This work examines graphene and MXene electrodes integrated with three imidazolium-based ionic liquid electrolytes for supercapacitor applications. Quantum capacitance and electric double-layer capacitance were systematically analyzed to evaluate electrode-electrolyte performance. MXenes exhibited nearly an order of magnitude higher quantum capacitance than multilayer graphene, highlighting their superior suitability. Among the electrolytes, EMIM-TCB showed limited applicability with peak capacitance confined to zero potential. In contrast, BMIM-PF 6 and BMIM-BF 4 displayed strong compatibility, particularly with MXenes, delivering enhanced capacitance across a wide potential range due to favorable structural and electrostatic interactions. Overall, the MXene-BMIM-PF 6 combination emerges as a promising candidate for high-performance supercapacitors, while the study emphasizes the critical role of interfacial engineering in the design of next-generation energy storage systems.

NiI₂ and NiBr₂ are archetypal van der Waals (vdW) triangular-lattice multiferroics that host incommensurate helimagnetic order at the lowest temperatures and undergo a transition to collinear antiferromagnetic order upon heating. Focusing on NiBr₂, we reveal that both antiferromagnetic phases exhibit a pronounced sensitivity to hydrostatic pressure. The Néel temperature of the collinear phase increases steeply at ~20 K/GPa, reaching ~100 K at 3 GPa without any indication of saturation, whereas the helimagnetic phase is completely suppressed only above ~0.8 GPa. This behavior contrasts sharply with NiI₂, in which both helical and collinear phases are strengthened until a moderate pressure of ∼6 GPa, above which the helical phase instantly disappears. Ab initio calculations identify the second-nearest interlayer exchange interaction j₂′ as the primary driver stabilizing the collinear AFM phase in NiBr₂. In addition, the in-plane exchange ratio renders the helical order in NiBr₂ considerably more fragile, enabling its suppression under relatively small pressures. These results underscore the dominant role of interlayer interactions in governing the distinct pressure responses of the magnetic phases in NiBr₂ and NiI₂. NiBr₂ and NiI₂ are van der Waals multiferroics with magnetic phase transitions from incommensurate helimagnetic order at low temperatures to collinear antiferromagnetic order upon heating. Here, the authors demonstrate that hydrostatic pressure significantly affects the antiferromagnetic phases in NiBr₂, with ab initio calculations highlighting interlayer interactions as key to stabilizing the collinear order, and reveal a contrasting pressure response in NiI₂, offering insights into pressure-induced magnetic phase control.

The increasing release of contaminants into the environment and the demand for sustainable energy solutions have prompted the exploration of advanced oxidation methods such as photo-Fenton and photoelectrochemical water splitting. Herein, hierarchical heterostructures of Cu- and Bi-codoped LaFeO3 (Bi0.05La0.95Cu0.1Fe0.9O3) (LFOBC)-decorated Ti3C2 (MXene) nanosheets were developed by a low-cost one-pot combustion approach. The optimized LFOBC/Mx-7 (Bi0.05La0.95Cu0.1Fe0.9O3/Ti3C2-7) composite demonstrated superior photo-Fenton degradation of tetracycline (TC), achieving 1.69 times higher efficiency than LFOBC and 10.65 times more efficiency than pristine LaFeO3 (LFO). This enhanced performance is attributed to strong interfacial coupling, which suppressed photoexcited carrier recombination, as confirmed by PL, TRPL, EIS, and photocurrent studies. Experimental and theoretical work function analyses revealed band bending and the formation of an Ohmic junction at the interface. Furthermore, a degradation mechanism and a reaction pathway were proposed, and the reduction in toxicity levels was identified. The LFOBC/Mx-7 catalyst also exhibited promising results for H-2 evolution with an overpotential of 156 mV vs RHE under visible-light illumination, which was 2.37 times less than that of LFOBC. These results, therefore, showcase the LFOBC/Mx composite as a multifunctional photocatalyst for both pollutant degradation and sustainable energy generation.

Cobalt-doped α-Fe 2 O 3 nanostructures show enhanced sensitivity of 1364.2 μA mM −1 cm −2 (±0.03, n = 3), selectivity, and stability for nonenzymatic cholesterol detection, with strong clinical potential supported by DFT analysis and human serum sample.

We report a systematic study of in situ cadmium (Cd) substitution at Zinc (Zn) sites in Cu2ZnSnS4 (CZTS) thin films synthesized via a scalable sol-gel route, with sulfurization carried out at 300 degrees C, 400 degrees C, and 500 degrees C. X-ray diffraction and Raman spectroscopy demonstrate that higher sulfurization temperatures along with increased Cd content progressively suppress the secondary Cu2SnS3 phase, while field-emission SEM and atomic force microscopy reveal enhanced grain growth and a smoother granular surface. UV-Vis absorption measurements show a continuous band-gap reduction from 1.43 eV in undoped CZTS to 1.20 eV at the highest Cd level, corroborated by a red shift in photoluminescence emission. X-ray photoelectron spectroscopy and density functional theory (GGA-PBE and HSE06) with orbital-projected density of states (p-DOS) analyses attribute this narrowing to localized Cd-induced states near the conduction band minimum and lattice expansion effects. Additionally, preliminary photovoltaic characterization demonstrated improved device performance for the Cd:CZTS solar cell compared to the pristine CZTS cell, exhibiting higher photocurrent density and enhanced external quantum efficiency. These results confirm that precise control of sulfurization temperature and Cd incorporation not only tailors the electronic structure and band gap but also suppresses undesirable secondary phases, offering a promising route to optimize kesterite thin films for high-efficiency photovoltaic applications.

The study focuses on the development of binary nanoalloys based on metal dichalcogenides (Sn30Se70, Ni30Te70) and quaternary nanoalloy (Ni15Sn15Se35Te35) using the melt quenching technique. The nanoalloys show extensive water splitting in fresh and real seawater. Sn30Se70-coated nickel foam achieved a benchmark current density of 349 mV for the oxygen evolution reaction (OER), while Ni15Sn15Se35Te35-coated nickel foam (NF) required only 185 mV for the hydrogen evolution reaction (HER) in 1 M KOH. The study also shows that a two-electrode system can achieve sustained total water splitting at higher current densities (1 A.cm(-2)). Modification with a CuSx layer over NF at the OER end facilitated faster kinetics and mitigated chlorine corrosion enabling direct seawater splitting at 1.26 V. Continuous direct splitting of seawater at 100 mA cm(-2) for 120 h required only 1.88 V, showing an efficiency of 92.9 % for H-2 production in real seawater.

Potassium birnessite is a remarkable material with a wider inter-planar spacing, which enables to accommodate more electrolytic ions to improve overall electrochemical performances. In this work, controlled synthesis of K(0.46)Mn(2)O4(H2O)(1.4) (HKMO) nanosheets were interconnected mesoporous networks uniformly grown on carbon cloth (CC) via a one-step hydrothermal process. Specifically, the HKMO sample synthesized at 100 degrees C for 12 h (100@HKMO-12 h) exhibited a mesoporous morphology with a large specific surface area. The binder-free 100@HKMO-12 h electrode exhibits a maximum specific capacitance of 255F g(-1) (323F cm(-3)) in 1 M NaClO4/acetonitrile electrolyte over a broad potential range of 3 V. DFT studies demonstrated the interlayer distance increased by the insertion of K+ ions into the MnO2 matrix. Bader charge analysis showed a 12.09 |e| charge difference for K-birnessite in the inter-layer region compared to the normal birnessite, supported the increase of inter-layer region in the MnO2 matrix. Significantly, the increased interlayer the distance, promoted rapid intercalation/deintercalation of Na+ ions and allowed the reversible faradic pseudocapacitance reaction to occur at a wider potential window. Moreover, the symmetric full-cell fabricated utilizing the 100@HKMO-12 h electrodes have a wide voltage of 2 V and the device delivered a maximum specific energy of 43 Wh kg(-1) (28 Wh cm(-3)) at a minimum specific power of 556 W Kg(-1) (349 W cm(-3)). Besides, the device showed an excellent capacitance retention of similar to 94 % even after 10,000 continuous charge-discharge cycles at a current of 5 A/g, indicating it is a potential candidate for next-generation sodium energy storage devices.

Herein, we adopted a new paradigm for developing a high-performance gas sensor by leveraging the mixed spinel ZnFe2O4 structure (mZFO) to enhance the adsorption of NOx molecules. Material characterization reveals the formation of the mZFO due to the cation inversion in lattice sites. The estimated value of the inversion degree is observed to shift from 0.78 to 0.39 with an increase in the calcination temperature. The mZFO nanoparticles calcined at 500 degrees C show exceptional sensing performance due to their suitable grain size (-2 times Debye length), neck diameter, and surface area. The sensing studies conducted at various NOx concentrations indicate that the sensor can detect ppb level of NOx with a detection limit of about 9 ppb at room temperature. The detailed sensing mechanism is elucidated based on the density functional theory calculations (DFT) and Bader charge analysis. The outstanding sensor performance is attributed to the formation of a mixed spinel structure, wherein the adsorption energy of NOx (--0.6 eV) in the presence of surface adsorbed oxygen is higher than that of the normal spinel structure (--0.1 eV). Furthermore, the sensor exhibited a fast response and recovery times (7 and 92 s at 800 ppb NO2), excellent stability, and selectivity. The practical suitability of the mZFO sensor was studied by analyzing the vehicle exhaust emissions. We strongly believe this work would pave a novel approach to developing a high-potential gas sensor by modifying the cation distributions in the spinel ferrites.

An excellent back contact layer is one of the key requirements for thin-film solar cells with a high energy conversion efficiency. For a highly resistive compound such as CdTe thin-film, fabrication of contact with low electrical contact resistance along with a high electron affinity is very difficult. Herein, we have thoroughly investigated the possibility of using ZnTe as a back contact layer for CdTe-based solar cells through combined experimental and first-principle studies. CdTe and ZnTe thin films were deposited on the glass substrate. Detailed structural, morphological, elemental, electrical, and optical properties are investigated through different experimental techniques. Then p-ZnTe/n-CdTe heterojunction was fabricated, and junction properties were studied. Precise electronic band-structures were obtained for CdTe, ZnTe, and CeTe/ZnTe heterojunctions. The interface properties, band edge position, and band alignments were estimated by using the HSE06 hybrid functional method. Detailed theoretical results substantiate our experimental findings.

Metal-organic frameworks (MOFs) are emerging as promising electro-catalysts for the oxygen evolution reaction (OER). The bimetallic design strategy was further adopted in MOFs to elevate the OER performance by a synergistic effect. The proximal metal-oxygen-metal bonding configuration with typical 3d(pi)-2p(pi)- 3d(pi) interaction was apparently essential for an effective electronic coupling between the metal centers. Here, we report an example of distal synergy in a bimetal-organic framework exhibiting a better OER activity than the monometallic counterparts, as well as the conventional proximal synergy. To achieve a current density of 10 mAcm(-2) , our electrodeposited bimetallic MOF, Co-Ni-(TCNQ)(2)(H2O)(2) (TCNQ = 7,7,8,8-tetracyanoquinodimethane), on a glassy-carbon electrode required an overpotential value of 220 mV. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed distinctive electronic coupling between the Co(II)-3d(7) and Ni(II)-3d(8) centers, despite being 9 & Aring; apart, leading to an overall charge delocalization in the structure via TCNQ.

A class of II–VI semiconductors, especially CdTe, is a highly photo‐reactive compound that would be suitable for photovoltaic applications. However, being a highly resistive material, CdTe produces considerable contact resistance and drastically reduces the efficiency of photovoltaic devices. Introducing a back surface field layer at the contact region may significantly improve the device's performance. This work investigates the suitability of using ZnSe and CdSe layer as a back‐surface‐field layer in CdTe‐based solar cells through accurate electronic structure calculations using the hybrid‐density functional theory method. The calculations show that both ZnSe/CdTe and CdSe/CdTe behave as type‐II heterojunctions with band gaps of 2.0 and 1.1 eV, respectively. The Mulliken electronegativity method is used to determine the correct band edge positions concerning the vacuum level for all the pristine semiconductors and their interfaces. Calculation shows that a significant charge redistribution in the interface leads to the formation of an effective local field near the contact region for both ZnSe/CdTe and CdSe/CdTe heterostructures. This local field may help to separate the photogenerated electron–hole pairs in the active layer by pushing the opposite charges into the two different sections of the heterojunction. Additionally, the heterojunctions also exhibit better light‐absorption characteristics in the visible light range.

In recent times, ZnS and ZnSe thin films are drawing tremendous attention towards opto-electrical devices due to their optimal wide band gap energy. By alloying ZnS and ZnSe films to obtain ZnSxSe1_x thin films, the band gap of the ZnSxSe1_x film can be tuned to a value according to the device requirements. Herein, ZnSxSe1_x thin films were deposited on pre-cleaned glass substrates using a thermal evaporation system and the various properties of the obtained thin films were analyzed by altering the percentage of sulfur concentration in the films. The XRD analysis illustrated that the prepared films are polycrystalline in nature and oriented along cubic (111) plane. The deviation of (111) preferential peak position with composition 'x' along the absence of any secondary peaks confirms the formation of ternary ZnSxSe1_x thin films. DFT analysis verifies the formation of pristine ZnSxSe1_x alloy system. FESEM micrographs displayed that the ZnSxSe1_x thin films do not have any cracks or pinholes. EDAX analysis of the films revealed the existence of Zn, Se and S in an appropriate quantity. Optical analysis revealed the effective band gap tailoring of ZnSxSe1_x thin films. The band gap of the ZnSxSe1_x thin films in-creases from 2.59 eV to 3.38 eV as the composition 'x' varied from 0 to 1 and band composition was determined using the DOS plot obtained using VASP.

A Ce/Ti-based bimetallic 2-aminoterephthalate metal-organic framework (MOF) was synthesized and evaluated for photocatalytic reduction of CO2 in comparison with an isoreticular pristine monometallic Ce-terephthalate MOF. Owing to highly selective CO2 adsorption capability, optimized band gaps, higher flux of photogenerated electron-hole pairs, and a lower rate of recombination, this material exhibited better photocatalytic reduction of CO2 and lower hydrogen evolution compared to Ce-terephthalate. Thorough probing of the surface and electronic structure inferred that the reducibility of Ce4+ to Ce3+ was due to the introduction of an amine functional group into the linker, and low-lying Ti(3d) orbitals in Ce/Ti-2-aminoterephthalate facilitated the photo-reduction reaction. Both the MOFs were calcined to their respective oxides of Ce1-xTixO2 and CeO2, and the electrocatalytic reduction of CO2 was performed over the oxidic materials. In contrast to the photocatalytic reaction mechanism, the lattice substitution of Ti in the CeO2 fluorite cubic structure showed a better hydrogen evolution reaction and consequently, poorer electroreduction of CO2 compared to pristine CeO2. Density functional theory calculations of the competitive hydrogen evolution reaction on the MOF and the oxide surfaces corroborated the experimental findings.

Synthesis and characterization of thin-film based photovoltaic materials attract with great research interest for the past few years as the efficiency of the photovoltaic cell can be improved systematically with a proper functionalization of the films and making multilayers. We have synthesized Cu-doped CdTe thin films with different doping concentrations using the PVD technique. The structural, morphological, and optical properties of synthesized films were carefully investigated. Our study shows that all the prepared films are polycrystalline with a cubic structure. The morphological studies (SEM) reveal that all the films are crack and pinhole-free. The composition and stoichiometry of the film were confirmed by energy dispersive spectroscopy (EDS) study. The optical characterization of the samples is performed by using UV–VIS -NIR spectrometer. The result shows interesting optical behavior of the film suitable for solar cell applications.