Optical Band Research Articles

Synthesis of a novel bismuth molybdite/iron oxide thin film for oxytetracycline degradation in a photoelectrocatalytic system

In this study, heterostructures based on Bismuth molybdite/iron oxide (Bi2MoO6/Fe2O3) thin films were fabricated by a dip-coating technique using precursor solutions. The heterostructures were deposited on fluorine-doped tin oxide glass substrates. From a detailed characterization using X-ray diffraction and X-ray photoelectron spectroscopy, the formation of the orthorhombic phase for Bi2MoO6 and the co-existence of hematite and maghemite in Fe2O3 was demonstrated. Meanwhile, the field emission scanning electron microscopy cross-section images confirm the formation of well-defined Bi2MoO6 film under the Fe2O3 deposition. The optical band gap energies for the heterostructure obtained were estimated from the diffuse reflectance spectra and ranged from 2.3 to 3.5 eV. Photoluminescence analysis revealed an improved separation and faster transfer of photogenerated electrons and holes for the Bi2MoO6/Fe2O3 (Het) film. The best oxytetracycline (OTC) removal percentage through photoelectrocatalytic treatment was 96.85% using the Het. Besides, were carried out the variation of parameters which affect the OTC photoelectrocatalytic degradation as pH, potential applied, and scavenger assay. The 1O2 was the oxidant predominate, which attack the OTC ring to initiate and accelerate the degradation process. Based on the analysis of degradation intermediates and characteristics of Bi2MoO6/Fe2O3, possible degradation pathways and mechanisms of OTC were displayed. An enhancement of oxytetracycline degradation efficiency of Het fabricated compared to pristine oxides was achieved mainly due to avoid the charge recombination of photogenerated electron-hole pairs provided by Direct Z-scheme heterostructure. Finally, the Het fabricated represents a promising material for efficient and sustainable pharmaceutical removal applications.

Enhancement of the photodegradation performance towards methylene blue and rhodamine B using AgxSn1–xO2 nanocomposites

In the present study, the structural properties, as well as the photodegradation performance of methylene blue (MB) and rhodamine B (Rh B) using hydrothermal synthesized AgxSn1–xO2 (0 ≤ x ≤ 1) nanocomposites were studied. The study was investigated using various techniques including EDS, XRD, FE-SEM, HR-TEM, photoluminescence spectroscopy, N2 adsorption-desorption, GC-MS, and a double-beam spectrophotometer. The tetragonal SnO2 phase dominates, while the cubic Ag2O phase appears at larger x ratios (x ≥ 0.5). The crystallite and particle sizes were slightly raised for a low Ag ratio but dramatically increased for higher x ratios. Different morphologies emerge depending on the composition, such as spherical and irregular particles for x = 0 and 1, sheet-like morphology for x = 0.05, 0.2, and 0.4, and worm-like morphology for x = 0.5. The maximum surface area was calculated using the BET method to be 358 and 354 m2/g for x = 0.2 and 0.4, respectively. The direct optical band gap depends on the x ratio and the crystallite size and equals 3.95eV and 3.70eV for x = 0 and x = 1, respectively. The synthesized AgxSn1–xO2 composites demonstrated excellent photodegradation efficiency (η) towards MB and Rh B. The majority of compositions had high η towards MB and the highest value of 99.6% was attained using Ag0.4Sn0.6O2 under the UV-visible irradiation for 1.5h. Also, synthetic composites demonstrated efficient photodegradation of Rh B, particularly for higher Ag content (η = 94.4% at x = 0.5). The catalysts revealed acceptable reusability and stability, and the degraded products were studied using the GC-MS technique with a proposed mechanism of degradation. The improvement in photodegradation of MB and Rh B dyes can be attributed to an increase in surface area, as well as the development of shape and optical characteristics.

Impact of TBAI Doping on the Optical and Dielectric Features of PVC/MoO3/NiMoO4/PANI Polymer Composite for Optoelectronic and Energy Storage Applications

Poly (vinyl chloride, PVC)/MoO3/NiMoO4/polyaniline (PANI)/x wt% tetrabutylammonium iodide (TBAI) polymers were formed using casting and hydrothermal methods. The present study examined the nanocomposites’ structural, electrical, and optical features comprising PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers. X-ray diffraction and scanning electron microscopy were used to investigate the structure and morphology of different samples. The influence of different amounts of TBAI on the linear and nonlinear optical features of PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers was explored. Adding MoO3/NiMoO4/PANI.TBAI reduced the direct and indirect optical band gaps to their minimum values (3.88, 3.04) eV and (3.58, 2.13) eV, respectively. Doped polymer with MoO3/NiMoO4 has the highest refractive index value. Only PVC filled with MoO3/NiMoO4 exhibits the highest non-linear optical parameters within the visible range. The fluorescence intensity and emitted colors influenced by the kind of dopant. The dielectric constant and ac conductivity values of the host polymer were affected by the amount of TBAI. The maximum energy density value was observed in PVC/MoO3/NiMoO4/PANI/10 wt%TBAI polymer. The Cole-Cole plot demonstrated an irregular shift for doped samples relative to the undoped. The obtained results nominated the nanocomposite films of PVC/MoO3/NiMoO4/PANI/x wt%TBAI to be used in diverse electric and optoelectrical applications.

Synthesis of CuO/Fe3O4 Nanocomposite for enhanced solar thermal desalination

Nanoparticle (NPs) have attracted the attention of scientists and researchers in water remediation due to the improvement in its processability, and its cost effectiveness. The present work analyzed the synergistic effect of CuO (NPs) with different ratios (0, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 wt %) on the structural, and optical properties of Fe3O4 (NPs), that can be used in water desalination process. The general methodology for preparation and structural properties of CuO (NPs), Fe3O4 (NPs) and CuO/Fe3O4 (NCs) were analyzed by (XRD) and (TEM) measurements. The morphological combination of (SEM) with (EDX), were used for determining the elemental identification of CuO/Fe3O4 (NCs). The characterization topography was found to be strongly affected by the change of the CuO concentration. Furthermore, the Urbach energy (EU), steepness parameter (σ), electron-phonon interaction (Ee-p), optical band gap (Eg), refractive index (n) and optical conductivity (σopt) were calculated. The optical absorption studies in the UV–Visible region, revealed that the CuO/Fe3O4 (NCs) was found to be direct allowed transition, and the energy bandgap value decreased from 2.52 eV to 2.15 eV based on the percentage change of CuO (NPs) in CuO/Fe3O4 (NCs). Moreover, the value of thermal conductivity (k), and thermal efficiency (η), showed an increase with the increase of the ratio of CuO (NPs), which may be an indication for opening an innovation way that can satisfy the need of seawater desalination technology.

Varying linear polarisation in the dust-free gamma-ray burst 210610B

Context. Long gamma-ray bursts (GRBs) are produced by the collapse of some very massive stars, that emit ultra-relativistic jets. When the jets collide with the interstellar medium they decelerate and generate the so-called afterglow emission, which has been observed to be polarised. Aims. We study the polarimetric evolution of the GRB 210610B afterglow, at z = 1.1341. This allows us to evaluate the role of geometric and/or magnetic mechanisms in the GRB afterglow polarisation. Methods. We observed GRB 210610B using imaging polarimetry with CAFOS on the 2.2 m Calar Alto Telescope and FORS2 on the 4 × 8.1 m Very Large Telescope. Complementary optical spectroscopy was obtained with OSIRIS on the 10.4 m Gran Telescopio Canarias. We studied the GRB light-curve from X-rays to the optical bands and the Spectral Energy Distribution (SED). This allowed us to strongly constrain the line-of-sight extinction. Finally, we studied the GRB host galaxy using optical to NIR data to fit the SED and derive its integrated properties. Results. GRB 210610B had a bright afterglow with a negligible line-of-sight extinction. Polarimetry was obtained at three epochs: during an early plateau phase, at the time when the light curve breaks, and after the light curve steepened. We observe an initial polarisation of ∼4% that goes to zero at the time of the break, and it then again increases to ∼2%, with a change in the position angle of 54 ± 9 deg. The spectrum shows features with very low equivalent widths. This indicate a small amount of material in the line of sight within the host. Conclusions. The lack of dust and the low amount of material in the line of sight to GRB 210610B allowed us to study the intrinsic polarisation of the GRB optical afterglow. The GRB polarisation signals are consistent with ordered magnetic fields in refreshed shock or/and hydrodynamics-scale turbulent fields in the forward shock.

Optical properties analysis of gelatin-based prepared Co, Ni, and Mn-doped ZnO nanoparticles in infrared and UV–vis region using Kramers-Kronig methods

This study investigates the structural, optical, and morphological properties of ZnO nanoparticles doped with Ni, Mn, and Co (Zn0.97A0.03O where A = Ni, Mn, and Co, designated as ZN, ZM, and ZC, respectively). X-ray diffraction (XRD) analysis confirms the successful incorporation of dopants into the ZnO lattice without altering its wurtzite structure. Field emission scanning electron microscopy (FESEM) images reveal that doping results in larger and more uniformly distributed particles. Energy-dispersive X-ray spectroscopy (EDX) verifies the presence of Ni, Mn, and Co in the respective samples. Fourier transform infrared (FTIR) spectroscopy indicates an increase in average phonon energies due to doping, as evidenced by the shift in the Zn-O vibration peak. Ultraviolet–visible (UV–vis) spectroscopy shows that doping causes a blue shift in the absorbance peak and increases the optical band gap from 3.17 eV for pure ZnO to 3.22 eV for Co-doped ZnO. Transmission electron microscopy (TEM) and corresponding EDX results further confirm the presence of dopants and illustrate that doped ZnO nanoparticles are larger than pure ZnO particles. These findings provide valuable insights into the impact of doping on ZnO nanoparticles, potentially enhancing their suitability for various technological applications.

Catalyst efficiency through the disorder kinetics to identify its nonlinearity in their properties of Ag3PO4@TiO2 catalyst using UV–visible spectroscopy

Abstract Photocatalysis has a significant role in water remediation. During the process of photocatalysis, catalysts face different problems, such as instability and inefficiency. Here, we are introducing a new method, ‘nonlinearity kinetics’, which will help to identify this kind of problem during photocatalytic activity. We are considering Ag3PO4@TiO2 to study nonlinear disorder kinetics. Ag3PO4 is a highly photoactive compound with an inherent photocorrossive nature. Here, it addresses the challenge of pure Ag3PO4 by transforming composite materials to Ag3PO4@TiO2 and by studying its nonlinear kinetics during photocatalysis. The Ag3PO4@TiO2 underwent preliminary characterisation. Increment of crystalline nature studied through XRD. FESEM and TEM analysed morphological alignment and diffraction patterns. The functional behaviour of oxygen, Ag, Ti and P–O–P were identified through the FT-IR spectra. The reduced optical band gap Ag3PO4@TiO2 was 2.9 eV Obtained from the UV–visible spectra. Photocatalysis activity was performed, and newly introduced disorder kinetics were observed. The nonlinear fit of the kinetics shows a shift over time (intercept value of linear fit −0.27) that indicates the corrosive characteristics. For an efficient catalyst, this value must be equivalent to zero. The photocorrossive disorder kinetics study demonstrates the disorder and nonlinearity of the catalyst and catalytic medium when it does not fit with a linear fit. To identify a disorder, it is important to look at the disorder kinetics of analysis.

Exploring the nature of an ultraluminous X-ray source in NGC 628

Aims. In this work, we study the X-ray spectral and temporal properties of an ultraluminous X-ray source (ULX) in NGC 628 by using multi-epoch archival X-ray data. The physical parameters were estimated in each epoch in order to constrain the nature of the compact object in the system. Also, the optical counterpart candidates of the ULX were examined using the archival Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) data. Methods.XMM-Newton, Chandra, and Swift data were used to create the long-term light curve (which covers a period of 22 years) and perform the spectral analysis. Lomb-Scargle periodograms of the source were constructed to examine the short-term variability in each epoch. In order to search for an optical counterpart in the HST/WFC3 images, a relative astrometric correction was initially applied to the Chandra and HST/WFC3 images. Results. The X-ray flux of the source changes by a factor of ∼200 throughout the observations. The previously detected quasi-periodic signal (in the range of 0.1−0.4 mHz) was confirmed by using the Lomb-Scargle method. After astrometric correction, two optical counterpart candidates were detected for the source. The obtained spectral energy distributions in the optical band for both candidates indicate that the optical emission is dominated by the irradiation of the accretion disc. Considering the best-fit model parameters of the multi-colour disc black-body model, we derived the mass of the black hole in the system as being in the range of (5−28) M⊙. Nonetheless, the long-term variability and the spectral transitions in the hardness–luminosity diagram make it difficult to rule out the neutron star scenario.

Synthesis, Characterization of KNb0.99Eu0.01O3 and improved Photo-catalytic H2-Production on Ag/La2NiO4/ KNb0.99Eu0.01O3 hetero-junction

The perovskite KNb0.99Eu0.01O3 prepared by nitrate combustion is applied as a hydrogen photocathode in heterojunction with La2NiO4 under visible light. The XRD pattern confirms the formation of KNb0.99Eu0.01O3 structure with orthorhombic single phase. The SEM images present grains between 0.2 and 0.4 µm while the optical band gap (3.14 eV) is calculated from the diffuse reflectance. Under illumination, the cyclic voltammetry (CV) and the capacitance measurements in Na2SO4 electrolyte show an increased current below ∼ -0.7 V vs. Ag/AgCl and p-type behavior with a conduction band (CB = −1.95 V) cathodically positioned with respect to H2 level, thus leading to H2 photo-production. The hetero-system La2NiO4/KNb0.99Eu0.01O3 shows a much higher activity than KNb0.99Eu0.01O3 where efficient H2-photoevolution occurs with concomitant oxidation of S2O32−, as reducing agent. So, the co-junction of La2NiO4 with KNb0.99Eu0.01O3 facilitates the charge transfer and increases the reaction efficiency. At neutral pH, the H2 evolution rate for the photocatalysts KNb0.99Eu0.01O3 and La2NiO4/ KNb0.99Eu0.01O3 are 11.15 and 57 µmol g−1 min−1; respectively. Further enhancement is observed with Ag-loaded La2NiO4/KNb0.99Eu0.01O3, reaching a maximum hydrogen production rate of 67 µmol g−1 min−1, attributed to the lower overpotential introduced by Ag. These findings highlight the potential of the ternary system Ag/La2NiO /KNb0.99Eu0.01O3 as an efficient photocathode for H2 generation.

Preparation, characterization and biological activity of Co-doped ZnO nanostructured thin film: A comprehensive study on its photo-physical properties and antimicrobial efficacy against food-borne pathogen

The Co@ZnO thin film deposited on glass substrate with dopant contents of cobalt ranging from 0 to 10 % were fabricated using spray pyrolysis coating method. The prepared nanocomposite thin film was characterized by scanning electron microscopy, X-ray diffraction, UV–vis and Raman spectroscopy. Some surfaces structural probing of the deposited samples confirmed nanolamination of hexagonal wurtzite phase of ZnO with no other impurity phases and high adherence on the soda lime glass substrate. Average grain sizes (56–43 nm) and lattice strain of the films were found to be tailored with the variation of Co-dopant content, signifying phonon confinement or defect/disorder caused by the Co-dopant impurity on the ZnO host particle owing to the impurity levels and oxygen vacancy states. The film demonstrated high optical transmittance with enhanced photoabsorbtion and narrow optical band gap (3.24–2.64 eV) with increasing Co-dopant content. In evaluating its antibacterial efficacy, the Co@ZnO thin film was tested at different dopant concentration against Bacillus cereus (foodborne pathogen). The result revealed that the films exhibits excellent inhibitory effect on the pathogen, with highest activity obtained at 10 % Co@ZnO. Furthermore, a more improved inhibitory activity was recorded when at 10 % Co@ZnO dopant was exposed to UV irradiation.

Explication of the luminescent and optically active RE3+ triply-doped silica phosphate glass films for photonic applications

The multi-component silicate glass films triply-doped with Er3+/Yb3+/Nd3+ were fabricated by spin coating technique. X-ray diffraction revealed a cristobalite phase in the glasses doped above 0.6 mol% of Nd3+. The transparency of the films increases with the addition of the co-dopant, due to the increase in optical band gap by the Burstein-Moss shift. The high value of the correlated color temperature of the blue emission indicates enhanced visual perception, suggestive of cool blue film lasers. The red emission from upconversion exhibits potentiality for flat display panels. The gain cross-section of the glass with 0.6 mol% of Nd3+ was 13.54 ×10−20 cm2 which makes it ideal for NIR film lasers in the S-band region. The Inokuti-Hirayama model predicts luminescence quenching due to dipole-dipole interactions in the glasses co-doped beyond 0.6 mol% of Nd3+. The 4F9/2→4I13/2 transition observed in the films, suggests their suitability for O + E + S band NIR film lasers in telecommunication sectors.

Inflated electronic and optical assessment of gC3N4/ZnO nanocomposite as a potential emissive layer material for OLED application

Organo-inorganic nanocomposite materials have been proven to be novel hybrid materials with inflated electronic and optical performance that can be tailored with the judicious selection of the building units or their combinations. Here, hydrothermal, thermal polycondensation, and ultrasonication techniques were used to synthesize pure ZnO, gC3N4, and gC3N4/ZnO with varying weights % such as 10%, 15%, 20%, and 25% of ZnO inorganic filler elements in gC3N4 matrix. The crystalline phase (hexagonal wurtzite) and crystallite size (10.0 nm, 17.6 nm, and 15.90 nm) of the synthesized materials were examined by X-ray diffractometer. The FESEM and HRTEM characterizations revealed the sheet-like gC3N4 and spherical-type ZnO nanoparticle-like microstructures of the samples. The present functional groups, corresponding vibrational frequency, chemical states, and binding energy were investigated using FTIR and XPS spectroscopic methods. Optical parameters such as optical band gap energy (Eg = 3.24 eV), Urbach energy (Eu = 0.41 eV), refractive index (n= 1.99), emission quantum yield (∼ 69.03%), and color purity of the nanocomposites were examined using UV visible and photoluminescence spectroscopic techniques. IV and Hall measurements techniques were used to determine the semiconducting parameters of the optimized sample, such as conductivity (∼62.90×10−5 S/cm), carrier mobility (∼ 44.1 cm2/Volt. Sce), carrier concentrations (∼1.825×1014 cm−3), and sheet resistance (∼1.062×103 Ω/cm2). Due to their excellent optical and electrical behavior, the nanocomposite materials were found to be fairly suitable as a potential emissive layer material for OLED applications.

A systematic evaluation of Random Lasing, Third Harmonic Generation, and quantum chemical calculations in multifunctional perylene derivatives

The quest for multifunctional materials in the field of optoelectronics has become increasingly imperative, as it offers a pathway toward the development of highly versatile and efficient devices. In this study, we present a comprehensive overview of our achievements in the characterization of perylene derivative-based materials. This group of chromophores exhibits remarkable multifunctionality including Third Harmonic Generation (THG), Z-scan results, and excellent Random Lasing (RL) capabilities. Theoretical quantum chemical calculations (QCC) were conducted to investigate dipole moments, frontier molecular orbital HOMO and LUMO energies, optical band gap energies, as well as second hyperpolarizabilities (γ). The study revealed how groups attached to the perylene core influence the chromophore's dipole moment and, consequently, the nonlinear optical (NLO) properties of the investigated compounds. The combined theoretical and experimental analyses provide valuable insights for the design of various optoelectronic devices using thin films of perylene derivatives, enhancing the understanding of their nonlinear and laser action behavior.

Effect of Al doping on the structural, optical and photocatalytic properties of sol-gel spin-coated NiO thin films

Nanostructured NiO thin films are renowned for their catalytic activity and potential for degradation of industrial effluents. In this study, Al-doped NiO (Ni1-xAlxO with x = 0, 0.02, 0.04, 0.06, and 0.08) thin films were synthesized by sol–gel spin coating, and the influence of Al doping on their physical properties, surface morphology, optical band gap, and photo-catalytic performance was investigated. X-ray diffraction (XRD) analysis confirmed the high crystallinity of the thin films and revealed a pronounced doping effect on parameters such as crystallite size, microstrain, and dislocation density. Scanning electron microscopy (SEM) revealed the formation of spherical nanoparticles with particle sizes ranging from 26 nm to 11 nm. The elemental composition was verified through energy-dispersive x-ray (EDX) analysis. The optical bandgap of the prepared films was determined through UV-visible spectroscopy. The Ni0.98Al0.02O films exhibited the lowest PL intensity, indicating a reduced recombination rate. To assess the photo-degradation capability of the prepared thin film catalysts, industrial effluent Indigo Carmine was employed as a test compound. The Ni0.98Al0.02O sample demonstrated the highest degradation efficiency, achieving about 96% degradation within 2 h of UV–vis light irradiation. Furthermore, the degradation followed pseudo-first-order kinetics.

Effect Of Annealing Temperature On The Optical And Structural Properties Of Zinc-Doped Cd2SnO4 Thin Films Prepared By Dip-Coating Method

As demand for solar PV modules steadily increases studies on cheaper alternative TCO materials, with low resistivity and high transmittances in the visible spectrum to replace ITO are been undertaken. Among TCO materials considered as alternative to Indium Tin Oxide (ITO) is Cd2SnO4, owing to its availability in large quantities at relatively lower costs. Studies on optical properties of N2 and F2 doped Cd2SnO4 films have revealed increased transmittance 99%, and reduced band gap 3.3 eV. On the other hand Fe doped films have been observed to exhibit higher refractive indices, extinction and absorption coefficients with lower transmittance and optical band gap. Although studies have been carried out on Zinc doped Cd2SnO4 films, the effect of annealing temperature on the properties of the films have not been reported. This study investigated the effect of annealing temperature on the optical and structural properties of Zinc-doped Cd2SnO4 films. Thin films of Zincdoped Cd2SnO4 were prepared by mixing 0.1 M Cadmium Acetate with 0.1 M Tin II Chloride in ratio 1:1 to prepare Cd2SnO4 which was doped with 0.1 M Zinc Nitrate then dip-coated on clean glass substrates. The coated substrates were dried at room temperature and annealed in air the films annealed at 350 o C, 400 o C and 450 o C for 90 minutes Optical transmittance and reflectance were measured in wavelength range 200-1200 nm and with the results: prominent XRD peak oriented in the (2 0 0) direction, transmittance of 78.7% at 700 nm wavelength, absorption coefficient of 3.891 - 5.591 x 104 cm-1 , extinction coefficient of 0.1852 - 0.2126, refractive indices of 1.983-2.121 at 588 nm wavelength and band gap values range 3.45-3.65 eV. Annealing was observed to reduce refractive index and does not affect transmittance therefore doesn’t enhance suitability of films as TCO materials for Photovoltaic applications.

Hydrothermally synthesized Sr-doped In2S3 microspheres for efficient degradation of noxious RhB pollutants in visible light exposure

A series of SrxIn2-xS3 (x = 0, 2, 4, 6 and 8 mol%) microspheres have been prepared at 160°C using hydrothermal approach and examined the impact of Sr doping on its structural, morphological, optical and photocatalytic properties. Structural properties have been investigated using X-ray diffraction (XRD) with Rietveld refinement. Morphology and elemental composition have been analysed using Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray Spectroscopy (EDX), respectively. Optical band gap energy (Eg) has been determined using Diffuse reflectance Spectroscopy (DRS) and found to range between 2.15 eV to 2.07 eV. Photoluminescence (PL) emission spectra confirm a decrease in charge carrier recombination rate with Sr doping. The negative surface potential has been assessed by the Zeta analyzer, which indicates its suitability for the degradation of cationic dyes such as Rhodamine-B (RhB). Among the SrxIn2-xS3 microspheres, Sr0.04In1.96S3 demonstrated highest photocatalytic efficiency ∼98 % degradation of RhB pollutant (10 ppm) in 240 min. using 10 mg of catalyst per 100 ml. The adsorption kinetics in the presently studied samples obeys the pseudo 2nd order kinetic model. This study highlights the significant impact of Sr doping on the photocatalytic efficiency of SrxIn2-xS3 microspheres, offering promising applications in removal of RhB dye.

A Comparative Study of the Linear/Nonlinear Optical, and Dielectric Properties of PVA/CMC/(1−x)ZnWO4−xPbS Blended Polymers for Optoelectronic Applications

An analysis was conducted on the optical, structural, and dielectric characteristics of PVA/CMC/(1−x)ZnWO4/xPbS blends. The structures of the filler samples, undoped, and doped blends were examined using X-ray diffraction. The crystallite sizes of the various phases in the filler samples are affected by the amount of PbS in the nanocomposite. The morphologies of different blends were explored using scanning electron microscopy. The doped blend exhibited superior absorption of Ultraviolet A (UVA) and Ultraviolet B (UVB) types in addition to the visible spectrum. The optical band gaps were minimized to (5.37, 5.56, 4.11) and (4.76, 3.14, 2.92) eV for direct and indirect optical transitions, respectively, when the PVP/CMC doped with nanocomposite had 10% PbS. The highest refractive index, optical dielectric constant,and nonlinear optical parameter values were achieved when the blend was loaded with ZnWO4 only while the highest optical conductivity was obtained as the blend contained 15% PbS. The highest fluorescence intensity was observed when the fillers did not contain PbS, and it decreased as the concentration of PbS in the filler increased.

Effects of cadmium doping on the physical and sensing properties of nanostructured CuO thin films

This investigation used sol-gel deposition to create undoped CuO and CuO: Cd thin films. All films of undoped CuO and CuO: Cd phase exhibit four dominating peaks at 35.52°, 38.84°, 53.37°, and 68.23°, which are correspondingly assigned to the (022), (200), (020), and (220) planes, according to X-ray diffraction analysis. The dislocation density reduced from 60.55 to 49.94, the strain decreased from 26.98 to 24.60, and the grain size of the produced films measured by XRD was 12.85–14.15 nm. Atomic force microscopy (AFM) was used to study the morphology. SEM analysis showed increased aggregation with higher Cd content, resulting in a more uniform porous structure. The optical band gap decreases for all samples as the cadmium content increases, ranging from 2.28 to 2.14 eV. Similarly, the refractive index and extinction coefficient values decrease as the cadmium content increases for all samples. The gas sensor detects H2 (375 ppm) using CuO film cadmium doping, which enhances sensitivity, CuO: 4% exhibits highest resistance. Sensitivity decreases with higher doping, indicating reduced sensor responsiveness.

Extragalactic globular cluster near-infrared spectroscopy

Context. One way to constrain the evolutionary histories of galaxies is to analyse their stellar populations. In the local Universe, our understanding of the stellar population properties of galaxies has traditionally relied on the study of optical absorption and emission-line features. Aims. In order to overcome limitations intrinsic to this wavelength range, such as the age-metallicity degeneracy and the high sensitivity to dust reddening, we must use wavelength ranges beyond the optical. The near-infrared (NIR) offers a possibility to extract information on spectral signatures that are not as obvious in traditional optical bands. Moreover, with the current and forthcoming generation of instrumentation focusing on the NIR, it is mandatory to explore possibilities within this wavelength range for nearby-Universe galaxies. However, although the NIR shows great potential, we are only beginning to understand it. Widely used techniques such as a full spectral fitting and line strength indices need to be tested on systems that are as close to simple stellar populations as possible, and the result from the techniques need to be compared to the yields from a traditional optical analysis. Methods. We present a NIR spectral survey of extragalactic globular clusters (GCs). The set was composed of 21 GCs from the Centaurus A galaxy that were obtained with SOAR/TripleSpec4, which covered the ∼1.0–2.4 μm range with a spectral resolution (R = λ/Δλ) of 3500. These spectra cover Hβ equivalent widths between 0.98 Å and 4.32 Å, and [MgFe]′ between 0.24 Å and 3.76 Å. Results. This set was ideal for performing absorption band measurements and a full spectral fitting, and it can be used for kinematic studies and age and abundance measurements. With this library, we expect to be able to probe the capabilities of NIR models, as well as to further improve stellar population estimates for the GCs around the Centaurus A galaxy.

Effect Of Mn2+On Physical And Spectroscopic Features Of Li2B4O7 And K2B4O7Glasses With Teo2

The present manuscript is to provide information about the preparation, and identification of the glassy nature, primary physical parameters, and structural studies of the effect of Mn2+ on K2B4O7 -TeO2 and Li2B4O7-TeO2 MnO[LTM] glasses. The glasses of thickness around 1 mm were obtained by the melt quenching method. These glasses are transparent enough to recognize them as glassy species but their amorphous nature was scientifically identified with peak-free XRD spectra. Several properties like density, molar volume, optical absorption, FTIR, Raman, and EPR spectra were measured and analysed, and discussed in detail. Density drastically decreased from 2.5176 gm/cc (LTM) to 2.3868 gm/cc (KTM) which is due to the presence of K2B4O7. Molar volume increased from 66.27 (LTM) to 115.61 (KTM) glass sample. From Optical absorption spectra, optical band gap energy decreased from 3.278 eV (LTM) to 2.888 eV (KTM) and the refractive index increased. FTIR and Raman studies combined reveal the existence of certain structural groups and the domination of a few borate modes. EPR studies confirmed the presence of Mn2+ ions