Search

A series of Co-doped and Cr-doped Ba1-xCoxFe12-yCryO19 nanoparticles (NPs) were synthesized via the microemulsion route. The effects of Co and Cr substitution on the structural, dielectric, optical, and photocatalytic properties of the NPs were investigated. The Ba1-xCoxFe12-yCryO19 NPs were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, Raman scattering, and dielectric measurements. The Ba1-xCoxFe12-yCryO19 NPs were obtained in a single phase with an average crystallite size of 18 nm. The dielectric constant of the NPs decreased, while the dielectric loss and tangent loss increased with increasing dopant (Co and Cr) contents. The photocatalytic activities (PCAs) of the Ba1-xCoxFe12-yCryO19 and BaFe12O19 NPs were appraised by carrying out the degradation of CV (crystal violet) dye under solar light irradiation. The doping improved the PCA of BaFe12O19, and up to 64.23% of the CV dye could be degraded within 60 min under visible light irradiation. The Ba1-xCoxFe12-yCryO19 NPs showed great potential for application as an economic photocatalyst as they required solar light irradiation for the degradation of CV.

For a safe environment, humanity should be oriented towards renewable energy technology. Water splitting (WS), utilizing a photoelectrode with suitable thickness, morphology, and conductivity, is essential for efficient hydrogen production. In this report, iridium oxide (IrOx) films of high conductivity were spin-cast on glass substrates. FE-SEM showed that the films are of nanorod morphology and different thicknesses. UV-Vis spectra indicated that the absorption and reflectance of the films depend on their thickness. The optical band gap (Eg) was increased from 2.925 eV to 3.07 eV by varying the spin speed (SS) of the substrates in a range of 1.5 × 103–4.5 × 103 rpm. It was clear from the micro-Raman spectra that the films were amorphous. The Eg vibrational mode of Ir–O stretching was red-shifted from 563 cm−1 (for the rutile IrO2 single crystal) to 553 cm−1. The IrOx films were used to develop photoelectrochemical (PEC) hydrogen production catalysts in 0.5M of sodium sulfite heptahydrate Na2SO3·7H2O (2-electrode system), which exhibits higher hydrogen evaluation (HE) reaction activity, which is proportional to the thickness and absorbance of the used IrOx photocathode, as it showed an incident photon-to-current efficiency (IPCE%) of 7.069% at 390 nm and −1 V. Photocurrent density (Jph = 2.38 mA/cm2 at −1 V vs. platinum) and PEC hydrogen generation rate (83.68 mmol/ h cm2 at 1 V) are the best characteristics of the best electrode (the thickest and most absorbent IrOx photocathode). At −1 V and 500 nm, the absorbed photon-to-current conversion efficiency (APCE%) was 7.84%. Electrode stability, thermodynamic factors, solar-to-hydrogen conversion efficiency (STH), and electrochemical impedance spectroscopies (EISs) were also studied.

Obtaining H

To obtain good economic and environmental benefits, LaMgNi3.6M0.4 (M = Al, Mn, Ni, Co, Cu) alloys are investigated for the hydrogen storage. The absorption data of hydrogen in the tested alloys are measured experimentally at 373 K. The hydrogen absorption isotherms are analyzed using three models derived from statistical physics formalism. The adequate model permits to discover significant details about the absorption phenomenon via determining the density of the interstitial sites (Dm), the number of hydrogen atoms per site (n) and the energetic parameter ΔE. The results indicate that multi-atomic (n > 1) and multi-linking (n

In the current investigation, we report a theoretical study to acquire the highest feasible efficiency of cadmium telluride (CdTe) thin-films. It is well recognized that CdTe crystallizes in cubic zinc-blende structure and its direct band gap of 1.5 eV turned it out as a potential candidate for photovoltaic (PV) applications. Our calculations are founded on Shockley-Queisser (SQ) limit to simulate the open-circuit voltage, current density, and filling factor versus the variation of photon energy up to 4.0 eV. These key parameters of SQ change with the variation of energy between 0.3 to 3.5 eV. This is owing to the strong optical absorption (> 104 cm−1) and direct band gap of 1.5 eV, which make CdTe thin-film suitable for single junction solar cell and ideal for PV applications. It is observed that the optical absorption enhances as the thickness of the absorbed layer increases. This will effectively provide a theoretical support to the industry of global solar energy that is anticipated to be sustainable in the future.

Laser ablation synthesis in liquid solution (PLAL) is a green technique that allows for the physical formation of nanomaterials. This study indicates the preparation of stable gold nanoparticles (AuNPs) in Gum Arabic (GA) solution via laser ablation as a CT contrast agent. The optical properties were achieved using the absorption spectroscopic technique whereas the morphology and size distribution were investigated by TEM and ImageJ software. TEM image shows greater stability and spherical shape of GA-AuNPs with smaller size at 1.85 ± 0.99 nm compared to AuNPs without GA. The absorption spectrum of pure AuNPs has a lower absorption peak height in the visible range at λ = 521 nm, while the spectrum of GA-AuNPs has a higher plasmon peak height at λ = 514 nm with a blue shift towards lower wavelengths. The concentration of GA that dissolved in 10 mL of DI water via laser ablation is set at 20 mg. Increasing the number of pulses has only a minor effect on particle size distribution, which remains tiny in the nanometer range (less than 3 nm). For energies greater than 200 mJ, there is a blue shift toward shorter wavelengths. As the concentration of GA-AuNPs increases, the CT number is also increased indicating good image contrast. It can be concluded that there is a positive and significant influence of GA as a reducing agent for AuNPs, and a contrast agent for CT imaging which highlights its superiority in future medical applications.

We examine how the weak excitation regime of a quantum well confined in a semiconductor microcavity (SM) influences the dynamics of quantum coherence and the total phase. We analyze the impact of the physical parameters on different quantumness measures, and illustrate their numerical results. We show that the amount of the coherence and total phase in the SMs for multi-photon excitation can be improved and controlled by the strength of the field, exciton-photon coupling, cavity dissipation rate, and excitonic spontaneous emission rate. We illustrate how the fidelity varies depending on the physical parameters. These results might have far-reaching ramifications not just in quantum information processing and optics, but also in physics at large.

In our simulations, we considered two typical magnetic materials, while the first one includes the 3d-transition metal, such as cobalt which is responsible of the presence of magnetism in pyrochlore structure Rb3CoCl5. The second magnetic material was chosen to have 4f-rare earth metal, namely dysprosium that can induce magnetism in garnet material Dy3Al5O12. A general agreement was found between our results and the previous works. In our calculations, we employed the classical Ising model for the above mentioned realistic materials. We specifically studied the magnetic properties over a range of temperature including the critical temperature and above it. To understand the magnetic phase transition, the effect of magnetic field was involved in the classical Ising model.

We study the emission spectrum and quantum-state fidelity for an atomic system interacting with radiation fields of quantum systems described by power-law potentials. We consider a set of manifold fields that are characterizable by their level-energy differences. They include triangular, infinite, and harmonic potentials as special cases. We present the time evolution of the spectrum and fidelity for this class of potentials with respect to model parameters of the physical system. The results indicate that the spectrum and fidelity during the dynamics are highly sensitive to the value of the photon-transition number and exponent parameter.

In this paper, we investigate the emission spectrum of a two-level atomic system interacting with an optical radiation field based on photon-added coherent states of a pseudo-harmonic oscillator (PACSPHO). Also, the purity of the optical field initially prepared in the PACS-PHO is studied through the evolution of the field entropy. We examine the influence of the intensity-dependent field and the photon-transition number on the dynamic behavior of the emission spectrum and field purity. We explore the link between the field purity and the emission spectrum during the time evolution. Finally, we show how the emission spectrum is affected and changed according to the main physical parameters. We find that there is some kind of correlation between the emission spectrum and the field purity, which will be useful in different applications of quantum physics and spectroscopy.

A p-n nanocomposite based on TiO

We theoretically demonstrated optical phase switches in light storage-like experiments. Typical light storage (LS) and retrieval experiments consist of the probe field in the probe channel with writing and reading fields across the drive branch, as well as its recovery. The probe and first drive pulses as the standard electromagnetically induced transparency (EIT) effect of storing light are used in the proposed scheme for the atomic excitations. A train of probe pulses is used after a short storage period to induce Raman gain in the drive channel. The proposed scheme was applied to alkali-metal atoms such as 23Na, 87Rb, and 39K vapours. Spatiotemporal phase variations for generated drive pulses were found to shape in the form of discrete phase distributions. The proposed approach in the process of obtaining phase discrete distributions for different irradiation intensities was tested. For weak fields, the discrete distributions were distinct as a result of the differences in the upper hyperfine structure (hf) and the atomic relaxations. However, for moderate fields, the discrete phase distributions are smeared by the atomic relaxations.

Novel cubic microstructures for the purposes of plasmonic Ag-based NPs were made using biological wastes produced from a microbial culture of Bacillus cereus (B. cereus) employing a bottom-up approach for the biosynthesis of metal-based nanomaterials. The unique surface plasmon resonance (SPR) of the as-prepared Ag-based NPs was detected at 405 nm. The infra-red spectrum revealed that the used biological waste effectively stabilized our Ag-based NPs. Scanning and transmission electron microscopes were used in order to evaluate the sizes and shapes of the distinctive structures present in our samples. The Ag NPs had a face-centered cubic structure, with a size of 64.4 nm for the (200) nano-crystallites, according to the X-ray diffraction that was conducted. The zeta potential was found to be −19.5 mV and the dynamic light scattering (DLS) size was 238.8 nm. Methylene blue’s (MB) reaction with NaBH4 was used in order to measure the catalytic activity of the generated Ag-based NPs over a period of 1 to 5 min. With an astonishing reaction rate of 0.2861 min−1, the MB elimination percentage reached 67% in just 5 min, displaying outstanding catalytic activity. This work can therefore encourage the use of this biowaste for the ecologically benign, cost-effective, and long-term synthesis of innovative Ag-based nanoparticles and nanostructures, as well as in their use as catalysts in the catalytic reduction in MB.

New homologues series of liquid crystalline materials namely, (E)-3-methoxy-4-[(p-tolylimino)methyl]phenyl 4-alkloxybenzoates (I-n), were designed and evaluated for their mesomorphic and optical behavior. The prepared series constitutes three members that differ from each other by the terminally attached alkoxy chain group, these vary between 6 and 12 carbons. A laterally OCH3 group is incorporated into the central benzene ring in meta position with respect to the ester moiety. Mesomorphic characterizations of the prepared derivatives are conducted using differential scanning-calorimetry (DSC), polarized optical-microscopy (POM). Molecular structures were elucidated by elemental analyses and NMR spectroscopy. DSC and POM investigations revealed that all the synthesized derivatives are purely nematogenic exhibiting only nematic (N) mesophase, except for the longest chain derivative (I-12) that is dimorphic possesses smectic A and N phases. Moreover, all members of the group have a wide mesomorphic range with high thermal nematic stability. A comparative study was established between the present derivative (I-6) and their previously prepared isomer. The results indicated that the location exchange of the polar compact group (CH3) influences the N mesophase stability and range. The electrical measurements revealed that all synthesized series I-n show Ohmic behaviors with effective electric resistances in the GΩ range. Under white light illumination, the effective electric conductivity for the compound I-8 is five times that obtained in dark conditions. This derivative also showed two direct optical band gaps in the UV and visible light range. In addition, I-6 has band energy gaps of values 1.07 and 2.79 eV, which are suitable for solar energy applications.

Porous anodic alumina membranes coated with Pt nanoparticles (PAAM/Pt) have been employed as pH sensor electrodes for H+ ion detection. The PAAM was designed using a two-step anodization process. Pt nanoparticles were then sputtered onto the membrane at different deposition times. The membrane’s morphological, chemical, and optical characteristics were carefully assessed following the fabrication stage using a variety of analytical techniques. The potential of the PAAM/Pt sensor electrode was investigated by measuring the potential using a simple potentiometric method. The effects of depositing Pt nanoparticles for 3–7 min on sensor electrode sensitivity were examined. The optimal potentiometric Nernstian response slope for the PAAM/Pt sensor electrode with 5 min Pt sputter coating is 56.31 mV/decade in the pH range of 3.0 to 10 at 293 K. Additionally, the PAAM/Pt sensor electrode’s stability and selectivity in various ions solutions were examined. The sensor electrode had a lifetime of more than six weeks and was kept in a normal air environment.

Indium Tin Oxide (ITO) films were deposited on glass substrate using radiofrequency (RF) magnetron sputtering technique. To improve the physical characteristics of the ITO film, AlN and HfO2 buffer layers were deposited on glass prior to the film deposition. The ITO/glass, ITO/AlN/glass and ITO/HfO2/glass films were annealed using CO2 laser and electrical oven heating methods. The crystallinity of the ITO film was improved due to the incorporation of AlN and HfO2 buffer layers and also by the post-deposition annealing process. The optical transmittance of the ITO was also increased due to the presence of the buffer layers. Similarly, the annealed ITO films grown on buffer layers exhibited lower values of the sheet resistance as compared to the film deposited without buffer layers. The laser annealing technique was more found to be more effective in reducing the ITO sheet resistance.

New mesomorphic series, 4-hexadecyloxy phenyl-imino-4′-(3-methoxyphenyl)-4″-alkoxybenzoates (An), were prepared and investigated with different thermal and mesomorphic techniques. The synthesized homologous series constitutes four members that differ from each other in the terminal length of flexible chain (n) attached to phenyl ester moiety, which varies between n = 6, 8, 10, and 12 carbons. A lateral CH3O group is attached to the central benzene ring in the meta position with respect to the ester moiety. Molecular structures of all newly prepared homologues were elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic and thermal properties were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the mesophases identified by polarized optical microscopy (POM). DSC and POM examinations revealed that all members of the present series (An) exhibit a purely enantiotropic nematic (N) phase. Comparative evaluations and binary phase diagrams were established between the present homologues and their corresponding shorter one (Bn). The examination revealed that, the length of the flexible alkoxy chain incorporated into the phenylimino moiety is highly effective on the temperature range and stability of the mesophase observed. With respect to the binary mixtures An/Bn, the exhibited N phase showed to cover the whole composition range with eutectic behavior.

This work presents a study on the characteristics of the radiation attenuating behavior of oxy-fluoro borotellurite glasses with general formula TeO2–B2O3–LiF–BaO–Bi2O3. The mass attenuation coefficient (MAC) decreases pointedly as the energy goes up from 15 keV–0.15 MeV. The MAC for the tested samples lies within the range 40.032–50.170 cm2/g at 15 keV. We examined the effective atomic number (Zeff), and the results revealed that initially Zeff reaches the maximum values up to around 0.1 MeV and then Zeff decreases and reaches the minimum values between around 1 and 4 MeV. The Zeff lies within the range of 56.11–57.85 (at 15 keV). The Zeff of the tested samples increases with the increasing content of TeO2. The half value layer (HVL) was evaluated, and the effect of TeO2 and the energy on this parameter was discussed. The minimum HVL was reported at 15 keV and varied between 0.00463–0.00226 cm.

A p-n nanocomposite based on TiO2 nanotubes (NTs) and NiO nanoparticles (NPs) was designed and optimized in this study to improve the photocatalytic performance of methylene blue (MB). The hydrothermal technique has been used to produce TiO2/NiO nanocomposites with different NiO NPs weight ratios; 1TiO2:1NiO, 1TiO2:2NiO, and 1TiO2:3NiO. The crystal phase, chemical composition, optical properties, and morphology of TiO2/NiO were explored by various techniques. TiO2 NTs have a monoclinic structure, while NiO NPs have a cubic structure, according to the structural study. The bandgap of TiO2 NTs was reduced from 3.54 eV to 2.69 eV after controlling the NiO NPs weight ratio. The TiO2/2NiO nanocomposite showed the best photodegradation efficiency. Within 45 min of solar light irradiation, the efficiency of MB dye degradation using TiO2/2NiO hits 99.5% versus 73% using pure TiO2 NTs. Furthermore, the catalytic photodegradation efficiency did not deteriorate significantly even after five reusability cycles, intimating the high stability of the TiO2/2NiO nanocomposite. This suggests that the loading of NiO NPs into TiO2 NTs lowers the recombination of photo-produced electron/hole pairs and enlarged solar spectral response range, which results in improved photocatalytic activity. The mechanism of charge transfer in the TiO2/NiO and kinetic models were discussed for the photodegradation of MB.

One of the most serious environmental concerns worldwide is the consequences of industrial wastes and agricultural usage leading to pesticide residues in water. At present, a wide range of pesticides are used directly to control pests and diseases. However, environmental damage is expected even at their low concentration because they are sustained a long time in nature, which has a negative impact on human health. In this study, photolysis and photocatalysis of the pesticides dieldrin and deltamethrin were tested at two UV wavelengths (254 and 306 nm) and in different test media (distilled water, wastewater, and agricultural wastewater) to examine their ability to eliminate pesticides. TiO2 (0.001 g/10 mL) was used as a catalyst for each treatment. The purpose was to determine the influence of UV wavelength, exposure time, and catalyst addition on the pesticide decomposition processes in different water types. Water was loaded with the tested pesticides (2000 µg) for 12 h under UV irradiation, and the pesticide concentrations were measured at 2 h intervals after UV irradiation. The results showed a clear effect of UV light on the pesticides photodegradations that was both a wavelength- and time-dependent effect. Photolysis was more effective at λ = 306 nm than at λ = 254 nm. Furthermore, TiO2 addition (0.001 g/10 mL) increased the degradation at both tested wavelengths and hence could be considered a potential catalyst for both pesticide degradations. Deltamethrin was more sensitive to UV light than dieldrin under all conditions.

A quaternary glass system was fabricated via the melting quenching method. The mentioned glass system consists of five samples described by the chemical composition 50B2O3 + 30BaF2 + (20-x)Li2O + xAg2O, 0.0

The purpose of this investigation is to study the physical, structural and optical characteristics of a newly fabricated SrO2 doped lithium bismuth borate glass system. The current glass system was fabricated according to the chemical formula 50B2O3 + 25Bi2O3 + (25-x) Li2O + xSrO2, utilizing the solid state- conventional method. It was noticed that The glass density increased from 4.821 to 5.952 g cm−3 whilst the molar volume was decreasing in the range from 32.93 to 30.44 cm3 mol−1 with increase the SrO2 insertion from 0 (BBLSr0 glasses) to 25 (BBLSr25) respectively. The structure of the fabricated glasses was inspected utilizing X-ray diffraction method which clarified that the insertion of SrO2 didn’t affect the amorphous nature of the tested samples. Furthermore, the UV–vis absorption spectrum was utilized to study the UV absorption characteristics for the fabricated glasses. The UV–vis absorption spectrum showed that the absorption and transition bands increase with insertion of the SrO2 contents. Based on the UV/Vis data, several important optical features were calculated like the energy gap (Eg), Urbach energy (Eu), oscillator energy (Eo) and energy of distribution (Ed). Increasing the SrO2 substitution ratio led to increase the optical properties where the refractive index was found to increase from 3.056 to 5.710.

In the present work, the optical, electronic and thermoelectric (TE) characteristics of NaTaO3 are investigated with implementation of pressure ranging 0 to 140 GPa.The calculations were done in the framework of density functional theory (DFT) within Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) scheme implemented within WIEN2K package. The semiconducting Eg behavior of NaTaO3compound has been revealed at all applied pressures. Results indicated that the value of Eg increments from 2.29 eV (0 GPa) to 2.82 eV (140 GPa), however, the characteristics of Eg transformed to direct from indirect with the increment in pressure. The optical characteristics are also explored in the form of dielectric constants, reflectivity (R (ω)) and absorption coefficient (α (ω)). Moreover, the TE characteristics are also investigated. TE and optical features disclosed that NaTaO3 is a good candidate for optical and TE devices.

A very interesting challenge concerns the elaboration of nanowires from organic polymers with the aim to design novel nanoelectronic devices. The new VK-Stilbene copolymer based on organic nanowires was developed and characterized in this context. The VK-Stilbene nanowires were made with a template method by filling nanopores of AOO membranes. The prepared nanowires wereinvestigated by morphological spectroscopy and micro-Raman Rinshaw analysis. The modifications of photoemissive properties from microscopy film to nanowires were described by steady-state optical techniques combinedwith time-resolved photoluminescence spectroscopy. A blue shift of the luminescence are observed in the case of nanowires proceed from structural order and shortening of effective conjugation lengths. Therefore, VK-Stilbene nanowires exhibit a remarkably quasi-exponential long-lived and blue-shifted ascribed to a confinement-effect of intra-chain singlet excitons. Additionally, these nano-objects show an increase in the quantum yield with respect to bulk samples. The acquired optical data confirm that VK-Stilbene nanomaterials may be suitable for nanotechnologies.

In this research, the radiation safety features and the optical properties of novel prepared glass samples with nominal compositions 45P2O5 + 25B2O3 + 20Bi2O3 + (10-x)Li2O+xCdO where x = 0, 2.5, 5, 7.5, and 10 have been studied. The XRD was utilized to exclude the crystal structure nature of the glass samples. The density of the samples increases while the molar volume decreases with the rise of the CdO incrementation ratio. The UV-Vis NIR spectroscopy was utilized to measure the absorbance rate of the fabricated glass sample. Based on the measured absorbance, some important parameters were evaluated, such as the energy gap, Urbach energy, refractive index. The Monte-Carlo simulation code was utilized to evaluate the radiation attenuation properties of the current glass samples in the energy range 0.015 till 15 MeV.

The nanostructured materials from Ag and Au@Ag core/shell bimetallic were synthesized by pulsed infrared laser ablation process in different liquid media technique in just one-pot step. By varying the surrounding media by metallic precursor solution and the laser energy, the monometallic nanoparticles were changed to bimetallic nanocomposites in a form of core/shell structure with tuning their shell thickness. The prepared nanostructured materials were examined by different spectroscopic techniques to inform their physicochemical properties. The characterization techniques proved that the crystallinity of prepared samples. Besides, the bimetallic nanocomposite structure has a core/shell form with Au in the core and Ag in shell. Also, as the laser intensity raises, the Ag-shell’s thickness grows, and the core/shell diameter increases, which was affected in their linear and nonlinear optical properties. Their linear properties were investigated depended on Mie theory. Besides, the nonlinear optical parameters were determined by Z-scan technique, which demonstrated that the nonlinear optical properties of a shell can be tuned depending on their thickness. The prepared core/shell nanocomposites with different particle sizes confirmed the capability for possible application in optoelectronic applications as good optical limiting materials.

The first principles calculation is implemented to predict the phase stability, optical activities and magneto-electronic characteristics of cubic MAlO3 (M = Ce, Pr) perovskites. The optimized structural parameters authenticate the stability of the ferromagnetic state, and also it is confirmed by enthalpy of formation (ΔHf). Stability of MAlO3 compounds is verified with the help of tolerance factor ( τ ) in the cubic phase. The density of states (DOS) and spin polarized band structure (BS) elucidate the ferromagnetic half metallic (HM) type of MAlO3 compounds, with Ce/Pr-f states play a major role. The calculated value of magnetic moment increases from cubic CeAlO3 (1 μB) to PrAlO3 (2 μB), and Ce and Pr atoms enormously contribute in magnetization. Moreover, various optical parameters such adsorption coefficient, dielectric constants, reflectivity, optical conductivity and refractive indexare also studied. The outcomes recommend that these perovskites might be suitable candidates for optical and spintronic devices.

The present study investigates the transient spectrum (TS) of a two-level system that interacts with a generalized squeezed state without using the rotating wave approximation (RWA). We consider the purity of the optical field, which is developed in a generalized squeezed state, utilizing the linear entropy. The analytic expressions of the TS and field purity (FP) of the bipartite system are evaluated. Moreover, the study exhibits the influence of the squeezed parameter and some photons transition on the TS and FP. We obtain that the control of the FP may be generated based on an adequate choice of the photons transition and squeezed parameter. Such results can be utilized in the understanding and development of various tasks of quantum physics and optics.

This paper reports the tailored visible light emission (blue, green and white) traits of the colloidal silicon quantum dots (SiQDs) integrated with zinc (ZnSiQDs). These QDs were derived from the PSi etched with Zn powder. The ZnSiQDs was prepared via the photo-electrochemical etching process (40 mA/cm2 for 20 min) of the n-type Si wafer immersed inside the solution made from the hydrofluoric (HF) acid to ethanol (ET) volume ratios of 7:1 and 7:3 with the Zn powder (0.17 g) inclusion. The as-prepared samples (named as ZnSiQDs-7:1 and ZnSiQDs-7:3) were characterized to determine the influence of HF:ET on their structure, morphology and optical characteristics. The XPS analyses of the samples revealed the formation of ZnO. The FESEM images exhibited the growth of PSi layer of thickness 8.192 μm and 7.073 μm for the ZnSiQDs-7:3 and ZnSiQDs-7:1 samples, respectively. The EFTEM image analyses showed the nucleation of the ZnSiQDs of average diameter 2.7 nm (for ZnSiQDs-7:3) and 1.33 nm (for ZnSiQDs-7:1). The band gap energy for both samples estimated from the absorption spectra was 3.6 eV. The emission spectra of the studied ZnSiQDs under three different excitation wavelengths disclosed the intense visible peaks (blue, green and white) in the range of 385–700 nm. This observation was mainly ascribed to the effects of quantum confinement and ZnO surface layer on the SiQDs that minimized the silicon oxidation. It is established that by controlling the HF to ET volume ratio the visible luminescence of the ZnSiQDs can be customized, useful for diverse optoelectronic applications.

A new glass system with a chemical formula (60-x) B2O3+20Bi2O3 +20Li2O+ xSm2O3: x = 0, 1.25, 2.5, 3.75 and 5 wt% was synthesized using the solid-state conventional approach. The density of the newly fabricated glasses was determined using the Archimedes method. The glasses’ structure was studied utilizing the X-ray diffraction spectroscopy. Moreover, some of the most effective optical features such as the refractive index (n), energy gap (Eg), and Urbach energy (Eu) were determined based on the absorbance obtained from the UV-visible spectrum. Furthermore, the radiation shielding capacity of the newly fabricated samples was assessed utilizing the Monte Carlo Modeling (MCNP 5) code and Phy-X/PSD software. The calculated mass attenuation coefficient (MAC) values at 0.015 MeV were observed to increase from 21.893 to 25.570 cm2 g−1 for glasses BBLS1 and BBLS5 respectively. Simulations demonstrated that the MAC of the fabricated glasses enhanced with the insertion of the Sm2O3 contents. Besides, the buildup factors (EBF and EABD) were calculated using the program Phy-X/PSD. The removal cross-section ƩR for the fast neutrons was theoretically calculated. The calculated results showed the ƩR varied in the range between 0.170 and 0.241 cm-1 for glasses BBLS1 and BBLS5 respectively. The recorded results depict that the insertion of Sm2O3 enhances the optical, gamma-ray, and neutron shielding capacities.

The broadband visible photoluminescence (PL) from photoelectrochemical etched porous silicon quantum dots (PSi-QDs) containing zinc (Zn) powder is reported. The influence of the Zn content (0, 0.11, 0.17, and 0.25 g) on the structure, morphology, and room-temperature PL characteristics of the PSi-QDs were evaluated. The PSi-QDs were prepared in HF:ethanol solution by electrochemical etching of n-type Si at the optimum etching time and current density with varying masses of added Zn powder. The PL spectra of the as-prepared samples exhibited a broad emission peak in the region of 510–760 nm with the highest intensity at approximately 657 nm. The inclusion of Zn powder in the PSi-QDs was observed to enhance the PL peak intensity by a factor of seven. The improved visible light emitting traits were attributed to the quantum confinement (QC) effect, which widened the energy band gap (1.12–2.5 eV) of the Zn-included PSi-QDs. The present findings may contribute to the development of PSi-QD-based red phosphors and other optoelectronic applications. EDX and FESEM analysis showed that porous silicon etched with Zn mass is mainly composed of oxygen, fluoride, zinc, and silicon.

A novel glass system consists of six glasses was fabricated using melt quenching process according the chemical formula (60-x) B2O3+20Na2O2+20Bi2O3 +xWO3: x = 0, 1, 2, 3, 4 and 5 wt%. Archimedes method was used to determine the density and molar volume of the fabricated glasses. Moreover, the X-ray diffraction technique was used to show the variation of the amorphous phase with the addition of WO3 contents for the fabricated glasses. The optical features such as the refractive index (n), energy gap (Eg), distribution energy (Ed) and oscillation energy (Eo) were calculated based on the absorbance obtained from the UV-visible spectrum. The electromagnetic radiation (gamma ray) shielding capacity was evaluated using Monte Carlo simulation (MCNP 5) code in addition to Phy-X program. The results showed that the highest linear attenuation coefficient (LAC) occurred at 0.015 MeV and increased from 99.532 to 138.656 cm−1 for glasses coded as W 1 and W 6 respectively. The obtained results showed an enhancement of gamma ray shielding capacity with the addition of WO3 (wt%) to the fabricated glasses. Based on the estimated LAC, other shielding properties were calculated such as the glass half value layer (HVL), mean free path (MFP) and effective atomic number (Zeff). Finally, the ability of the fabricated glasses to resist the charged particles (alpha and proton) and uncharged neutrons were also estimated using SRIM program and theoretical calculation. The obtained results refer that the insertion of WO3 contents improves the shielding capacity for alpha and protons while it reduces the effective removal cross section of the fabricated glasses.

A series of six tungsten-based bismuth borate glasses with a xWO3- 20 Bi2O3- 20 Na2O2- (60-x) B2O3), 0≤ x ≤ 5 wt% chemical composition were synthesized by using the solid-state conventional method. The structures of the fabricated samples were studied with X-ray diffraction analysis. Optical features such as the energy gap (Eg), Urbach energy (Eu), steepness parameter (S), refractive index (n) and Fermi level energy (EF) were measured for the fabricated glasses with a UV–Vis–NIR spectrophotometer. Furthermore, a Monte Carlo simulation code (MCNP-5) was applied to estimate the gamma ray mass attenuation coefficient (MAC) for the fabricated glasses. The simulated data showed that the insertion of WO3 increases the MACs of the fabricated samples: the highest and lowest MACs were obtained for the W6 and W1 glasses, respectively. Then, the simulated MAC was used to calculate the mean free path (MFP) for all the fabricated glasses. The thinnest MFP was achieved by W6 (increasing from 0.007 to 70,560 between 0.015 and 15 MeV, respectively), while the thickest MFP was achieved by W1 (increasing from 0.0100 to 8.975 between 0.015 and 15 MeV, respectively). Moreover, new Phy-x/PD software was used to calculate MAC, MFP, equivalent atomic number (Zeq) and the exposure and energy absorption buildup factors (EBF and EABF). The simulated and calculated results showed that adding WO3 enhances the shielding properties of the synthesized glass.