling modulation between the AFE-II and AFE-I phases. Additionally, depending on whether the applied strain is compressive or tensile, the FE domain patterns can be tuned. Applying tensile strain along the a-axis results in FE domains extending along the b-axis, whereas applying compressive strain along the a-axis leads to domain continuation along the same a-axis, forming stripe-like FE domains. Band structure analysis reveals significant anisotropy in the electronic properties of the AFE-I phase, while magnetic anisotropy is also present, albeit with a smaller magnitude. This anisotropy enables phase and FE domain pattern identification using electrical properties. Additionally, we demonstrate possible polarization switching pathways through different AFE states, outlining the broad landscape of available intermediate FE states and domain kinetics inherent to CCPS. These findings highlight the untapped potential of not only CCPS but also other AFE materials for application in next-generation neuromorphic and electronic systems, offering new avenues for device functionality and design.

The growing demand for renewable energy necessitates the development of sustainable, high-performance, eco-conscious solar cells. This research proposes a novel lead-free dual-absorber perovskite solar cell (DAPSC) utilizing Ca3SbI3 as the top absorber and Ba3SbI3 as the bottom absorber layer. The device structure, Al/FTO/SnS2/Ca3SbI3/Ba3SbI3/CBTS/Au, was analyzed by employing SCAPS-1D to evaluate photovoltaic performance under standard AM1.5G illumination. The dual-absorber configuration exhibited a considerably improved power conversion efficiency (PCE) of 36.03%, short-circuit current density (Jsc) of 32.18 mA cm−2, open-circuit voltage (Voc) of 1.305 V, and fill factor (FF) of 85.84%, outperforming single-absorber perovskite solar cells. We further employed a Random Forest Regression (RFR) model to forecast the proposed device performance. We found that the machine learning (ML) model achieved excellent predictive performance with an average coefficient of determination (R2) of 0.9635, mean absolute error (MAE) of 0.4506, and root mean square error (RMSE) of 0.6253. Moreover, feature importance analysis validated by SHAP (Shapley Additive exPlanations) summary plots and correlation matrices revealed that operating temperature and absorber layer parameters (doping, thickness, and defect level) were the most critical factors influencing photovoltaic performance, while electron and hole transport layer properties also played significant roles. These outcomes reveal that the proposed lead-free DAPSC model presents enhanced performance, stability, and environmental compatibility for photovoltaic applications.