Indirect Energy Band Gap Research Articles

Silver doping effect on the electrochromic performance of the WO3 thin films produced by thermal evaporation in vacuum

Ag doped WO3 thin films are successfully fabricated by thermal evaporation method in vacuum as precursor, and then annealed at 450 °C in nitrogen gases atmosphere. Cyclic voltammetry, repeating chronoamperometry, chronocolumetry and optical transmittance are recorded in 1 M LiClO4/propylene carbonate electrolyte. The color of the WO3 thin films changes from transparent to the blue under the applied potential of -1.8 and +1.9 V. XRD studies show that all the films have a polycrystalline structure of WO3. The molecular formation is also confirmed by Raman and X-Ray photoelectron spectroscopy (XPS). The EDS elemental mappings clearly confirm the homogeneous distribution of Ag, W and O elements into the WO3 network. From the optical studies, indirect band gap energy of the WO3 decreases as Ag doping level increases. The best coloration and bleaching times (2.33 and 1.25 s) are obtained for the Ag(2%):WO3 thin films, compared to the pure WO3 (3.79 and 1.96 s). The produced WO3 films exhibit high reversibility (39.6/69.1%), high coloration efficiency values (26.3/141.2 cm2/C), and good cycling stability. From the EIS measurements, the charge-transfer resistance is Ag(2%):WO3 < the pure WO3 < Ag(5%):WO3 < Ag(8%):WO3, which means that Ag(2%):WO3 has the biggest electrochemically active surface area. Electronic energy levels of the pure WO3 and the Ag:WO3 thin films are also given. From the Mott-Schottky studies, it is determined that the donor concentration of the materials is of the order of 1014-1015 cm−3. In the literature, there are very limited studies related to electrochromic thin films by thermal evaporation in vacuum. In this sense, the reported results in this study are promising for the electrochromic applications.

Structural evolution and magnetic, optical, and optoelectronic properties changes in annealed Co0.5Sr0.5Fe2O4 nanoparticles: A comprehensive study

A sample of Co0.5Sr0.5Fe2O4 nanoparticles was synthesized by the coprecipitation technique to explore the effect of annealing on the structure and some physical properties of the produced material. The coprecipitated sample consists of an orthorhombic strontium carbonate phase and the required cubic Co0.5Sr0.5Fe2O4. Annealing at elevated temperatures (900 °C) leads to the formation of cubic and hexagonal phases. This crystal structure was confirmed by X-ray diffraction analysis (XRD). The accuracy of the cation distribution of the cubic phase determined from the Rietveld analysis of XRD patterns is demonstrated by matching the experimental and theoretical lattice constants. There are several noticeable changes in aspects as the annealing temperature goes up. The transmission electron microscopy (TEM) images indicated that heating substantially affects the growth and densification of the smaller nanoparticles. There is a drop in the longitudinal and transverse wave velocities, bulk, rigidity, Young's moduli, Poisson ratio (σ), and Debye temperature (θD) with annealing and grain growth. The saturation magnetization and coercive field are enhanced with annealing. The particle size distribution calculated from TEM is confirmed and supported by the switching field distribution. The indirect optical bandgap energy (Eg) decreased with annealing. The present study concentrated on the thermal treatment impacts on various optical parameters, such as the refractive index and extinction coefficient. The optoelectrical parameters, such as the dielectric constant, dielectric loss, and optical and electrical conductivity, were extensively investigated, giving valuable insights, and their results were interpreted. These findings suggest potential applications in magnetic storage, sensors, and optoelectronics fields.

DFT Analysis of Transition Metal (TM) Substitutions on Cu‐Based Chalcogenides: Structural, Electronic, and Thermophysical Properties for Interface Thermal Performance and Energy

ABSTRACTThe current investigation employs first‐principles DFT (density functional theory) calculations to examine the influence of transition metal replacements on the structural, thermodynamic, and thermoelectric properties of Cu‐based chalcogenides TMCu3Se4 (TM = Nb/Ta/V). The PBE‐generalized gradient approximation (GGA) model is utilized to compute the fundamental properties of Cu‐based chalcogenides under study. A thorough examination of the energy band structures indicates that these chalcogenides are semiconductor compounds with indirect energy bandgaps. We can infer from the calculated energy band structures that the bandgap values are 1.67, 1.77, and 1.05 eV for NbCu3Se4, TaCu3Se4, and VCu3Se4, respectively. The values for NbCu3Se4, TaCu3Se4, and VCu3Se4 are 0.661, 0.998, and 0.996, respectively. These values make them highly appropriate for usage in thermoelectric (TE) devices. The thermoelectric characteristics of pyrochlore oxides TMCu3Se4 (TM = Nb/Ta/V) suggest that these materials have promising potential for energy‐related applications. The analyzed thermodynamic properties demonstrate that the Cu0based chalcogenide materials TMCu3Se4 (TM = Nb/Ta/V) exhibit a notable level of thermal stability.

Effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of zinc-boro-vanadate glasses

Abstract The effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of newly prepared zinc borovanadate glasses has been investigated. Density is found increased and molar volume decreased with Sm2O3 content. The glass transition temperature ( T g ) , crystallization temperature ( T c ) and the peak crystallization temperature ( T P ) increased with increase of rare earth oxide content. These findings demonstrated an excellent glass-forming ability and thermal stability of the glasses. The optical properties have been explored through UV–vis spectroscopy. The indirect optical band gap energy ( E opt ) decreased from 2.978 to 2.679 eV, Urbach energy ( ∆ E ) increased from 0.273 to 0.299 eV and refractive index increased from 2.403 to 2.489 with increase in Sm2O3. Elastic moduli, Poisson’s ratio, Hardness and fractal bond connectivity were computed theoretically as per Makishima Mackenzie model. It is found that these glasses have appreciable mechanical strength and rigidity. Phy-X/PSD software has been used to determine different radiation shielding characteristics for the energy range 0.015–15 MeV. The mass and linear attenuation coefficients are found higher, and half value layer, tenth value layer and mean free paths are found lower than many radiation shielding glasses quoted in the literature values. The obtained Z eq values varied from 15.828–29.118 for energy range from 0.015 to 15 MeV, which are greater than those reported for several commercial glasses, concretes and rocks. Due to the Compton scattering process, exposure build up and energy absorption factor are found to be highest in the medium energy region. The fast neutron removal cross-sections of the glasses are observed to be significantly high. For the first time, thermally stable and mechanically strong zinc borovanadate glasses mixed with Sm2O3 have been thoroughly investigated for various properties and concluded that these glasses are suitable for optoelectronics and γ-shielding applications.

Judd-Ofelt analysis and temperature sensing properties of polyethylmethacrylate (PEMA) networks doped with CdNb2O6: Er3+/Yb3+ phosphors

Research on the sensitivity of temperature measurements and optical thermometry involving rare earth ions has been an area of interest in the field of photonics and materials science. Introducing polymer networks as a new host material has an important role due to their properties including a versatile and stable environment for rare earth ions and rapid response in temperature detection. In this work, linear and crosslinked polyethylmethacrylate (PEMA) networks doped with Er3+/Yb3+ (1.5 mol % Er3+, 2 mol% Yb3+) synthesized by free-radical crosslinking polymerization with 0.1 EMA (weight %) at 60 °C were used to investigate direct and indirect optical bandgap energies and Urbach energy from UV–Visible spectra. The Judd-Ofelt (JO) approach was employed to analyze parameters Ωt (t = 2,4,6), spontaneous transition probabilities (Α), branching ratios (β) and radiative lifetimes (τ) as a function of linear and crosslinked PEMA doped nano-crystalline CdNb2O6: Er3+/Yb3+. The stimulated emission cross-sections of the transitions 2H11/2⟶4I15/2, 2S3/2⟶4I15/2 and 2F9/2⟶4I15/2 of Er3+/Yb3+ were calculated by two different methods; Fuchtbauer-Ladenburg formula and modified theory, respectively. The gain bandwidth cross-section product for the 2H11/2⟶4I15/2 was found to be 162.06. 10−28cm3, 260.94. 10−28cm3 and 461.20. 10−28cm3 of Er3+/Yb3+ embedded in linear, low and high crosslinked PEMA samples, respectively. JO parameters and stimulated emission cross-sections increased; therefore, radiative lifetimes decreased by increasing crosslinking content. In addition, the temperature dependence of upconversion (UC) luminescence was monitored under 975 nm excitation. The fluorescence intensity ratio (FIR) method examined the temperature sensing under two thermally coupled levels at 525 and 548 nm. The maximum sensitivities obtained from the FIR technique within the 300–650 K temperature range shifted to lower temperatures with increasing crosslinker content. Hence, linear and crosslinked polymer hosts doped rare-earth ions can be candidates for remote temperature sensors across various fields.

Radiative recombination model for BiSeI microcrystals: unveiling deep defects through photoluminescence

Abstract Pnictogen chalcohalides are semiconductors that have emerged as promising materials for energy conversion due to their exceptional optoelectronic properties. Their electronic configuration (ns2), particularly for Bi- and Sb-based compounds, can be a key factor in efficient carrier transport and defect tolerance, similarly, to Pb-perovskites. In the present study, the Bi-containing chalcohalide, bismuth selenoiodide (BiSeI) was synthesized via isothermal heat treatment of binary precursors in evacuated quartz ampoules. The synthesized BiSeI microcrystals exhibited a characteristic needle-like morphology and a near-stoichiometric composition. Both indirect and direct band gap energies of BiSeI were determined by ultraviolet–visible–near-infrared diffuse reflectance spectroscopy, with room temperature values of 1.17 eV and 1.29 eV, respectively. This study presents the first experimental investigation of the photoluminescence properties of BiSeI microcrystals resulting in a recombination model involving multiple defect states. This work provides valuable insights into the defect structure and recombination mechanisms within BiSeI, paving the way for further exploration of its potential in optoelectronic devices.

Sol-Gel Spin Coating Synthesis and Characterization of Cadmium Zinc Phosphate Thin Films: Structural, Optical, and Electrical Properties

This study successfully implemented the sol-gel and spin coating technique to grow cadmium zinc phosphate cadmium zinc phosphate (CZP) thin films on a glass substrate and p-Si wafer. Structural and morphological analyses were conducted via X-ray diffraction (XRD) and field-emission scanning electron microscopy (SEM). Additionally, the films’ linear and nonlinear optical properties, encompassing absorbance performance, energy gap, refractive index, dielectric, conductivity, and electronegativity, were systematically studied through UV–vis spectroscopy. XRD analysis uncovers the zinc ions substitution by cadmium ions in zinc phosphate’s unit cell, generating oxygen vacancies crucial for maintaining charge neutrality. SEM images then showcase the intricate and organized nano CZP framework. Shifting to optical studies, CZP film analysis spanning 190–2500 nm reveals an indirect energy band gap of 2.92 eV. Transitioning to electrical characteristics, the CZP/p-Si junction undergoes dark mode I-V-T analysis, elucidating the ideality factor, series resistance, and barrier height.

Evaluation of Band Structure of Single Crystalline Si-Rich SiSn thin Film

We evaluated the bandgap energy and optical properties of single-crystalline silicon-tin (Si1-x Sn x ) thin films utilizing Photoluminescence (PL), spectroscopic ellipsometry (SE), and X-ray photoelectron spectroscopy (XPS). The PL and SE results showed that the indirect and direct bandgap energy decrease with increasing Sn fraction. Furthermore, the change in the direct bandgap energy is larger than the indirect bandgap energy. This shows that Si1-x Sn x approaches the direct transition type. Then, the Sn fraction from the indirect-to-direct bandgap is estimated to be 47.2%. In addition, XPS results showed that the difference in valence band maximum between Si1-x Sn x and pure Si increased depending on Sn fraction. This is responsible for the decrease in the indirect and direct bandgap energy.

Crystal Structure, Optical, Photoluminescence, Raman, and Magnetic properties for Sm-doped Cr-Mg-Bi Ferrites using sensor

The current work,A series of rare earth Sm3+ ion substituted Cr-Mg-Bi ferrites Cr0.7Mg0.2Bi0.1SmxFe2-xO4 (x = 0.00, 0.02, 0.04, and 0.06) have beensynthesized by thesol-gel auto-combustion method. The XRD, FESEM, HRTEM,UV-Vis, FTIR, Raman spectroscopy, Photo Luminesce and Magnetic Properties analysis have been used to investigate structural, morphological, optical, Raman spectroscopy, Photo Luminesce and Magnetic Properties. Every sample contains a single-phase spinel structure, as confirmed by XRD.The substitution of Sm3+ ions is found to increase the lattice parameter from 8.258–8.248Å.A monotone diffraction peak (311) is visible near small angles of degrees (35.33 to 35.13). The Debye-Scherrer equation, the nanoparticles' crystallite size ranges from 35.357–54.778 nm.FE-SEMs reveal a spherical grain that groups and has a porous form, with particles 38.13 to 53.28 nmin size.HR-TEM micrographs illustrate spherical morphology and their average particle size decreases from 55.32 to 65.42 nm. The selected area electron diffraction (SAED) pattern confirms the crystal planes which were revealed from XRD calculations.The spinel structure was confirmed by FTIR spectroscopy, which found 414 cm-1 and 516 cm-1 vibrational band at the octahedral and tetrahedral sites.As the concentration of Sm3+ rises, the direct and indirect band gap energy values determined from UV-Vis show an increase and decrease.The generated NPs' semiconducting nature is confirmed by the strong correlation between the g-value and particle size change.Photoluminescence (PL) investigation shows that all processed samples have four bands.(i) peak centered at 412 nm, which is near-band edge emission and corresponds to the ultraviolet (UV) band,(ii) The violet band has a high-intensity peak at 434 nm,(iii) The blue band is related to a low-intensity, sharp peak located at 466 nm, and (iv) A broad peak at 502 nm with a very low intensity distinguishes the green band.The Raman spectroscopy investigation revealed that the CMBSF nanoparticles had a mixed spinel structure. The magnetic investigation shows that when the Sm content of ferrites increases, saturation magnetization drops from 39.86 to 33.16 emu/g.The sample's coercivity (Hc) increases from 16.06 to 21.90 KOe with Sm substitution.

Optical and gamma-ray shielding properties of calcium sodium borate glasses with varied equal concentrations of ZnO and BaO

This study presents the optical and radiation shielding characteristics of a newly developed borate glass, doped with equal quantities of ZnO and BaO, and modified with calcium and sodium. The glass samples were prepared using the melt quenching technique, with the composition formula (80-x-y)B2O3-10CaO-10Na2O-xZnO-yBaO, where x and y were varied at 5, 10, 15, and 20 mol%. Comprehensive analyses of the optical and gamma shielding properties were carried out using UV–visible spectrophotometry and Phy-X software, respectively. The UV–visible spectroscopic data allowed for the calculation of various parameters including the direct and indirect optical energy band gaps, refractive index, dielectric constants, and polarizability. It was observed that the direct optical energy band gap decreased from 3.91 to 3.10 eV, while the indirect band gap fell from 3.41 to 2.91 eV with increasing ZnO and BaO content. Conversely, the refractive index rose from 2.29 to 2.42 with higher concentrations of ZnO and BaO. The linear attenuation coefficients (LACs) across the range of 0.015–15 MeV exhibited an inverse relationship. Among the glass samples, B40Zn20Ba20 exhibited the lowest tenth value layer (TVL) and the highest effective atomic number (Zeff), indicating its superior performance as a radiation shielding material. Overall, the produced glass samples demonstrate commendable properties for both optical applications and radiation shielding.

Synthesis of MnO@Fe2O3 core-shell doped PVA/PVP polymeric nanocomposites for electronic and optoelectronic devices: Mechanical, electrical, and optical properties

Abstract The aqueous solution cast method was utilized to create biodegradable nanocomposite of polymers (PNC) films from a poly (vinyl alcohol) / poly (vinyl pyrrolidone) blend (70/30 wt%) and MnO@Fe2O3 nFs. The dislocation density, particle size, and interplanar distance were all calculated. The PNC films' surface shape changes from smooth to porous and somewhat rough because of the nanosized MnO@Fe2O3 particles' dispersion in the blend matrix, which diminishes the blended crystallites' size. The composite film's tensile strength increased from 9.45 MPa for the pure (PVA-PVP) film to 22.35 MPa due to the addition of 6 wt% MnO@ Fe2O3. The optical band gap decreases from 5.26 and 4.84 eV for pure (PVA/PVP) blend direct and indirect energy band gap to 5.18 and 4.71 eV for comparable values of 6wt% MnO@Fe2O3 nFs. Up to 6 wt% MnO@Fe2O3 concentration, PNC films' dielectric permittivity first declines, but it is substantially identical to the pure polymer blend matrix. The PNC sheet's dielectric permittivity increases nonlinearly with temperature, although its DC conductivity follows the Arrhenius law. Laser power was attenuated by (PVA- PVP)/MnO@Fe2O3 for both He-Ne and solid-state green laser beams. When the MnO@Fe2O3 concentration in the blend matrix rises to 6 wt%, the output power for lasers with 532 nm and 650 nm wavelengths drops from 5.49 to 2.4 mW and 19.8 to 9.4 mW, respectively. The findings suggest that nanocomposites exist and are widely recommended for optoelectronics, microelectronics, radiation detection, and several other uses.&amp;#xD;

On the response of the CR-39 NTD to low doses of gamma rays using optical and photoluminescence spectroscopy

In this work, the response of the CR-39 nuclear track detector (NTD) exposed to different low doses of gamma rays was investigated using UV–Vis and photoluminescence spectroscopy. Five NTDs of CR-39 were irradiated with low gamma-ray doses ranging from 10 to 120 kGy using a60Co source. The dose of gamma rays correlates with red shift in the absorption spectra of a gamma-irradiated CR-39 detector. As the gamma dose increases, the indirect and direct energy band gaps, as well as Urbach energy, decrease gradually. However, the decrease in the indirect optical band gap is greater than the decrease in the direct band gap. The observed spectra of the CR-39 detector after being irradiated with different doses of γ-rays showed an acceptable variation in photoluminescence (PL) emission spectra generated by a well-defined excitation wavelength of 290 nm. Starting at 45 kGy dose, the integrated area of the photoluminescence peak increases and tends to saturate, whereas the photoluminescence peak height is linearly correlated with the gamma dose with high sensitivity, which is 53.1 ± 6.3 CPS. kGy−1. According to the current findings, photoluminescence (PL) spectroscopy has a greater sensitivity than UV–Vis spectroscopy for measuring the response of the CR-39 detector to gamma rays in the dose range of 10–120 kGy. The results reflected a potential possibility of using the CR-39 detector in dosimetric applications of low gamma ray doses through the high resolution achieved by photoluminescence (PL) and UV–Vis spectroscopy.

Optical, AC conductivity and antibacterial activity enhancement of chitosan-silver nanocomposites for optoelectronic and biomedical applications

This study is aimed to prepare and investigate the optical, electrical and antibacterial activity of the environmentally friendly (green) chitosan (Cs)/silver nanocomposites. TEM demonstrated that AgNPs have a spherical shape with particle size ranged from 3 nm to 25 nm. UV analysis spectra of Cs and Cs/Ag nanocomposites showed that, increasing the content of AgNPs led to a noticeable increase in the values of Urbach energy (E U ) and a dramatic decrease in both the indirect (E ig ) and direct (E dg ) optical bandgap energies. It is found that (E ig ) and (E dg ) are decreased from (4.72/5.31 eV) to (2.47/4.19 eV). The formation of the AgNPs is verified by the existence of surface plasmon resonance (SPR) peak at ∼ (421–450) nm. Wemple-DiDomenico and Sellmeier oscillator models are employed and displayed a clear enrichment in the dispersion energy (E d ) and oscillator energy (E 0) as well as the linear and nonlinear optical parameters of Cs. It is observed that the linear (χ(1)) and nonlinear (χ(3) and n2) parameters are enhanced from 0.083, 0.868 × 10−14 and 1.584 × 10−12 to 0.153, 9.762 × 10−14 and 4.088 × 10−12. The novel results in our study nominate Cs/Ag nanocomposites for applications in linear/nonlinear optical devices. AC conductivity behavior of Cs and Cs/Ag nanocomposites is analyzed based on Jonscher’s law and the analysis showed that the overlapping large polaron tunneling (OLPT) is the dominant conduction mechanism for our samples. It is clear that the values of dielectric constant (ε′) of Cs and Cs/Ag nanocomposites are higher confirming the presence of interface polarization (IP) relaxation. Moreover, it is found that the antibacterial activity of Cs against Gram-negative (P. aeruginosa) and Gram-positive (B. thuringiensis) bacteria is found to be enhanced with increasing the content of Ag NPs. These results suggested that Cs/Ag nanocomposites will be good source for preparing bio-nanocomposites for use in many biomedical and industrial applications.

Synthesis, nonlinear optical activity, solvents effect, β-cyclodextrin effect, and cytotoxic activity on skin fibroblast and breast cancer cell lines of a new chalcone derivative of nabumetone

The use of small organic molecules, such as chalcones, for efficient applications as organic luminescent materials has attracted increasing attention owing to their interesting optical, photophysical, and biological properties. In this study, a new chalcone, 1-(4-isopropylphenyl)-5-(6-methoxynaphthalen-2-yl)pent-1-en-3-one (INM), was synthesized via base condensation between nabumetone and cuminaldehyde. INM was subsequently identified and characterized by FT-IR, NMR spectroscopy (1H and 13C), mass spectrometry, elemental analysis, X-ray diffraction, thermogravimetric analysis, and FESEM studies. Investigation of the solvent effect revealed that the π → π* transition involved a bathochromic shift from hexane to water and a large Stokes-shifted, twisted intramolecular charge-transfer emission in water. Diffuse reflectance spectral studies confirmed the formation of transparent INM chalcones with excellent crystallinity, and photoluminescence studies substantiated the low recombination rate of electrons and holes. Tauc plot analysis with the Kubelka–Munk algorithm revealed higher direct (3.57 eV) and indirect (3.41 eV) bandgap energies of INM. Density functional theory calculations at B3LYP/6-31G(d,p) revealed that INM had promising nonlinear optical activity (β ≈ 30.504 × 10−30 compared to a reference material, urea. Cell biocompatibility was evaluated after culturing skin fibroblasts and breast cancer cells with INM using the MTT assay and fluorescence microscopy of the live/dead cell assay. It was observed that INM exhibited good NIH/3T3 cell adhesion and proliferation and the weak inhibiting ability of MDA-MB231.

A theoretical analysis of the effect of hydrostatic pressure on cerium oxide for renewable energy applications

The characteristics of cubic cerium oxide (CeO2) have been investigated using density functional theory (DFT) using the PBE-GGA exchange–correlation functional. This study mainly focused on the structural, elastic, and optoelectronic properties of the CeO2 under the application of external hydrostatic pressure. It is observed that lattice constants and volume tend to decrease with increasing pressure. Based on the observed trends in lattice constants variations, CeO2 exhibits compressibility at high-pressure conditions, although it remains structurally unchanged throughout the pressure range of 0 to 100 GPa. Applying pressure within the range of 0 to 100 GPa reveals a distinct characteristic associated with the emergence of electronic bandgap opening. The material displays an indirect energy bandgap, with its magnitude increasing from 2.659 eV to 4.055 eV under rising pressure. To deeply understand the impact of external pressure on the optical behaviour of CeO2, extensive investigation has been conducted on several optical parameters such as the dielectric function, refractive index, optical reflectivity, absorption coefficient, optical conductivity, and loss function throughout the energy range up to 50 eV. However, there is a tendency for optical parameters to show sharpening peaks that shift somewhat towards higher energies. Furthermore, we have also tested the impact of bandgap modulation induced in CeO2 by proposing a CsSnBr3-based solar cell with the One-Dimensional Solar Cell Capacitance Simulator software. Based on our findings, the use of cubic cerium oxide may find its potential to enhance the performance of optoelectronic and renewable energy devices.

Exploring the hydrogen storage in novel perovskite hydrides: A DFT study

This work employs density functional theory calculations to investigate the structural, hydrogen storage, mechanical, electronic, optical, and bonding characteristics of perovskite hydrides KNaX2H6 (X = Mg, Ca) for potential hydrogen storage applications. Negative formation energies, positive phonon dispersions, and appropriate tolerance factor values confirm the thermodynamic, dynamic, and cubic structural stability of these compounds. KNaMg2H6 exhibits a promising gravimetric hydrogen storage capacity of 5.19%, while KNaCa2H6 shows 4.09%. Both compounds display semiconducting behavior with indirect energy band gaps of 3.31 eV and 3.17 eV, respectively. Key mechanical properties, including bulk modulus, shear modulus, and Poisson's ratio, were evaluated using computed elastic constants. The desorption temperature for KNaMg2H6, determined to be 470.4 K, renders it suitable for practical applications. Partial Bader charge analysis reveals both ionic and slightly covalent bonding interactions. Optical analysis demonstrates strong ultraviolet absorption capabilities with a redshift in the absorption spectrum. The computed properties indicate these materials hold promise for hydrogen storage applications.

Synthesis, characterization and correlation studies on the Ni–Zn–Mn ferrite as a photocatalyst

Samples of Ni0.3Zn0.7−xMnxFe2O4 (x = 0, 0.15, 0.25, 0.35, 0.45, 0.55) nanoparticles (NPs) were synthesized by auto-combustion flash method. These ferrites were used as catalysts for photodegradation of methylene blue (MB) dye utilizing visible light energy. Structural analysis was carried out using the X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, while nanoparticle dimensions were elucidated through transmission electron microscopy (TEM). The magnetic and optical behaviours were unveiled via vibrating sample magnetometer and UV–VIS spectroscopy, respectively. The XRD outcomes established the presence of a cubic spinel-type structure for the studied ferrite samples. The FTIR spectra unveiled two absorption characteristic bands of the spinel ferrite. TEM images revealed nanoscale dimensions of ferrite NPs with the range from 21.1 to 51.8 nm. The optical features exhibited an indirect band gap energy spanning from 4.25 to 4.36 eV. Magnetization behaviour displayed a sinusoidal trend corresponding to varying Mn concentrations. The ferrite NPs catalyst (10 mg) yield photodegradation efficiency ranged from 22.8 to 33.9% for 100 ml MB dye solution after 120 min of light irradiation. The effects of dye concentration and catalyst dose on the degradation efficiency were examined using the Ni0.3Zn0.35Mn0.35Fe2O4 catalyst with highest degradation (= 33.9%). On the other hand, the dependence of the degradation efficiency on the structure, morphological, magnetic and optical properties of the photocatalyst was investigated. The findings of this study underscore the potential of the prepared ferrite nanoparticles for advanced applications in environmental restoration.Graphical abstract

Biogenic synthesis of CeO2 nanoparticles via moringa oleifera seed extract: Photocatalytic and biological activity for textile dye degradation

This article presents a study on synthesizing cerium oxide nanoparticles utilizing cerium nitrate and Moringa oleifera seed extract as stabilizing and reducing agents. The XRD pattern of cerium oxide was a cubic structure with an average crystalline size of 11.92 nm. The surface feature of ceria nanoparticles has a foam-like nanostructure, type IV isotherms-mesoporous, with a 56.845 m2/g specific surface area. The UV–Vis absorbance and Tauc plot showed that the direct and indirect energy bandgap was 2.51 and 2.79 eV, respectively. TGA/DTA has established structural phase stability with corresponding mass changes by influencing bioactive molecules of seed extract in cerium nanoparticles. These nanoparticles exhibited effective antibacterial properties against S. aureus and E. coli pathogens, and the turbidimetry antioxidant properties were evaluated. Dye degradation through the photocatalyst was investigated, with the optimum degradation efficiency of 99.71 and 99.83 %, pseudo-first-order kinetics 4.62 × 10−2 and 5.07 × 10−2, respectively, for anionic-Congo red and cationic-Malachite green dye. The observed results concluded that green-mediated nanostructured ceria particles might effectively be used for antibacterial and photocatalytic purposes.

Dielectric, thermal and optical properties of PVDF-based (LaFeO3)0.5 (BaTiO3)0.5 perovskite composite films for advanced technological applications

(1-x)PVDF/(x)LFO-BTO composite films with weight percentages (x = 0, 0.05, 0.1 and 0.15) were prepared by solution casting method. Phase identification was carried out using the X-ray diffraction (XRD) technique revealing different phases (α, β & γ) of PVDF. FTIR results confirmed the presence of different vibrational modes and phases including PVDF phases. AFM and SEM were used to investigate the surface & morphological analysis, the results showed that the surface roughness increased with the concentration of LFO-BTO into PVDF films. From optical absorption spectra, the direct band gap and indirect band gap energies of the PVDF/LFO-BTO were evaluated by incorporating Tauc's relation. The composites experienced a reduction in band gap upon the addition of 0 - 15 wt% of LFO-BTO with an increasing trend in Urbach's energy. The dielectric investigations revealed elevated dielectric constant values across all composites at lower frequency ranges, attributed to interfacial polarization. Specifically, the dielectric constant of 15 % wt of LFO-BTO was found to be much higher (6 times more than the pristine PVDF). Additionally, the dielectric loss was suppressed with increasing filler concentration within the frequency range of 1 KHz to 1 MHz. Impedance spectroscopy analysis depicted a distinctive semi-circular pattern that was linked to the underlying conduction mechanism. The behaviour of ac-conductivity revealed the conduction process following the Nyquist plot. DTA-TGA analysis showed a notable improvement in thermal stability with increasing concentration in the PVDF matrix.

The interaction of light with oxygen-vacancy-rich W18O49 nanoparticles synthesized using different acid molarities for acidic and neutral water treatments

Toxic industrial compounds as a global difficulty can adversely impact people's health and the environment which motivates studies on the interaction of light and metal oxide nanoparticles to treat the water through adsorption or photocatalysis mechanism by nanoparticles. In the paper, oxygen-vacancy-rich W18O49 nanorods are successfully synthesized by a facile one-pot hydrothermal method using different molarities of hydrochloric acid (HCl) (2–12 M) as proposed candidates to treat the wastewater and solve the global difficulty related to treating the acidic water. The results declare that the change in acid molarity leads to noteworthy changes in the characteristic properties of the produced W18O49 nanorods, and the lowest acid molarity (2 M) causes the formation of uniform and pure monoclinic W18O49 nanorods with the high specific surface area (SSA) of 51.33 m2/g. Furthermore, the nanorods exhibit indirect and direct band gap energies in the range of 2.52–2.68 eV and 2.54–3.08 eV, respectively, as influenced by varying acid molarities (2–12 M). Furthermore, the impressive effects of acid molarity on the methylene blue removal efficiency of the nanorods under ultraviolet (UV) light are observed. The highest efficiency is obtained for W18O49 nanorods synthesized using the acid molarity of 2 M which can be explained by its high SSA, small band gap energy, generation of a large number of electron-hole pairs, and its efficient charge separation. The efficiencies of water treatment reach up to 99 % and 99.5 % at pH of 7 and 5, respectively, which is an excellent achievement and leads to proposing the mentioned W18O49 nanorods as an excellent candidate for treating wastewater and acid factory effluent which represents an appreciable breakthrough in addressing the issue.