Background: Reconfigurable metamaterial absorbers are increasingly important for microwave stealth, radar cross-section (RCS) control, electromagnetic compatibility, antenna isolation, and adaptive electromagnetic skins, but many reported absorbers still trade bandwidth against angular stability or tunability. Objective: This paper designs and evaluates a multi-layer hybrid metamaterial absorber integrating a patterned copper resonator, resistive frequency-selective surface, dielectric spacers, a metallic ground plane, and tunable VO₂/graphene-inspired conductivity states for wide-angle microwave absorption, RCS reduction, and optoelectronic reconfigurability. Methodology: Because no laboratory dataset was supplied, a clearly labelled simulated primary dataset was generated for demonstration from a physically constrained full-wave surrogate protocol covering 2,550 frequency-angle-polarization-bias-state observations over 8–18 GHz. The dataset included S11, S21, absorption, normalized impedance, field intensity indices, surface-current indices, RCS reference/proposed values, bandwidth, peak absorption, tunability range, and angular stability. Statistical validation used descriptive statistics, Shapiro–Wilk normality testing, paired comparative testing against a non-reconfigurable baseline, one-way and factorial ANOVA, Tukey post-hoc comparison, regression, Pearson correlation, effect-size estimation, and simulation-to-measurement error analysis on a measurement-surrogate subset. Findings: The proposed design achieved a mean simulated absorption of 91.95% across all conditions, a mean >90% absorption bandwidth of 6.69 GHz, a peak absorption confidence interval of 98.89–99.19%, and a mean RCS reduction of 16.00 dB relative to a metallic reference. The paired comparison against the baseline absorber was statistically significant (p < 0.001; Cohen’s d = 7.63). Novelty: The paper combines hybrid multi-layer impedance matching, tunable material-state control, wide-angle TE/TM evaluation up to 60°, RCS reduction assessment, and formal statistical validation in one publication-oriented framework. Applications: The design is relevant to adaptive stealth surfaces, antenna platforms, smart microwave skins, reconfigurable surfaces, and tunable optoelectronic sensing interfaces.

This study focuses on the structural and optical modifications in ZnO nanoparticles upon Mg doping. The nanoparticles were synthesized through a sol-gel route using nitrate precursors, yielding polycrystalline material. The X-ray diffraction (XRD) followed by Rietveld refinement confirmed the formation of the wurtzite phase of ZnO nanoparticles without any additional impurities, suggesting successful substitution of Mg2+ at Zn2+ lattice sites. The average crystallite size, calculated using the Debye–Scherrer relation, was found in the range of ~25–40 nm and exhibited a gradual increase in the crystallite size with Mg content up to 6% doping. The decrease in particle size with increasing Mg doping was observed through field emission scanning electron microscopy (FESEM) images. Fourier transform infrared microscopy (FTIR) spectra further validated the ZnO lattice framework and indicated the preservation of tetrahedral coordination around oxygen. UV–Vis absorption studies revealed slight band gap variations, characterized by an initial blue shift upon Mg incorporation followed by a minor red shift at higher doping levels. These results demonstrate that controlled Mg substitution offers a pathway to tune the structural coherence and optical response of ZnO nanomaterials.

Pure ZnO and Na-doped ZnO nanoparticles (Na = 1%, 3%, and 5%) have been synthesized by the simple co-precipitation method. XRD patterns and Rietveld refinement confirm the P63mc space group corresponding to the single-phase hexagonal wurtzite crystal structure of ZnO. SEM micrographs show a spherical particle structure with an average particle size of 40–60 nm in all prepared samples. XPS studies reveal the existence of defect-level states and oxygen vacancies (Vo’s) in all the synthesized samples; Vo’s increase with Na doping. UV-Visible spectroscopy indicates a decrease in the energy band gap from 3.23 eV to 3.19 eV with increasing Na concentration for Na-doped ZnO nanoparticles. The Photoluminescence spectroscopy results confirm the presence of defect-level emissions and lattice defects, including Vo’s, in all the prepared samples, and these increase with increasing Na doping. FTIR spectra confirm the presence of functional groups and chemical bonding at the ZnO interface. In the FTIR spectra, a weak absorption peak around 670 cm−1 confirms the presence of Na in the ZnO matrix, and the strong peak around 532 cm−1 indicates the formation of hexagonal wurtzite ZnO nanoparticles. VSM measurements show room-temperature ferromagnetism (RTFM) in all Na-doped ZnO nanoparticle samples. RTFM increases with enhancing Na-doping and increasing Vo’s, and a maximum saturation magnetization of 54.73 × 10−4 emu/gm was found in the 5% Na-doped ZnO sample. The origin of RTFM in the Na-doped ZnO system may be Vo’s and defects. The RTFM in the Na-doped ZnO system may be a suitable material for future spintronic applications.

In this study, chemical bath deposition method was used to deposit undoped and Mn-doped ZnS thin films, which possess hexagonal wurtzite phase with bullet-like nanorod structure. Absorption spectroscopy indicates the shifting and broadening of the absorption edge, which reduced the band gap from 3.10 eV for undoped ZnS (A1) to 2.39 eV and 2.08 eV for A2 and A3 Mn-doped thin films. The PL emission spectra show the Mn-assisted emission peaks between 570 nm and 640 nm. Moreover, X-ray photoelectron spectroscopy confirms Zn2+ and S2- species and Mn atoms in the ZnS matrix. The fabricated heterojunctions respond swiftly and reliably under the illumination of visible and ultraviolet lights. We have observed the shortest rise time (tau r) and decay time (tau d) as 0.103 s - 0.096 s, whereas higher sensitivity (S) and detectivity (D*) were observed following Mn atom doping, with best values of 28.58 and 0.39 & Cross;1010 Jones respectively.

Supercapacitors offer high power density, fast charge-discharge capability and long cycle life but often suffer from low capacitance and poor interfacial contact in conventional slurry-cast electrodes. Here, we report a binder-free NiCoSe4@NiCo layered double hydroxide (LDH) heterostructure fabricated directly on nickel foam, where Ni foam serves simultaneously as the current collector and in situ Ni2+ source. This strategy enables the controlled growth of vertically aligned NiCoLDH nanoneedles with intimate, continuous interfacial contact, unlike weak adhesion observed in conventionally synthesized double salt NiCoLDH (DS-NiCoLDH) electrodes. As a result, NiCoLDH-10 achieves an areal capacitance of 4228 mFcm- 2, much more than that of DS-NiCoLDH (2236 mFcm- 2), along with reduced charge-transfer resistance (1.1 S2 vs 2.1 S2). Mild selenization forms a mixed NiCoSe4/NiSe shell on the NiCoLDH core, leading to enhanced redox activity and outstanding areal capacitance of 7150 mFcm- 2. Structural and spectroscopic studies confirm the formation of an integrated selenide/LDH heterostructure with retained hydroxide features and improved charge transport. The NiCoSe4@NiCoLDH//Activated Carbon (AC) asymmetric device delivers 738.5 & micro;Whcm- 2 at 900 & micro;Wcm- 2 and maintains 402.5 & micro;Whcm- 2 even at 9000 & micro;Wcm- 2, along with 102% capacitance retention after 15,000 cycles and practical capability to power small electronics, offering a scalable route toward high-performance supercapacitors.

A first-principles study of the electronic, optical, and thermodynamic properties of thallium ytterbium selenide (TlYbSe2) is carried out using density functional theory. Spin-polarized calculations within the PBE-GGA, TBmBJ, and DFT+U frameworks are performed to examine the influence of strong Yb-4f electron correlations on the electronic structure. PBE-GGA and TB-mBJ predict half-metallic behavior of TlYbSe2, where the spin-up channel shows semiconducting character and the spin-down channel shows metallic character. The DFT+U method properly captures the localization of Yb-4f electrons and reveals an indirect narrow band gap of approximately 0.62 eV, confirming semiconducting behavior. Volume optimization curves were computed using the BirchMurnaghan equation of state to accurately determine the equilibrium structural parameters and bulk modulus. Phonon dispersion curves and phonon density of states were calculated to verify lattice dynamical stability. Optical properties show small anisotropy, with static dielectric constants epsilon 1(0) ti 10.0 (x-axis) and 12.5 (z-axis), absorption peaks at ti 3.5 eV (x-axis) and ti 5.0 eV (z-axis) in the visible and ultraviolet regions, refractive indices eta(0) ti 3.20 (x-axis) and 3.5 (z-axis), and prominent plasmon resonances around 10 eV, while the absence of infrared intraband transitions further supports the semiconducting nature. Thermodynamic properties calculated using the quasi-harmonic Debye model show typical thermal expansion, lattice softening with temperature, Dulong-Petit type specific heat behavior approaching ti 100.0 J/mol & sdot;K, and a moderate Debye temperature theta D ti 181 K, indicating good thermal stability. Collectively, these results establish TlYbSe2 as a strongly correlated narrow-band-gap semiconductor with promising potential for applications in optoelectronic, spintronic, and thermally tunable devices.

Structural and magnetic properties of double perovskite,La2CoFeO6 synthesised by hydrothermal method have been studied in detail. It crystallises in rhombohedral crystal (S.G 161) structure. The well-formed grains show cubical morphology with average particle size of similar to 308 nm. XPS analysis reveals multiple oxidation states of Fe and Co ions. Systematic and detailed study of magnetic behaviour in light of XPS analysis shows that there are competing ferromagnetic (FM) and antiferromagnetic (AFM) interactions which leads to spin glass behaviour and Griffiths like phase above the Neel Temperature (similar to 322 K). Arrott plots reveal that there is no spontaneous magnetisation and weak ferromagnetic coupling present may be attributed to short range ferromagnetic ordering. The effective paramagnetic moment is estimated to be 4.41 mu(B)/f.u, and it indicates that not all the ions are in high spin state. The room temperature I-V characteristics show varistor like behaviour. Temperature dependent resistivity studies show that the conduction mechanism is governed by Mott-variable range hopping model. Overall, synthesised LCFO compound show promising magnetic, transport properties well correlated with its structure which could be further explored for spintronic applications.

In the current research work, we present a comprehensive study of the electronic and optical properties of heavy rare-earth–based thallium diselenides, TlRSe2 (R = Dy, Ho, Er). Spin-polarized electronic structure calculations were performed using the PBE-GGA and TB-mBJ exchange–correlation potentials.The spin-up band gaps were obtained as 2.04 eV and 2.46 eV using PBE-GGA, and 3.10 eV and 3.51 eV using TB-mBJ for TlDySe2 and TlErSe2, respectively, whereas the spin-down electronic states reveal zero band gaps for TlDySe2 and TlErSe2, confirming their half-metallic character. TlHoSe2 shows a finite bandgap for both the spins. For spin up, band gap value found to be 2.50 eV using PBE-GGGA and 2.30 using TB-mBJ, whereas for spin down, band gap value found to be 0.42 eV using PBE-GGGA and 0.65 using TB-mBJ. The observed behaviour represents the semicondunting nature of TlHoSe2. The optical properties, evaluated using the TB-mBJ potential, demonstrate good agreement with the Penn model. The calculated static dielectric constants were found to be 15.0, 6.5, and 11.0, and corresponding static refractive indices are 3.90, 2.54, and 3.40 for TlDySe2, TlHoSe2 and TlErSe2, respectively. The negligible absorption in the infrared region for TlDySe2 and TlErSe2 reflects their metallic response, whereas the absence of infrared absorption in TlHoSe2 verifies its semiconducting behavior. Moreover, the strong ultraviolet absorption indicates that TlRSe2 compounds have significant potential for UV absorber applications, including photovoltaics, photodetectors, and UV-shielding technologies.

The pressure-dependent physical properties of the half-Heusler alloy HfNiSn were investigated via first-principles calculations within the PBE-GGA framework. Structural optimization revealed that HfNiSn is most stable in a nonmagnetic γ-phase cubic structure (space group F 43m ). Electronic structure analysis revealed semiconducting behavior with an indirect band gap of 0.36 eV, whereas the formation and cohesive energy values confirmed its thermodynamic stability. The calculated elastic constants, Young’s moduli, shear moduli, and Poisson’s ratios demonstrate the mechanical stability and ductility characteristics for the studied pressure range. The optical spectra indicate strong absorption in the visible and ultraviolet regions, with the optical conductivity being maximized in the visible range and enhanced under pressure. These findings highlight the favourable electronic, mechanical, and optical properties of HfNiSn, supporting its potential in future optoelectronic applications.

Solar cells based on a dye as a sensitizer have compelling importance in the field of energy conversion. New developments in this rapidly expanding area are continuously appearing in literature based on dye as a sensitizer for the new type of solar cells with improved efficiency. Therefore, the current review is focused on a different aspect of solar cells and studies to evaluate their efficiencies in harvesting solar energy. The review summarizes stepwise advancements in the solar cell with a merocyanine as sensitizer from the point of origin to the current status. Various attempts to improve the efficiency of solar cells using merocyanine derivatives as sensitizers including the use of natural as well as synthetic dyes and their different substitutes have been discussed. Besides, review have also included the use of nanomaterials with merocyanine dyes to improve the efficiency of solar cells. So here, we have summarized all types of solar cell parameters and their role in energy conversion.

A spiropyran-oxazine coupled probe was synthesized via photochromic oxazine, which has the potential to act as a probe for metal ions due to the presence of additional donor atoms. The structure of the probe was analyzed spectroscopically. Analysis of the probe through techniques like naked-eye detection, UV-vis spectroscopy, smartphone-assisted digital colorimetry, and cyclic voltammetry revealed that the probe can be used for sensing and monitoring gadolinium ions. The probe displayed a visible change in color from faint yellow to intense yellow on adding gadolinium ions. Digital colorimetric, UV-vis, and cyclic voltammetric analysis provided 107 +/- 2 nM, 0.17 +/- 0.02 mu M, and 0.80 +/- 0.14 mu M, respectively, as the limit of detection value of the probe for gadolinium ions.

Rare-earth selenides have attracted significant attention as promising materials for applications in photovoltaics, renewable energy, telecommunications, and aerospace, owing to their low dimensionality and intrinsic semiconducting properties. In the present study, first-principles calculations were performed on thallium-based rare-earth selenides, Tl(Nd/Gd/Tb)Se2, to investigate their structural stability, optoelectronic, and thermodynamic properties. Structural analysis, based on volume optimization curves, confirmed that all Tl(Nd/Gd/Tb)Se2 compounds are stable in the α-NaFeO2-type crystal structure. To explore their electronic behavior, various exchange–correlation functionals such as LDA, PBEsol, WC, PBE-GGA, and TB-mBJ were employed. The density of states (DOS) profiles calculated using LDA, PBEsol, and WC indicate that TlNdSe2 exhibits half-metallic character, predominantly contributed by spin-up states. In contrast, the PBE-GGA and TB-mBJ functionals predict a semiconducting nature for TlNdSe2. For TlGdSe2, all exchange–correlation functionals consistently predict a semiconducting nature. In contrast, TlTbSe2 is predicted to be a semiconductor only by the TB-mBJ functional, while all other functionals indicate a half-metallic character, dominated by spin-down states. The TB-mBJ functional is widely regarded as more reliable for bandgap estimation, due to its better agreement with experimental data, it was employed to compute the electronic band structure and optical properties. These properties were found to be in good agreement, further validating the functional's suitability. Additionally, the investigation was extended to evaluate the thermodynamic properties of these compounds, which revealed favorable characteristics for potential thermodynamic applications. Overall, the combined analysis of electronic, optical, and thermodynamic properties demonstrates promising features of the Tl(Nd/Gd/Tb)Se2 compounds, indicating their potential for use in future optoelectronic and thermoelectric devices.

Pure WS2 and composite WS2/MoS2 thin films deposited by the CBD method have been studied for photodetector applications with different wavelengths. XRD results show a polycrystalline rhombohedral phase with crystallite size of 41 nm and 27 nm, for pure and composite thin films, respectively. The optical absorption spectra of pure WS2 and composite WS2/MoS2 thin films show absorption in the region from 320 nm to 720 nm, making these thin films a workable photodetector in the visible range. The band gap was observed to be 2.18 eV, 2.86 eV for WS2 while 1.97 eV, 2.83 eV, 3.32 eV for WS2/MoS2. I–V characteristics were measured across the heterojunction to determine the transport properties. Low saturation current of the order of 10−8 A, low sub-second response and recovery time for monochromatic light sources of red, green and blue were obtained. The linear dynamic range was 3.00–11.94 which makes these thin films, by comparing the figure of merit value the WS2/MoS2 nanocomposite heterostructure thin film over p-Si shows prominent results for application as broad-range photodetectors in the visible region.

This study presents a comprehensive investigation of the structural, optical, and magnetic properties of cobalt-doped nickel oxide (Ni1-xCoxO, 0.0 <= x <= 0.08) nanoparticles synthesized via a citrate-assisted sol-gel method. X-ray diffraction (XRD) combined with Rietveld refinement reveals a doping-induced phase evolution from a mixed-phase system (NiO and metallic Ni) to a single-phase cubic NiO structure at x = 0.08. Raman and FTIR analyses confirm the incorporation of Co into the NiO lattice, along with strain-induced structural distortions and lattice disorder. Magnetic measurements demonstrate a distinct transition from ferromagnetic (FM) behaviour at x = 0.04 to antiferromagnetic (AFM) ordering at x = 0.08, attributed to Co-mediated exchange interactions and strain-induced modulation of spin correlations. Optical absorption spectra show bandgap tuning in the range of 2.9-3.5 eV, driven by defect-induced states at low Co content and quantum confinement at higher doping levels. These results highlight the crucial role of Co doping in simultaneously tailoring the structural, magnetic, and optical properties of NiO nanoparticles, establishing their potential for multifunctional applications in spintronic, optoelectronic, and photovoltaic devices.

In this article, the effects of increasing the Fe concentration in La2Co2-xFexO6 (x = 1.10, 1.15, 1.20, 1.25, and 1.30) nanoparticles were systematically investigated. The Rietveld refinement analysis of La2Co2-xFexO6 compositions confirmed the orthorhombic structure. A clear increase in the lattice parameters and unit cell volume was observed, accompanied by enhanced distortion of the Fe-O2-Co bond angle with increasing Fe content. Room-temperature magnetic hysteresis indicates weak ferromagnetic behavior, with both coercivity and remanent magnetization increasing as the Fe content increases. The N & egrave;el temperature of La2CoFeO6 (similar to 270 K [1]) was tuned toward higher temperatures with small increments in the Fe concentration. For composition, x = 1.10, a magnetic transition near similar to 300 K was observed, along with a large exchange bias (EB) effect at 2 K under zero-field cooling conditions. The magnitude of the EB progressively decreases as Fe concentration increases toward the end-member LaFeO3, which is known to be an antiferromagnetic insulator. This reduction is due to decreasing competition between the antiferromagnetic and ferromagnetic interactions caused by increased homogeneity in the oxidation states of the Fe/Co B-site ions, as confirmed by X-ray photoelectron spectroscopy studies. The observed near-room-temperature magnetic transition and significant EB suggest the promising potential of these materials for spintronic applications.

Despite extensive research, structural and magnetic uncertainties of La2CrMnO6 double perovskites remain unresolved, requiring further investigation. This study examines the Fe substitution at the Cr site in La2Cr1-xFexMnO6 (x = 0.00, 0.50, 1.00) (LCFM), synthesized via the conventional solid-state reaction method. XRD and Rietveld refinement confirm the orthorhombic Pbnm phase in LCFM, with crystallite size and lattice parameters increasing with Fe substitution at the Cr site. FESEM analysis revealed a reduction in grain size while UV-Visible spectroscopy reveals a reduction in band gap. X-ray photoelectron spectroscopy (XPS) confirmed the presence of mixed oxidation states Cr3+/Cr6+, Fe2+/Fe3+, and Mn3+/Mn4+. Magnetic measurements of LCFM reveal increased Hc, decreased Mr, and preserved multi-domain structure upon Fe3+ substitution at the Cr3+ site, driven by superexchange and double exchange interactions. Reduced grain size, optical band gap, and magnetic properties in Fe-substituted La2CrMnO6 suggest its suitability for optoelectronic and spintronic applications.