Optical Band Gap Energy Research Articles

Facile Synthesis and Characterization of Pure and Bi-doped ZnS Nanoparticles for Photocatalytic Application

In the present research, a simple solvothermal microwave irradiation (SMI) method has been adopted for the preparation and synthesis of pure and Bi doped ZnS nanoparticles using zinc acetate, bismuth acetate, thiourea and ethylene glycol were utilized as precursors. As-synthesized pure and Bi doped ZnS nanoparticles were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX), ultraviolet-visible (UV-vis) spectroscopy and Field emission scanning electron microscopy (FESEM). From the XRD and EDAX studies, crystallite size, lattice parameter and analysis of the elemental compositions are calculated and analyzed respectively. The UV-vis spectra revealed that the optical band gap energy of pure and Bi doped ZnS nanoparticles was calculated. The FESEM shows that the average particle size spherical and agglomerated of as-synthesized pure and Bi doped ZnS nanoparticles sizes were decreased. In addition, the photocatalytic activity of pure and Bi doped ZnS nanoparticles was studied with methylene blue dye in an aqueous solution under UV light irradiation; the 5.0 mol % of Bi doped ZnS nanoparticles dye degradation efficiency of the sample was calculated as 75% in 120 minutes.

Effect of the deposition temperature on ZnCd(SSe)2 for enhance the efficiency of solar cell application

The photoelectrochemical efficiency of ZnCd(SSe)2 thin films shows a notable enhancement, increasing from 0.08 % to 0.28 %, when deposited at different temperatures (room temperature, 40 °C, 50 °C, and 60 °C). This study aims to develop ZnCd(SSe)2 thin films using a cost-effective single-step process called the Arrested Precipitation Technique (APT). This study demonstrates that varying the deposition temperatures significantly impacts the optical, structural, and morphological properties of the resulting thin films. Optical analysis shows a reduction in the optical energy band gap from 1.92 to 1.63 eV as the bath temperature increases. X-ray diffraction confirms the formation of nanocrystalline thin film samples with improved crystallinity, as indicated by the increased intensity of the (100) diffraction peak. Scanning electron microscopy reveals changes in surface morphology corresponding to different deposition temperatures. The thin films exhibit polycrystalline characteristics, as verified by transmission electron microscopy and selected area electron diffraction pattern analysis. Energy Dispersive Spectroscopy analysis identifies the presence of Cd, Zn, S, and Se elements with near-ideal stoichiometry, suggesting a favorable composition. Importantly, the photoelectrochemical performance increases significantly from 0.08 % to 0.28 % with rising deposition temperature, marking a substantial improvement with potential for further investigation and development in the field.

An innovative approach towards decolorization of tint and enhancing the optical & physical properties of high iron Na2O–CaO–SiO2 glass by co-doping with Ce4+/Nd3+: An experimental and comparative study

The aim of the research is to manufacture the colourless high iron Na2O–CaO–SiO2 glass with natural local raw materials with high iron content. Chemical and physical decolorizer like CeO2 and Nd2O3 were used in oxidation conditions by maintaining the redox of the melt. The maximum transmittance of colourless glass obtained at 546–562 nm is 91 % with a thickness of 6.5 mm. The addition of polyvalent ions Nd2O3/CeO2 decreases the optical band gap (Eg) and Urbach energy (ΔE) which results in resistance against solarization. Additionally, it also decreases the structural disorder results in high young & shear modulus. Lack of O–H in glass facilitates to retain more Si–O–Si in the glass matrices which enhances the down conversion luminance intensity of Nd3+ from 4I9/2 to 4F5/2 and improves the Far-IR behavior of the glass. Chromaticity diagram revealed that the doped glass has CI value 5416K which is closes to white light emission 5500k. Due to the presences of the Nd2O3/CeO2 and antimony oxide the Refractive index (ng), density (ρ), molar volume (V) and molecular weight of the glass increases. Maintaining the redox of the glass melt and Fe2+/Fe3+ ratio with the chemical and physical decolorizer will help to decolourize the Na2O–CaO–SiO2 glasses with the Fe2O3 content up to 0.3 % with the same methodology.

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.

A zero-dimensional 1-butylpiperazine-cadmium(II) hybrid material: Synthesis, structural analysis, and DFT studies

This study reports the synthesis and characterization of an organoammonium-cadmium(II) hybrid material, (BPH₂)₂[Cd₂Cl₈] (BP = 1-butylpiperazine), using a combination of experimental and theoretical techniques. Single-crystal X-ray diffraction shows a centrosymmetric crystal structure in the P1¯ space group, featuring a zero-dimensional (0D) arrangement where binuclear [Cd₂Cl₈]⁴⁻ anions and (C₈H₂₀N₂⁺) cations are linked by N—H···Cl and C—H···Cl hydrogen bonds. Hirshfeld surface analysis further elucidates these intermolecular noncovalent interactions, highlighting the dominant role of H···Cl contacts in the molecular packing. The crystal morphology is further investigated via the Bravais-Friedel-Donnay-Harker (BFDH) model. Infrared (IR) spectroscopic analysis was conducted to identify vibrational modes, confirm structure, and elucidate bonding features. Additionally, Experimental UV–visible study indicates an optical band gap energy of 4.75 eV, and density functional theory (DFT) calculations corroborate these findings, predicting a direct band gap of 4.45 eV. Moreover, theoretical calculations, including the complex dielectric function, band structure, and total density of states (DOS), were performed to explore the electrical and optical properties. Finally, the chemical reactivity was evaluated using conceptual-DFT descriptors at the B3LYP/SDD/aug-cc-pVTZ level of theory.

Enabling highly efficient navy-blue dye degradation over the LaFeO3/B-g-C3N4/WO3 double z-scheme heterostructure

Chemical reactivity, optical and electronic features of conventional photocatalysts can be improved by chemical modification and nanocomposites fabrication techniques. Herein, a double Z-scheme LaFeO3/B-g-C3N4/WO3 (LFO/B-CN/WO) heterostructure nanocomposite has been successfully fabricated via a hydrothermal approach. XRD, FT-IR, SEM/EDS, TEM, TGA/DSC, and UV–visible spectroscopy confirmed crystallographic planes, phase purity, and heterojunction between LFO, WO and B-CN. From UV visible absorption spectroscopy, it was confirmed that optical band gap energy of CN is remarkably reduced after boron doping. The LFO/B-CN/WO photocatalyst revealed 96 % degradation performance for Navy Blue (NB) dye after visible light irradiation for 130 min under neutral pH conditions. The data were analyzed using pseudo-first and pseudo-second order kinetics models to evaluate the dye degradation kinetics. Compared to the CN, B-CN, LFO-CN and WO-CN photocatalysts, the performance of LFO/B-CN/WO was much significant. Improved light absorption capability, effective spatial separation and prolonged charge-carrying capacity of the double Z-scheme system resulted in enhanced photocatalytic performance. This study offers new insights into the design and synthesis of highly efficient Z-scheme heterojunction photocatalysts for environmental decontamination and clean energy purposes.

Structural, morphological, optical and down-conversion studies of NaLaMgTeO6:Dy3+ single phase phosphor for white light emitting applications and solar spectral converter for photovoltaic applications

Researches on rare earth activated phosphors in solid state lighting and enhancement in efficiency of solar cells pave attention to develop efficient phosphor materials. In the present work, Dy3+ doped NaLaMgTeO6 phosphors are synthesized using solid state reaction method. The structural studies using XRD analysis confirmed the successful formation of the compound. SEM analysis reveals that the particles are closely packed, which in turn exhibit intense luminescence intensity due to low scattering and high packing density. Elemental configuration were analyzed using EDS analysis. FTIR analysis revealed the vibrational bands of the host matrix. Optical energy bandgap was calculated using DRS spectra. The luminescence characteristics of the samples were investigated using excitation and emission spectra. Upon most intense 351 and 388 nm excitation, sharp yellow emission peak at 572 nm dominates blue emission at 478 nm, further reveals that Dy3+ ions occupy low symmetry site in the host lattice. The optimum concentration of Dy3+ in the present host is x = 0.04 mol and concentration quenching is due to dipole-quadrupole interaction of adjacent Dy3+ ions. The thermal quenching phenomenon is studied using temperature dependent photoluminescence analysis. The CIE chromaticity coordinates and CCT values conclude NaLaMgTeO6:Dy3+ phosphors are good candidate for cool near-white light emitting materials for outdoor illumination. The study on solar spectral response and down-conversion property of the synthesized phosphor demonstrate its applicability as solar spectral converters in solar cell applications.

Tuning the structural and optical parameters of Li1.2Ni0.4Fe2O4 for efficient degradation of dye and pharmaceutical compounds

Sol-gel auto-combustion route was used for the fabrication of lithium and dysprosium co-doped nickel ferrite (LNDFO). The composite of LNDFO with gCN (LNDFO@gCN) was prepared via ultra-sonication method. The synthesized samples were tested by photodegrading organic pollutants. Different characterization techniques were employed to examine the structure, morphology, elemental composition, and bandgap of prepared photocatalysts. The optical bandgap energy of LNFO, LNDFO, and LNDFO@gCN was 2.92 eV, 2.73 eV, and 2.64 eV, respectively. LNDFO@gCN had the lowest recombination rate of charged species and greater surface area, which makes it an efficient photocatalyst. The degradation shown by LNDFO@gCN for panadol, MB, and phenol was 90.04 %, 93 %, and 89.5 % respectively. EIS and Mott-Schottky analysis revealed that the charge transfer resistance of fabricated composite was less than bare and doped samples, and they were n-type semiconductor materials. As compared to all fabricated photocatalysts, LNDFO@gCN was most efficient photocatalyst due to its high degradation ability, easy formation, and higher charge separation rate.

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.

Modulating Contact Electrification With Metal‐Organic Frameworks in Flexible Triboelectric Nanogenerators for Kinetic Energy Harvesting and Self‐Powered Humidity Sensing Applications

AbstractHerein, we present a novel method for fabricating a triboelectric nanogenerator using Polyacrylonitrile (PAN) on both sides as triboelectric pairs, incorporating metal‐organic frameworks (MOFs) such as ZIF‐8, ZIF‐67, MIL‐100, and HKUST‐1 during the electrospinning process. The triboelectric properties of the MOF‐incorporated fibers are thus tailored and positioned within the triboelectric series for the first time. The resulting triboelectric polarity of the composite fiber is linked to the optical bandgap energy of the PAN and the MOF/PAN composite, facilitating electron transfer between materials of different work functions and leading to enhanced output in the developed triboelectric devices. Fascinatingly, the appropriate choice of MOF filler also displayed the potential for reversing the triboelectric polarity of PAN nanofiber. Consequently, incorporating ZIF‐8 and MIL‐100 into PAN nanofibers led notably to contrasting trends in triboelectric polarity, with the pair generating an open‐circuit output voltage of 100 V, short‐circuit current of 1.35 μA, and a power density of 18.4 mW/m2 respectively. The fabricated device demonstrated effectiveness for mechanical energy harvesting applications and also as a self‐powered humidity sensor, displaying rapid response to changes in ambient humidity levels with a maximum sensitivity of 2.14 V/%RH, for relative humidity range between 50 and 90% during the humidifying cycle.

Effect of samarium oxide addition on the structural, thermal, and optical properties and photoluminescence of lithium borate glass

The samples were prepared in compliance with the form 33 Li2O–66 B2O3—(1-x) AgF—x Sm2O3, where x = 0, 0.25, 0.5, and 0.75. Powdered samples were converted to a glassy state via melting and quenching. The glassiness of the prepared samples was examined using X-ray diffraction (XRD) and Differential Thermal Analysis (DTA). From the absorption spectra of the prepared glass samples, the band gap in the optical spectrum changed slightly in the range of 3.45, whereas the Urbach energy decreased from 0.32 to 0.267 eV. The fluctuations of the optical band gap and Urbach energy can be attributed to variations in the glass structure. Sm3 + emitted intense reddish-orange light under blue and UV light excitation. There are six excitation bands in the Sm3+ excitation spectrum situated in the blue and UV regions, peaking at 361.7, 374, 400, 417, 462, and 475 nm, which are attributed to the transitions from 6H5/2 to 4D3/2, 6P7/2, 6P3/2, 6P5/2, 4I13/2, and 4I11/2 respectively. The transition from 6H5/2 to 6P3/2 had the highest intensity and was associated with a peak at 400 nm. The bright yellow, reddish-orange, and red emission bands of the Sm3+ ions in the oxide glasses are related to the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, and 4G5/2 → 6H9/2 emission transitions, respectively.

The incident photons cut-off energy, the optical linear equations and the electron phonon interactions in ZnO thin films annealed at different temperatures

The using RF-magnetron sputtering, the ZnO thin films were deposited on glass substrates at room temperature. Then using an electrical furnace in the presence of argon gas, they were annealed at different temperatures (400–600 °C). It was found that with taking Nc = 4, Za = 2, Ne = 8 for ZnO films for covalently bonded crystalline and amorphous chalcogenides, the constant β has values of about 0.37 ± 0.04 and for halides and most oxides that have ionic structure the constant β has values of about 0.26 ± 0.04 eV. It can be seen that with increasing annealing temperature absorption edge these films have a shifting behavior towards larger wavelength. Due to shifting behavior of defects distribution of atoms into films, the values of the cut-off energy, E cut-off and the λ cut-off of these films were about 3.48 eV and 355 nm, respectively. The ZnO films annealed at 500 °C specially above 3 eV have maximum value of optical density. The different linears fitting of ln (⍺) for films were obtained as y = Ex + F where 10<E < 12.5 and 14<F < 16. The ZnO films annealed at 600 °C have minimum value of electron phonon interaction (Ee-p) in a bout of 0.858 eV. The optical band gap and disordering energy plots of these films can be fitted by linear relationship EU and Eg = 0.0989–0.148 EU. We found that as deposited ZnO films have minimum value of steepness parameter σ in about of 30.93 × 10 −2eV.

A closer look at the fabrication of some doped metal ions in borophosphate glass system and their structural, elastic, optical, and gamma-ray shielding characteristics

Borophosphate host glasses doped with zinc oxide (ZnO), titanium dioxide (TiO2), tellurium dioxide (TeO2), or cerium oxide (CeO2) were synthesized using rapid quenching techniques. Fourier transform infrared (FTIR) spectra, along with deconvoluted FTIR spectra, were recorded in the 400–4000 cm−1 range. Using the models of Tauc and Urbach, the optical energy band gaps of these glasses were found to be 3.212, 3.289, 3.262, 3.087, and 2.475 eV respectively. Due to the incorporation of different metal ions into the prepared glasses, the density increased and the molar volume decreased, making the glass structure highly compact. Since the elastic moduli are directly related to the average cross-link density, the shear and longitudinal moduli show a forward proportionality with the average cross-link density. Detailed reporting focused on the mass attenuation coefficients (μm) and exposure build-up factors (EBF), crucial for evaluating the shielding properties of the material within the energy range of 0.015–15 MeV and penetration depth up to 40 mean free paths (mfp). Glass samples doped with tellurium dioxide exhibited the highest gamma attenuation due to their higher effective atomic number compared to the other samples. Compared to Portland concrete, the prepared glass composites showed higher mass attenuation coefficients across the entire investigated energy range. These results suggest that although Borophosphate glasses doped with cerium oxide have preferred mechanical properties compared with the other prepared glasses, Borophosphate glasses doped with tellurium dioxide could serve as transparent shielding material for medical applications due to their higher attenuation coefficient.

Impact of different rinsing temperatures on SnS thin films created using the SILAR technique

The (SnS) thin films were prepared by Successive Ionic Layer Adsorption and Reaction (SILAR), a versatile and simple method. The cationic and anionic solutions SnCl2.2H2O and Na2S.9H2O respectively were used as precursor materials, which will be deposited on glass substrates to study the effect of rinsing temperature on the properties of our thin films. The structural, morphological, and optical properties were investigated by using X-ray diffraction, Energy Dispersive X-ray analysis (EDX), Scanning Electron Microscopy (SEM) and spectrophotometer. X-ray Diffraction (XRD) patterns indicated that the deposited SnS thin films have an orthorhombic crystal structure. Uniform deposition of the material over the entire glass substrate was shown by Scanning Electron Microscopy (SEM). The optical band gap energy ranged from 1.5 to 1.82eV for direct transitions and from 0.6 to 0.95eV for indirect transitions.

Atomic layer deposition, mechanical, wear resistance, and optical properties of (Cr1-xAlx)2O3 films on Si (100)

This study presents the comparison of microstructure, mechanical, tribological, and optical properties of the ternary chromium-aluminum oxide films ((Cr1-xAlx)2O3) with binary Cr2O3 and Al2O3 films, deposited by atomic layer deposition at 275 °C. The atomic growth per cycle of the Al atoms increased from 3.1 to 8.5 atoms/nm2 on chromium oxide film. The Al2O3 films were X-ray amorphous. The Cr2O3 films contained crystallites of the eskolaite phase. Nano-size (diameter from 3 to 5 nm) crystallites with cubic symmetry and matching with that of cubic γ-Al2O3 or η-Al2O3 phases were observed in (Cr1-xAlx)2O3 films. The ternary film with Al/(Al + Cr) of 0.40 showed the highest hardness (18.4 GPa) and elastic modulus (169.4 GPa), whereas the wear rate of this film decreased by ∼80 % compared with Cr2O3 films. Optical band gap energy values corresponding to the indirect transition model decreased from 2.93 eV for the Cr2O3 film to 2.58 eV for the Cr-Al-O films.

CaAl1.5Fe0.5O4/6%Ni-ZnO nanocomposites: Synthesis, characterization and effective photocatalyst for the photocatalytic degradation of methylene blue dye

This study focuses on synthesizing and analyzing properties of calcium aluminate photocatalytic nanoparticles using the microwave (MW) combustion method by following the rules of green chemistry and investigates their effectiveness in the adsorption of methylene blue (MB) dye which is a crucial contaminant that enters water resources. The synthesized nanoparticles, including CaAl2O4 (CAO), CaAl1.5Fe0.5O4 (CAFO), 6 %Ni-ZnO (NZO), and CaAl1.5Fe0.5O4/6%Ni-ZnO (CAFONZO) composites, were characterized using various techniques. XRD analysis confirmed the formation of spinel structures in all samples. The crystallite size and lattice constants were determined, showing a reduction in Crystallite size of CAO from 45.98 nm to 37.55 nm after Fe3 + doping. Then, with the formation of CAFONZO Crystallite size 13.99 nm was obtained. FT-IR analysis revealed the chemical interactions between atoms in the spinel structures Nitrogen adsorption/desorption isotherms were used to determine the specific surface area of nanoparticles, pore volume, and pore size. Specific surface area of CAO, CAFO, and CAFONZO are 1.637, 1.745, and 9.903 (m2/g), respectively. SEM and TEM images provided insight into the morphology and size of the nanoparticles. According to TEM images, after Fe3 + doping, the size of particles decreased from 85 to 32 nm. UV-DRS was performed to determine the optical band gap energy of the photocatalysts. The calculated band gap values of pure CAO, CAFO, and NZO nanoparticles were 3.2 eV, 2.5 eV, and 2.7 eV, respectively. Mott-Schottky analysis indicated the type of semiconductors and the energy levels of the conduction and valence bands. Valence band (VB) values of CAFO and NZO are 2.86 eV and 2.03 eV, respectively. The photocatalytic activity of the nanoparticles was evaluated by degrading MB under visible light illumination. The adsorption studies were conducted by varying the dosage, pollutant concentration, and pH. The results showed that CAFONZO nanoparticles exhibited the highest photocatalytic efficiency, achieving 96 % degradation of MB within 120 min. The combined photocatalyst demonstrated improved efficiency compared to the individual components.

Scaling up features of photocatalytic degradation and radiation shielding of multicomponent Cr–Co–Zn nanoferrites

Optical, photocatalytic activity, and radiation shielding studies were conducted on CrxCo0.8Zn0.2Fe2-xO4 (0.0 ≤ x ≤ 0.1, Δx = 0.02) nanoferrites for water treatment and radiation shielding applications. The optical absorption analysis revealed that the optical band gap energy values range from 1.864 to 1.803 eV as assessed through Tauc plots. Further analysis of photocatalytic degradation showed that the Cr0.06Co0.8Zn0.2Fe1.94O4 sample exhibited superior methylene blue (MB) dye removal compared to other samples, with an efficiency of 96.74% in 60 min. Additionally, the present nanoferrites exhibited excellent stability in photocatalytic degradation over multiple cycles. The study also investigated the linear attenuation coefficient (LAC) of the current ferrite nanoparticles, demonstrating increased LAC values with higher Cr content, while the half value layer (HVL) diminished with further Cr concentration. The HVL values indicated the potential efficacy of our nanoferrites as radiation shields when compared to standard radiation shielding materials. Overall, this research suggests a new direction for optimizing spinel nanomaterials for applications in water treatment and radiation shielding.

Investigation of structural, optical, and magnetic properties of NiFe2O4 for efficient photocatalytic degradation of organic pollutants through photo fenton reactions

Nowadays, water pollution generated from textile effluents is one of the major problems for the human race and ecology. Hence, development of sustainable strategies to lower the water pollution level has become a burning need. In this regard, the present study focuses on the preparation of nano catalyst NiFe2O4 to catalyze the chemical reactions on industrial organic dyes for their fast cleansing from water. By sol-gel auto-combustion technique, NiFe2O4 nanoparticles were synthesized and exposed to thermal process at temperatures of 400, 600, and 800 °C. Highly crystalline phase with spinel cubic structured NiFe2O4 was formed with a crystal size of 18.71 nm, which was confirmed by XRD analysis. The FTIR spectra showed two fundamental absorption bands in the range 597.80–412.59 cm−1, which are the characteristics of tetrahedral M − O and octahedral M − O bond in NiFe2O4. The surface morphology of calcined NiFe2O4 was investigated by scanning electron microscope (SEM). The nanoparticle size analyzer exhibited that the synthesized NiFe2O4 nanoparticles had an average particle size of ∼ 291.3 nm. Three stage decomposition patterns were observed for NiFe2O4, which was analyzed by a temperature programmed STA. Zeta potential analyzer showed that the synthesized sample S1 and S2 were stable in the dispersion medium. Also, NiFe2O4 exhibited optical band gap energies for direct band transitions within the visible spectrum measured to be 1.43–1.45 eV, rendering them effective as photocatalysts under sunlight. The samples showed magnetic measurements by VSM with saturation magnetization, coercivity, remnant magnetization value of 66.81 emu/g, 4.13 Oe and 12.94 emu/g, respectively. The synthesized photocatalyst, NiFe2O4, at 400 °C, significantly degraded three toxic organic pollutants—Methylene blue, Rhodamine B, and Congo Red—under visible light through ‘Photo-Fenton’ reaction mechanisms. Among the three dyes, Methylene Blue exhibited the highest degradation percentage with a rate constant of 0.0149 min−1 and followed pseudo-first-order kinetic model.

Impact of hydrogen plasma treatment on ITO substrate for enhanced performance of CdS/CdTe solar cells

The indium tin oxide (ITO) film was treated with 100 W-power hydrogen plasma for 5 min before being used as a substrate to fabricate thermally evaporated CdS thin films. The structural, optical, and electrical properties of ITO and grown CdS films affected by pre-deposition plasma treatment were studied. SEM images show that the surface of ITO film becomes smoother after treatment. AFM analysis determines a decrease and increase in the surface roughness of ITO and CdS thin films after treating the ITO substrate. The XRD patterns show an improvement in the crystallinity of the fabricated thin films. Increasing the optical energy bandgap up to 3.699 eV and.2.481 eV for ITO and deposited CdS films respectively. So, design simple CdS/CdTe solar cells at a device temperature of 300 K. Enhancing the photovoltaic parameters and an increment of about 20 % in solar cell performance.

Insight into deposition duration-varied crystallinity, optical parameters, morphology and electrical properties of solution-processed nanostructured CdSSe thin films

Nanostructured cadmium sulpho selenide (CdSSe) films have been grown onto glass substrates for different deposition durations via a facile solution-based method known as chemical bath deposition (CBD). XRD studies revealed that the crystallites in the films possessed hexagonal (wurtzite) structures with predominant orientation along the (002) plane. The crystallite size increased from ∼5.95 nm to ∼16.69 nm with the increase in deposition duration from 1 h to 4 h. The absorbance, transmittance and reflectance measurements were carried out. A transparency of ∼(50–80) % was obtained for the films. The direct optical energy band gap was found to decrease from 1.982 eV to 1.952 eV with the increment of deposition duration from 1 h to 4 h. SEM micrographs of the films revealed the presence of nano spherical-shaped grains with an average size ranging from ∼305 nm to ∼612 nm. HRTEM images illustrated the presence of compact nano-spherical grains and nano-crystallites distributed in random orientations. Raman spectroscopy divulged the presence of CdSe and CdS vibrational Raman modes and overtones in the films. PL spectra revealed a prominent red emission band along with weak luminescent bands in the yellow-red emission region. The presence of Cd–Se and Cd–S bonds in the films was validated using FTIR analysis. Electrical investigation revealed the linear current‒voltage relationship for the films with the rise in conductivity with deposition duration. Hence, deposition duration stands out as a vital parameter for modulating the properties of CdSSe thin films for use in photovoltaic devices and optoelectronics.