​In this study, the electronic and optical properties of a two‑dimensional van der Waals ZnO/MoSe₂ heterostructure were investigated using first‑principles calculations within the framework of density functional theory (DFT). To obtain a more accurate description of the electronic structure, both the GGA‑PBE approximation and the hybrid exchange–correlation functional HSE06 were employed. The results reveal that the heterostructure exhibits an indirect band‑gap semiconducting nature, with a band‑gap value of 1.26 eV calculated using the HSE06 functional. The projected density of states analysis confirms a type‑II band alignment accompanied by an efficient spatial separation of electrons and holes across the two layers. Charge‑density difference analysis further indicates a net charge transfer from the ZnO layer to MoSe₂, resulting in the development of an internal interfacial electric field that can effectively suppress carrier recombination.Moreover, the influence of biaxial strain within the range of ±4% on the band structure and band‑edge positions was examined. The results show that compressive strain leads to an increase in the band gap, and at approximately −3% strain, an indirect‑to‑direct band‑gap transition occurs. Favorable band‑edge alignment with respect to the redox potentials of water is also preserved under −1% and −3% compressive strain. Optical property calculations reveal a high absorption coefficient in the visible and ultraviolet regions, reaching maxima on the order of 10⁶ cm⁻¹. These findings demonstrate that strain engineering can effectively tune the electronic and optical characteristics of the ZnO/MoSe₂ heterostructure, making it a promising candidate for photocatalytic applications, particularly in water‑splitting processes.

This work investigates the synthesis and properties of barium hexaferrite (BaFe12O19) and its Reduced Graphene Oxide (rGO) nanocomposites using the auto-combustion sol-gel method. BaFe12O19 is known to have certain limitations in practical applications, which motivates the development of BaFe₁₂O₁₉-based nanocomposites with carbon-based materials such as rGO to enhance their multifunctional behavior. The study explores the impact of different rGO content (10%, 20%, 40%, and 50% Wt.%) on the nanocomposites’ structural, optical, and magnetic properties. The techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and magnetic hysteresis measurements were used to characterize the samples. The structural studies revealed the formation of nanocomposite. Optical studies indicated that the band gap energy decreased from 1.62 eV for pure BaFe12O19 to 1.48 eV for the composite containing 50% rGO. Concurrently, magnetic hysteresis measurements showed a reduction in saturation magnetization, from 54.21 emu/g for pure BaFe12O19 to 23.38 emu/g for the 50% rGO composite.

In this study, the electronic and optical properties of the monolayer 2H-WSe₂ were investigated using density functional theory with the PBE and HSE06 exchange–correlation approximations. Initially, the lattice constants were optimized using the GGA-PBE approximation, yielding an equilibrium lattice constant of a=b=3.369 Å. Comparison of the band structures indicates that both approximations predict a direct band gap between the Γ and M points; however, the band gap calculated with the hybrid HSE06 functional is significantly larger than that obtained with PBE. This increase is attributed to self-interaction correction and the inclusion of a portion of Hartree-Fock exchange in the hybrid functional. Analysis of the density of states shows that the valence band is mainly composed of Se_4p orbitals, while the conduction band is dominated by W_5d orbitals.The optical properties of the compound were also calculated for both in-plane and out-of-plane directions in each approximation. The results indicate pronounced optical anisotropy, with higher values of the dielectric constants and refractive indices along the in-plane direction. Overall, comparison of the two approximations shows that the HSE06 hybrid function predicts different values of the band gap and optical response compared with PBE, providing a more accurate description of the electronic and optical behavior of monolayer 2H WSe₂.

Using Density Functional Theory (DFT) within the Quantum ESPRESSO package, this study meticulously explores the structural and optoelectronic characteristics of lead-free Cs2InAgCl6, Cs2InAgBr6, and Cs2InAgI6 double perovskites. Stability assessments, grounded in Goldschmidt's tolerance and octahedral factors, confirm that all three compounds adopt stable cubic structures. Electronic band structure calculations employing both the Generalized Gradient Approximation (GGA) and the Heyd-Scuseria-Ernzerhof (HSE06) hybrid exchange-correlation functional reveal direct band gaps of approximately 3.16, 1.49, and 0.09 eV for Cs2InAgCl6, Cs2InAgBr6, and Cs2InAgI6, respectively. Notably, Cs2InAgCl6 and Cs2InAgBr6 exhibit significant optical absorption (similar to 105 cm(-1)) in the visible spectral range, underscoring their potential in optoelectronic and optical applications.

The utilization of magnetoelectric composites, particularly core-shell configurations, enhances their versatile applications in various sectors such as medicine and data storage. Among these composites, the perovskite-spinel combination is distinguished by its significant potential. A series of (1-x) BiFeO3-(x) CoFe2O4 (where x = 0.0, 0.2, 0.5, and 1.0) nano core-shell structures were synthesized using a sol-gel auto-combustion method to explore their multifunctional capabilities. Structural analyses identified peaks corresponding to both perovskite and spinel phases. Field Emission Scanning Electron Microscopy revealed a reduction in average particle size with an increase in CoFe2O4 content.The particle size in the BFO80-CFO20 sample has been reduced from 243 nm to 34 nm. Additionally, Transmission Electron Microscopy images of the BFO80-CFO20 sample highlighted the evolution of core-shell structures. Our findings indicate that higher CFO concentrations significantly affect the dielectric, ferroelectric, and optical properties. The bandgaps of the nanocomposites BFO80-CFO20 and BFO50CFO50 were estimated to be 1.43 eV and 1.39 eV, respectively. Magnetic analysis showed increases in both saturation magnetization and remanent magnetization with increased CFO content, while the coercive field followed a different trend. The saturation magnetization values for the samples BFO, BFO80-CFO20, BFO50CFO50, and CFO were calculated as 0.205, 14.612, 28.374, and 74.105 emu , respectively. The measured values for the same samples were 0.08, 5.07, 11.34, and 34.01 emu , respectively. Further, the electrochemical properties were thoroughly investigated using cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy.

In this study, the sol-gel synthesis technique was harnessed to craft nanocomposites of (1-x)La0.7Sr0.3MnO3-(x)BTO with x values of 0.4, 0.6, and 0.8. The attributes of these meticulously engineered materials were exhaustively explored using a diverse suite of characterization methods. X-ray diffraction analysis irrefutably confirmed the phase purity of the perovskite structure, emphasizing the synthesis's precision. Furthermore, Diffuse Reflectance Spectroscopy shed light on the optical properties of the nanocomposites, revealing a significant shift in bandgap energy that correlated directly with the BTO concentration. Specifically, an increment in BTO concentration resulted in a systematic expansion of the bandgap from 1.51 eV to 1.44 eV. For an in-depth analysis of the magnetic characteristics of the composites, Vibrating Sample Magnetometry was utilized. The magnetic analysis identified a conspicuous reduction in saturation magnetization, highlighting the complex interplay between the composite components at the nanoscale. Additionally, the dielectric properties were rigorously investigated through dielectric measurements, which unveiled a notable increase in the dielectric constant, accompanied by the emergence of novel relaxation behaviors. This finding indicates that adjusting the BTO content within the nanocomposites not only modifies their dielectric properties but also provides a method for fine-tuning their functional performance.

In this study, carbon with graphene oxide (GO)-like composition (C GO ) was prepared from oak fruit peel (OFP) using a room-temperature method.

In this research, BaFe12O19/GO (GO:10, 20, 40, and 50 wt%) nanocomposites were synthesized by sol-gel auto combustion method and their structural, optical, magnetic and dielectric properties were investigated. The x-ray diffraction results for all nanocomposites validate the formation of a hexagonal phase of Ba hexaferrite. The crystallite size decreased with incorporation of graphene oxide (GO) in the hexaferrite phase and making the nanocomposites. In the FESEM analysis, a change in the surface morphology was observed with an increase in the percentage of GO for samples BFO-40GO and BFO-50GO. The band gap energy of the nanocomposites decreased with increasing the amount of the graphene oxide. Measurements of the magnetic hysteresis loop for all nanocomposites were conducted using a vibrating sample magnetometer at room temperature. By increasing the percentage of GO, a decrease in the saturation magnetization was observed for the samples. A decrease in dielectric constant and loss function were also detected at low frequencies when the GO continent goes up. The nanocomposite sample of BFO-40GO exhibited the highest observed value for real part of the Modulus.

Sol-gel synthesized La(1-x)SrxMnO3-BaTiO3 nanocomposites with varying strontium content were investigated to explore the influence of Sr doping on their properties. X-ray diffraction confirmed the perovskite phase purity. Sr doping resulted in a tunable bandgap, widening from 2.33 eV to 2.57 eV as Sr content increased, as revealed by Diffuse Reflectance Spectroscopy. Vibrating Sample Magnetometry measurements exhibited a Sr-dependent decrease in saturation magnetization (22 emu/g for x = 0.2 to 14 emu/g for x = 0.5). Dielectric analysis demonstrated an enhanced dielectric constant and the emergence of new relaxation behaviors with Sr doping. These findings unveil the tailorable optical, magnetic, and dielectric properties of LSMO-BTO nanocomposites due to Sr doping, suggesting their potential for diverse technological applications.

The structural, optical, and magnetic characteristics of the (CoFe2O4) (x) - (BaTiO3)(100-x) (x = 10, 20, 30, 40, 50) nanocomposites prepared using the sol-gel technique were examined. X-ray diffraction data confirm formation of the tetragonal phase for BTO and the spinel phase for CFO for all composites. The magnetic hysteresis loop measurements were performed using a vibrating sample magnetometer at room temperature. All of the composites had improved ferromagnetic characteristics, which are highly influenced by the amount of the CFO phase. The bandgap energy values decreased as the CFO concentration increased. The dielectric constant, loss function and conductivity for samples were measured.

In this work, the samples of MgFe2O4 (MFO)x–BaTiO3 (BTO) (100-x) (x = 10, 20, 30, 40, 50) are synthesized by a sol–gel process. According to the X-ray diffraction data, all composites have the tetragonal phase for BTO, and the spinel phase for MFO. In accordance with FESEM, the ferrite particles become more agglomerated, and have an irregular shape as the MgFe2O4 concentration increases. The hysteresis loops (M–H) measured at room temperature indicates an increase in the saturation magnetization with an increase in the MFO content. The band gap dependency on the MFO content is also studied using the UV–visible spectra, which show that the band gap energies are in the range of 2.17–2.70 eV. With an increase in MFO, the dielectric constant decreases, and the dielectric tangent loss increases. Also according to the Nyquist plots, as the MFO phase increases in the composites, the diameter of the semicircle also increase indicating the higher resistivity.

In this research, ZnO/ ZnFe2O4 nanocomposites with a weight ratio (1:1) were made using hydrothermal method and annealing temperatures of 600°C and 700°C. Structural, optical, and magnetic properties of the synthesized powders were characterized using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), ultraviolet-visible spectrometer, and vibrating sample magnetometer (VSM). The results obtained from the XRD diffraction patterns confirmed the formation of the mixed phases, hexagonal zinc oxide and cubic spinel phases of pure zinc ferrite. FESEM images showed that with the increase of annealing temperature, the samples have a cohesive and agglomerated structure. The measurement of the absorption spectra of the synthesized samples showed that the absorption in the visible region increases with increase in annealing temperature. The optical band gap value for the ZnO/ZnFe2O4 composites were in the range of 2.1-2.2 eV which is between the band gap values of ZnO (3.37 eV) and zinc ferrite (1.8 eV). The hysteresis loops measured with VSM indicated a soft and weak ferromagnetic magnetic behavior for both samples.

Halide double perovskites have recently received much attention due to their application in optoelectronic devices. Cs2InAgCl6 is an exciting compound with a cubic unit cell, Fm-3m space group, and a direct band gap of about 3 eV. This research studied the effect of Br ion doping instead of Cl with the combination of Cs2InAgCl(6x)Brx (x values between 0 and 3) using density functional theory (DFT) calculations with GGA approximation and norm-conserving pseudopotentials of PBE type. We found that with an increase in Br concentration, the investigated compounds retain their cubic phase. The compounds' calculated lattice constants and band gaps were about 10.44-10.71 & ANGS; and 2.12-0.62 eV, respectively. The accurate band gap values were obtained between 3.16 and 1.68 by HSE06 hybrid functional as exchange-correlation. The calculations of the band structure and density of states indicate the direct electron transition from the valence band to the conduction band at the gamma point of the Brillouin zone of the studied compounds. The studied compounds' optical properties show high absorption in the visible and ultraviolet regions, appropriate optical conductivity, and refractive index.

In this work, the samples of MgFe 2 O 4 (MFO) x –BaTiO 3 (BTO) (100-x) (x = 10, 20, 30, 40, 50) are synthesized by a sol–gel process. According to the X-ray diffraction data, all composites have the tetragonal phase for BTO, and the spinel phase for MFO. In accordance with FESEM, the ferrite particles become more agglomerated, and have an irregular shape as the MgFe 2 O 4 concentration increases. The hysteresis loops (M–H) measured at room temperature indicates an increase in the saturation magnetization with an increase in the MFO content. The band gap dependency on the MFO content is also studied using the UV–visible spectra, which show that the band gap energies are in the range of 2.17–2.70 eV. With an increase in MFO, the dielectric constant decreases, and the dielectric tangent loss increases. Also according to the Nyquist plots, as the MFO phase increases in the composites, the diameter of the semicircle also increase indicating the higher resistivity. Graphical Abstract

In the present study, magnetic nanomaterials (Mg1−xCaxFe2O4, 0.0 ≤ x ≤ 0.8) were prepared via a simple sol-gel method. The samples were characterized using XRD, TEM, SEM, EDX, FTIR, BET, and VSM. The structural and magnetic properties of prepared nanomaterials (NMs) were investigated, and the adsorption capacity of Cd2+ from aqueous solution was evaluated via flame atomic absorption spectroscopy (AAS). The impact of several factors on Cd2+ adsorption such as contact time (1–60 min), pH (3–8), dose (0.003–0.03 g), and initial concentration of Cd2+ (5–60 mg L−1) has been assessed. The adsorption capacity of Cd2+ for the prepared NMs followed the pseudo-second order. Several isotherm models were analyzed, and the Langmuir model was found to be the best fit for NMs. Among as-prepared NMs, Mg0.8Ca0.2Fe2O4 (MCF2, cubic 97

In this work we implied density-functional theory (DFT) to study structural and optoelectronic properties of the double perovskite Cs2InSbCl6 (CISC), Cs2InBiCl6 (CIBC) and Cs2InAgCl6 (CIAC) compounds. We found that structural parameters such as lattice constant and bulk modules are in close agreement with other computational and experimental results. Bandstructure calculations with norm-conserving pseudopotentials show that these compounds are semiconductors with a direct band gap that stay at the Gamma point of the first Brillouin zone. Their band gap values vary from 1.47 to- 3.16 eV. The valence band maximum (VBM) is primarily composed of the Cl-p, In-s, Sb/Bi-s, and Ag-s states, and the conduction band minimum (CBM) is composed of the Cl-s/p, In/ Sb/Bi-p orbitals. Optical studies include dielectric function, absorption, optical conductivity, reflectivity, and refractive and extinction indexes were performed in the photon energy range 0.0 up to 14.0 eV to investigate the optical response of these structures. These compounds have large optical absorption of incident radiation in the range of about 2-14 eV. Therefore, they can potentially be promising candidates for use in optoelectronic devices.

In this study, the effect of Mn substitution on the structural, magnetic, electronic and optical properties of GaFeO3 (GFO) were investigated with density functional theory (DFT). A detailed discussion on the magnetic exchange interaction was performed and new aspects like antiferromagnetic coupling strength and exchange coupling parameter were studied. GFO has an antiferromagnetic structure and spontaneous electric polarization in the ground state. The antiferromagnetic structure arises from the magnetic exchange interaction between Fe1 and Fe2 atoms via O atoms. Replacing the Fe1 atom with the Mn atom changes the magnetic exchange interaction in GFO and as a result alters the ground state properties of GFO. Structural investigations indicate that the lattice parameters and unit cell volume are increased with Mn substitution. Also, increasing the Mn concentration leads to an increment in the total spin magnetic moment because of the different magnetic moments of Fe and Mn atoms. This increase is accompanied by an antiferromagnetic to ferrimagnetic (AFM-FIM) transition. Furthermore, the antiferromagnetic coupling strength is decreased with the Mn substitution. Also, electronic investigations reveal the formation of new states around the Fermi surface in spin up channel after the substitution of Mn in the GFO host structure. These new states make possible optical transitions at energies less than the GFO band gap. The number of these new states is increased with increasing the Mn concentration. The imaginary component of the dielectric function, absorption coefficient, and real component of optical conductivity are increased with an increase in the Mn concentration in the energy range up to about 3 eV.

The non-doped and alkali (Na,K)-doped Cu2ZnSnS4 (CZTS) thin films were prepared using the sol–gel spin-coating method on the glass substrate, and the changes in the structural, optical, and electrical characteristics of the films were examined and compared. The structural study results obtained showed that all the prepared samples had a kesterite structure. The scanning electron microscopy and Raman analysis showed that the samples' surface and crystalline quality were significantly changed by doping, and an appropriate amount of dopants can improve them. The optical study showed that the energy gap values for the CZTS layers were in the range of 1.40–1.61 eV, which is desirable for solar cells. Moreover, good optical conductivity values (1012–1015 s–1) and high absorption coefficients (up to 1.8 × 105 cm–1 in the visible region) were obtained for the CZTS thin films. Investigation of the sample’s electrical properties indicated that non-doped and doped CZTS was p-type, and therefore doping did not change the type of the charter of thin films. Moreover, the carrier concentration of the samples significantly increased up to 8.00 × 1019 cm–3 (one order of magnitude increase) with the doping. The samples’ photovoltaic properties showed that the fabricated ZnS|CZTS hetero-junction exhibited good rectifying behavior and the doped layers had better diode parameters. Overall, the results showed that the CZTS thin films doped with an appropriate amount of dopants (1% Na and 1.5% K) had better structural, optical, and electrical properties. The photo-electrical study of the samples showed that for all samples, photocurrent under illumination significantly increased (especially for Na-doped CZTS thin films), indicating that the CZTS thin films are suitable for solar energy conversion.