Absorption Bands Research Articles

A novel multifunctional Eu3+/Mn4+ co-doping double perovskite phosphor for applications in LEDs and optical thermometry

In recent years, phosphors have played important roles in solid-state lighting, plant growth lighting and optical temperature measurement. In this work, novel La3Mg2NbO9:Eu3+,Mn4+ phosphors were successfully prepared by the high temperature solid phase method and innovative multimode applications were investigated in optical thermometry, plant growth and White-LEDs. The crystal structure, surface morphology, photoluminescence, temperature sensing properties and luminescence mechanism of La3Mg2NbO9:Eu3+,Mn4+ phosphors were investigated in detail. Benefiting from the different responses of Eu3+ and Mn4+ ions to temperature, the La3Mg2NbO9:0.06Eu3+,0.0095Mn4+ sample shows excellent optical thermometry performance in the range of 303 ∼ 478 K. The maximum values of relative sensitivity (Sr) reach 2.7 % K-1 (@478 K) according to the fluorescence intensity ratio method and the maximum of Sr is 5.2 % K−1 (@428 K) based on the fluorescence lifetime method. Furthermore, the electrochromic spectrum of the red pc-LED prepared using La3Mg2NbO9:0.06Eu3+,0.005Mn4+ phosphor perfectly overlapped with the absorption bands of the photosensitive pigments for planting, and another white pc-LED prepared using La3Mg2NbO9:0.06Eu3+,0.0025Mn4+ phosphor emitted bright white light with a color rendering index of 89.8, color coordinate of (0.3468, 0.3557) and correlated color temperature of 4945 K. All the results demonstrate that the La3Mg2NbO9:Eu3+,Mn4+ phosphors are promising for the field of non-contact optical temperature thermometry, plant lighting lamps and pc-LED backlit displays.

Broadband sensitized near-infrared emission in Eu2+-Nd3+ co-doped BaAl2O4 as a potential spectral modulator for silicon solar cells.

The near-infrared (NIR) down-conversion process for broadband sensitization has been studied in Eu2+-Nd3+ co-doped BaAl2O4. This material has a broad absorption band of 200-480 nm and can convert photons in the visible region into NIR photons. The NIR emission at 1064 nm, attributed to the Nd3+:4F3/2 → 4I11/2 transition, matches the bandgap of Si, allowing Si solar cells to utilize the solar spectrum better. The energy transfer (ET) process between Eu2+ and Nd3+ was demonstrated using photoluminescence spectra and luminescence decay curves, and Eu2+ may transfer energy to Nd3+ through the cooperative energy transfer (CET) to achieve the down-conversion process. The energy transfer efficiency (ETE) and theoretical quantum efficiency (QE) were 68.61% and 156.34%, respectively, when 4mol% Nd3+ was introduced. The results indicate that BaAl2O4:Eu2+-Nd3+ can serve as a potential modulator of the solar spectrum and is expected to be applied to Si solar cells.

Impact of Carbon Dots on the Structural, Morphological, Magnetic, and Electrochemical Performance of Zn Ferrite for Energy Storage Applications

Magnetic core-shell Zn ferrite and carbon dots (C-dots) composite have been synthesized in this work using a simple coprecipitation and hydrothermal process, respectively. X-ray diffraction (XRD) patterns demonstrate an inverse spinel structure of Zn ferrites; the lattice parameter has decreased from 8.19Å to 8.10Å with C-dots. Scanning electron microscopy (SEM) images reveal rods-like structures for C-dots, and in the composite case, it is uniformly dispersed using low contrast consecutive C-dot layers to produce a core-shell structure. Zn ferrites are non-uniform in size, whereas C-dots and their composites are in uniform shape according to SEM images. The energy dispersive X-ray (EDX) study indicates that the substitution has been successful. For Zn ferrites, and composite, the Fourier transform infrared (FTIR) spectra shows that the absorption band of the tetrahedral site at 990 cm-1, and 870 cm-1, respectively. Different bonds in the infrared spectrum match specific function groups and bonding in various chemicals. The vibrating sample magnetometry (VSM) results indicates that the composite displays ferrimagnetic behavior. The specific capacity for composite has been found to be 2351 and 1790 F/g using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements, respectively. Higher electrochemical performance of the prepared composites may be helpful for energy storage systems.

Biopreparation of titanium dioxide nanoparticles mediated by Calendula officinalis flower extract for catalytic reduction of 4-nitrophenol and treatment of allergic conjunctivitis

This study investigates the an eco-friendly synthesis for the production of titanium dioxide nanoparticles (TiO2 NPs) by employing the water-soluble flower extract of Calendula officinalis as a natural reducing and stabilizing agent. The green produced TiO2 NPs/C. officinalis were characterized using different advanced analytical techniques, including FT-IR, FE-SEM, EDS-elemental mapping, XRD, ICP-OES and TEM. It represents the TiO2 NPs were found to be spherical in shape and well distributed without agglomeration. It also revealed the particle sizes were in the range of 30–50 nm. EDX represented the Ti atomic species along with C and O are seen to be well-dispersed in a homogeneous manner. The broad absorption band appeared at 3200–3450 cm−1 assigned to OH bond stretching belong to the adsorbed water over the titanium dioxide nanoparticles. Further, newly synthesized TiO2 NPs/C. officinalis are used as a nanocatalyst for the reduction of 4-nitrophenol (4-NP). A UV–Vis spectrophotometer is employed to track the effectiveness of the reduction process. Recyclability in 8 further degradation cycles is used to assess the sustainability of this catalyst, and the results show a steady and notable degradation activity. After a week of daily treatment, the allergic conjunctivitis clinical scores in Dunkin-Hartley guinea pigs were evaluated. The guinea pigs were sensitized with intraperitoneal ovalbumin and then subjected to topical conjunctival challenge. Different doses of TiO2 NPs/C. officinalis (20 and 100 µg/kg), prednisolone (30 mg/kg), chlorpheniramine (10 mg/kg), or PBS (10 mL/kg) were administered. The levels of serum Immunoglobulins were measured by ELISA. It was observed that the levels of ovalbumin-specific IgE notably decreased. Notably, the treatment with TiO2 NPs/C. officinalis at both doses led to a notably lower clinical score for allergic conjunctivitis. Furthermore, the TiO2 NPs/C. officinalis-treated guinea pigs conjunctival tissue showed mild mononuclear infiltration compared with the intense conjunctival tissue inflammatory infiltration observed in the PBS-treated group. These data suggest that TiO2 NPs/C. officinalis may have clinical efficacy in alleviating allergic conjunctivitis.

Zinc-doped hexaferrite exhibits altered physical properties in the presence of both Dy and Zn ions

The nanosized M-type hexaferrites SrFe11.5Zn0.5O19, Sr0.95Dy0.05Fe12O19, and Sr0.95Dy0.05Fe11.5Zn0.5O19 were produced by auto combustion utilizing citric acid. The impacts of substituting Zn2+ as well as Dy3+ ions upon the structural, electrical, magnetic, and optical properties of SrFe11.5Zn0.5O19, Sr0.95Dy0.05Fe12O19 and Sr0.95Dy0.05Fe11.5Zn0.5O19 nanoferrites have been studied using XRD, FTIR, UV–Visible, FESEM, VSM, and LCR meter. The formation of a single-phase lattice was confirmed by the XRD analyses. For the investigated samples, the crystallite size rose from 36 nm for SrFe11.5Zn0.5O19 to 37 and 33 nm, for Sr0.95Dy0.05Fe12O19, and Sr0.95Dy0.05Fe11.5Zn0.5O19 respectively. In FTIR spectra, a couple of absorption bands have been seen. The prepared samples possess a strong tendency to clump together into large masses, according to FSEM. The samples’ band gap values vary from 1.8 to 2.4 eV. Additionally, the dielectric parameters based on a Maxwell–Wagner two-layer approach have also been described. The results reveal that the dielectric constant (ε’) as well as dielectric loss (ε’’) decrease with increasing applied field frequency, whereas the AC conductivity (σac) increases. The VSM results show that all the investigated materials are referred to as hard magnetic materials.

Impact of Gd-Substitution on Structural, Dielectric, Spectroscopic, Raman, and Photo luminance Properties of Ba0.4Sr0.6Co2Fe16O27 Ceramics

This paper represents a detailed study of Gd3+ substitutions on Structural, Dielectric, Spectroscopic, Raman, and Photo luminance Properties of Ba0.4Sr0.6Co2Fe16O27 magnetic oxides were prepared using the sol-gel auto combustion method. All of these specimens were sintered at 1100 ºC for five hours. X-ray diffraction analysis (XRD) confirmed the single-phase detection and structural analysis. The lattice parameters a and c show the insignificant behavior 5.893-5.933 Å, and 32.049-32.476 Å with the concentration of gadolinium ions. The crystallite size ranged from 25 to 30 nm, demonstrating a growing tendency as Gd-substitution was enhanced. The discrepancy in the ionic radii of iron (Fe3+) and substituent elements (Gd3+) is the cause of the variation in cell volume and lattice constants. FTIR spectroscopy confirmed the presence of absorption bands (590 and 3000 cm-1) for prepared BaSr-based W-type hexa-ferrites. The vibrational bands of metal oxide ions are responsible for the 590 and 685 cm-1 peaks. The Raman spectrum showed six discrete, brittle peaks: 320, 440, 620, 690, 1300, and 1600 of synthesized nanomaterials—the dielectric constant and dielectric loss increase by substituting the Gd3+ ion. The dielectric parameters and dielectric loss at higher frequencies suggest that the prepared material may be excellent for switching, sensing, and high-frequency applications.

Molecules in Cool Stars: The A2Π − X2Σ+ and the B2Σ+ − X2Σ+ Band Systems of CaCl

Cool red giant stars exhibit absorption bands of calcium monochloride (CaCl) in the optical region. In this work, the bands of CaCl corresponding to the A2Π − X2Σ+ transition with v′≤ 4 and v″ ≤ 4, and B2Σ+ − X2Σ+ transition with v′≤ 2 and v″ ≤ 2 are rotationally analyzed with PGOPHER, a multipurpose program for simulating and fitting molecular spectra. All bands were analyzed using high-resolution absorption spectra collected at the National Solar Observatory in 1985, calibrated with atomic lines from a high-resolution emission spectrum obtained in a separate hollow cathode experiment. The results are compared with previous laser-induced fluorescence measurements. Overall, the accuracy of spectroscopic constants for the A2Π and B2Σ+ states is improved. Scaled transition dipole moment calculations were used to obtain line strengths. Line lists are provided with Einstein A coefficients and oscillator strengths, which can be used to determine CaCl stellar abundances. Additionally, isotope splittings allowed us to estimate band origins for the 40Ca37Cl isotopologue based on band-head positions.

Exploring the role of neutral ligands in modulating the photoluminescence of samarium complexes with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione.

Four eight-coordinated luminescent samarium complexes of type [Sm(hfpd)3L2] and [Sm(hfpd)3L'] [where hfpd = 1,1,1,5,5,5-Hexafluoro-2,4-pentanedione L = tri-octyl-phosphine oxide (TOPO) and L' = 1,10-phenanthroline (phen), neocuproine (neoc) and bathocuproine (bathoc) were synthesized via a stoichiometrically controlled approach. This allows for precise control over the stoichiometry of the complexes, leading to reproducible properties. This investigation focuses on understanding the impact of secondary ligands on the luminescent properties of these complexes. Infrared (IR) spectra provided information about the molecular structures, whereas 1H and 13C nuclear magnetic resonance (NMR) spectra confirmed these structural details along with the coordination of ligands to trivalent Sm ion. The UV-vis spectra revealed the molar absorption coefficient and absorption bands associated with the hfpd ligand and photoluminescence (PL) spectroscopy demonstrated intense orange-red emission (648 nm relative to 4G5/2 → 6H9/2) from the complexes. The Commission Internationale de l'Éclairage (CIE) triangles indicated that the complexes emitted warm orange red light with color coordinates (x, y) ranging from (0.62, 0.36) to (0.40, 0.27). The investigation of the band gap as well as color parameters confirms the utility of these complexes in displays and LEDs.

Synthesis, structure and photoluminescent properties of far-red Y3Ga5O12:Cr3+ phosphors

Far-red (FR) photosensitive pigment (PFR) is vital for plant photomorphogenesis. Phosphor-converted (pc) LEDs are the next-generation FR light devices. How to obtain FR-emitting phosphors with a good quantum efficiency, suitable photoluminescence and high thermal stability is still difficult. Herein, we optimize the Y3Ga5O12:Cr3+ FR phosphor, which has an emission peak at 711 nm and a full width at half maximum of 74 nm, closing to the PFR absorption band. By adopting the solid-state sintering technology, the internal quantum efficiency reaches 85.5 %, more than 1.5 times higher than that reported by the liquid reaction (55 %). Furthermore, the external quantum efficiency reaches as high as 33.1 %, indicating the promising application in FR-LEDs.

Upconversion luminescence resonance energy transfer (LRET)-based dual-channel biosensor for rapid detection of coronavirus

Researchers recently have been working on a sensitive, accurate, and easily accessible way to detect coronaviruses. Traditional polymerase chain reaction detection technology has high sensitivity and specificity, but there are some problems, such as a complicated detection process, false negatives caused by gene mutation of coronavirus, and easy infection of operators. Antigen detection, which does not require gene amplification and other preprocessing, can be operated by non-medical staff for rapid detection. However, its detection sensitivity requires high reliability and further improvement. Accordingly, a biosensor based on luminescent resonance energy transfer (LRET) from upconversion nanoparticles (UCNPs) to gold nanoparticles (AuNPs) and antigen detection has been developed for rapid and sensitive detection of N protein of SARS-CoV-2. By adjusting the reaction conditions, LRET can be realized by making the spectral overlap between the luminescence of UCNPs and the absorption band of AuNPs, which can effectively avoid the generation of biological background light and the interference of other signals in the test process. In addition, the thiol-ene click reaction was used to link Thiol-PEG-COOH to UCNPs to improve its biocompatibility. The antigen recognition of the coronavirus based on the as-proposed detection method can be further realized on the test paper. A linear response is obtained ranging from 10 ng mL−1 to 1280 ng mL−1, and the detection limit is around 0.80 ng mL−1 with a detection time of around 10 minutes, which has a wide range of potential future. This fast and sensitive biosensor for coronavirus detection can be further reflected in the test paper and is promising for practical applications.

Spectro-photometry of Phobos simulants: I. Detectability of hydrated minerals and organic bands

Previous Mars Reconnaissance Orbiter and Mars Express observations of Phobos and Deimos, the moons of Mars, have improved our understanding of these small bodies. However, their formation and composition remain poorly constrained. Physical and spectral properties suggest that Phobos may be a weakly thermal-altered captured asteroid but the dynamical properties of the martian system suggest a formation by giant collision similar to the Earth moon. In 2027, the JAXA’s MMX mission aims to address these outstanding questions.We undertook measurements with a new simulant called OPPS (Observatory of Paris Phobos Simulant) which closely matches Phobos reflectance spectra from the visible to the mid-infrared wavelength range. The simulant was synthesized using a mixture of olivine, saponite, anthracite, and coal.Since observation geometry strongly influences the photometry and spectra of the light reflected from planetary surfaces, we evaluated the parameters obtained by modeling the phase curves – obtained through laboratory measurements – of two different Phobos simulants (UTPS-TB and OPPS) using Hapke IMSA model. Our results show that the photometric properties of Phobos simulants are not fully consistent with those of carbonaceous chondrites and martian meteorites. We also investigated the detection of volatiles/organic compounds and hydrated minerals, as the presence of such components is expected on Phobos in the hypothesis of a captured primitive asteroid. To investigate their detectability, we examined the variability of the 3.28μm and 3.42μm absorption bands related to aliphatic/aromatic carbon (as a proxy of organic material), as well as the 2.7μm O-H feature in a Phobos laboratory spectroscopic simulant. The results indicate that a significant amount of organic compounds is required for the detection of C-H bands at 3.4μm. The bands at 3.28 and 3.42μm are faint (less than 2%) when ∼3 wt% of organic compounds are present in the simulant and are likely undetectable by the MIRS spectrometer onboard the MMX mission. When the concentration of aliphatic and aromatic compounds is increased to 6 wt%, a positive detection starts to become more plausible using remote sensing infrared spectroscopy. In contrast, the 2.7μm absorption band, due to hydrated minerals, is much deeper and easier to detect than C-H organic features at the same concentration levels. The feature is still clearly detectable even when the simulant contains only 3 vol.% of phyllosilicates, corresponding to 0.7 wt% OH groups.Posing limits on detectability of some possible key components of Phobos surface will be pivotal to prepare and interpret future observations of the MIRS spectrometer as well as TENGOO and OROCHI cameras onboard MMX mission.

Tb3+ doped silicoborate glass scintillator for high resolution synchrotron X-rays imaging application

This research aims to develop a combination of SiO2 and B2O3 glass former (called, silicoborate glass) to be used as a scintillation material for digital radiography application. The silicoborate glass doped with different concentration of Tb2O3, xTb2O3–7.5Gd2O3–40Na2O–5SiO2– (47.5-x)B2O3, where x = 0, 1, 2, and 3 mol% (xTb:7.5Gd) were prepared by melting and then rapid quenching in graphite mold. The density of the prepared glasses was high with Tb2O3 concentration, indicating that the glass became denser and could strongly interact with X-rays. The molar volume increased with Tb2O3 concentration, suggesting the increase of Non-Bridging Oxygen (NBOs) in glass matrix. The xTb:7.5Gd glasses absorbed photons in visible and near-infrared regions and was observed that the absorption bands increased with Tb2O3 concentration, which was the result of the 4f6-4f6 transitions behavior of Tb3+ ions. The photoluminescence and radioluminescence results revealed the distinct emission occurring at 544 nm (5D4→7F5). The photoluminescence quantum yield (PLQY) of glass had the maximum efficiency at 30.85%. The luminescence peak area under X-rays excitation glass was maximum at 109% of BGO crystal. CIE 1931 chromaticity of the xTb:7.5Gd glasses showed the color coordinates in yellowish-green area. The decay time of the xTb:7.5Gd glasses were in the millisecond range for different excitations. The probability of energy transfer was investigated between Gd3+ and Tb3+ ions in glass and may occur mainly between the 6P7/2 level of Gd3+ and 5H7 level of Tb3+. The X-rays imaging using the developed glass as a scintillator was performed by Synchrotron X-rays and the spatial resolution 6 lp/mm was achieved. These results demonstrate that the 3 mol% of Tb2O3 doped silicoborate glass can be used as a scintillator and can be applied for a high-resolution Synchrotron X-rays imaging system.

Exploring structural and optical properties of Cu-doped and Fe-doped sodium borate glasses

This study investigated the structural and optical properties of Cu-doped and Fe-doped sodium borate glasses. X-ray diffraction (XRD) patterns confirmed that both samples were amorphous, with no sharp peaks. However, differences in the width and center of the high-intensity humps suggested variations in atomic packing and field strength between the two samples. Fourier transform infrared (FTIR) spectra showed wider vibrational modes and stronger absorption in the Fe-doped sample, confirming its higher atomic packing and field strength. Luminescence spectra indicated that the Cu-doped sample had a higher ratio of Cu2+:Cu3+ than the Fe-doped sample of Fe2+:Fe3+, resulting in greater UV-visible region absorption. Optical parameters such as absorbance, transmittance, and reflectance supported these findings, with the Fe-doped sample exhibiting higher absorbance band edges. Quality factor (Q.F.) analysis revealed that the Fe-doped sample had a larger Q.F. than the Cu-doped sample, indicating lower energy losses. Furthermore, the optical conductivity of both samples increased with photon energy, with the Cu-doped sample dominating in all energy regions. Finally, both samples exhibited high effective atomic numbers, suggesting potential applications in radiation shielding, with the Cu-doped sample having a wider radiation shielding window. Finally, the findings unique structural and optical properties suggests the Cu-doped and Fe-doped sodium borate glasses to a lot of potential applications in various fields including radiation shielding, optics, electronics, and energy storage.

The Study of Lead-Free CH3NH3GeX3 (X=F, Cl, Br, I and At) for Optoelectronic Applications Using First-Principle

Organometallic perovskites, with their exceptional electric, magnetic, piezoelectric, and optical properties, are prominent in materials science research. The environmental and health concerns associated with lead-based perovskites have spurred the search for lead-free alternatives, such as methylammonium germanium halides. This study investigates the optical and electronic properties of organometallic perovskite materials, focusing on methylammonium germanium halides (CH3NH3GeX3, where X = F, Cl, Br, I, At). Using computational methods, the analysed properties including band gap energies, dielectric constants, extinction coefficients, optical conductivity, absorption coefficients, reflectivity, refractive indices, and lattice constants. The results show a decreasing trend in band gap energies from 3.987 eV (CH3NH3GeF3) to 0.821 eV (CH3NH3GeAt3), indicating weaker bonding interactions with larger halide ions. Lattice constants increase from 4.981 Å (CH3NH3GeF3) to 6.068 Å (CH3NH3GeAt3), reflecting the larger ionic radii of the heavier halides. CH3NH3GeI3 displayed the highest dielectric constant, demonstrating a strong response to external electric fields. Extinction coefficients were significant within the 0 to 10 eV frequency range, with CH3NH3GeI3 showing the highest values. Optical conductivity peaked in CH3NH3GeI3, suggesting its potential for photovoltaic and light-emitting applications. The absorption coefficients indicated strong visible range absorption for CH3NH3GeI3. Reflectivity analysis revealed that CH3NH3GeF3 and CH3NH3GeCl3 had higher static reflectivity, suitable for applications requiring minimal reflection, whereas CH3NH3GeI3 exhibited minimal reflection, beneficial for high-efficiency photovoltaic cells. The refractive index analysis showed that CH3NH3GeI3 had the highest static refractive index, indicating significant optical density and light-slowing capabilities. These findings highlight the relationship between halide substitution and the optical properties of organometallic perovskite materials, providing insights for tailored technological applications.

PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBON FROM DATE PALM (Phoenix dactylifera) SEEDS

In this study, agricultural waste (date seeds) were used to produce activated carbon in an oxygenated environment. The produced activated carbon was characterised. The HRSEM showed mesoporous structural morphology, which exhibited a surface area of 54.53 m2/g, pore size of 10.34 nm and pore volume of 0.1256 cc/g. The EDX spectrum revealed the presence of C and O as the major elemental compositions in the activated carbon. The FTIR spectrum indicated the presence of OH-, C=C, C=O and C-H at absorption bands of 3400, 2900, 1650, and 1300 cm-1, respectively. The diffractogram of the activated carbon revealed graphitic carbon 2 peaks of 22o and 43o which are related to (002) and (100) plane, respectively. The conversion of agricultural waste to activated carbon possessing these unique properties could serve as a promising and low-cost adsorbent for the removal of toxic pollutants from industrial wastewater.

In Ukrainian

Blood loss is one of the main causes of death, especially in war and natural disasters. At the beginning of the full-scale Russian-Ukrainian war we established the laboratory and later the industrial production of a powdered topical hemostatic composition based on nanosilica which is intended for providing first pre-medical aid. The composition contains nanosized silica A-300 and sodium alginate as two active ingredients in a mass ratio of 4:1. The aim of the work was to develop the optimal technological process for the production of a hemostatic composition and carry out physico-chemical and medical-biological studies of semi-finished products and the final product. Bulk density measurements, optical microscopy, IR spectroscopy method and microbiological research were used to study the initial materials, intermediate products as well as the final product. The effectiveness of the hemostatic effect of the composition was checked on the model of parenchymal bleeding from the liver of a rat, using the time to stop bleeding (min) as a criterion. As a result of the research, a two-stage method of manufacturing the composition is proposed: at the first stage, certain parts of the initial materials are treated in a ball mill, obtaining the semi-finished product "A-300/sodium alginate"; at the second stage, this semi-finished product is mixed with nanosilica and sodium alginate, obtaining the final product. It is shown that the bulk density serves as a useful technological parameter to control of which helps to produce a structurally homogeneous final product. In the IR spectra of the semi-finished product and the finished product, only the absorption bands of silica and sodium alginate are observed, that is, foreign substances are not formed during technological process. The microbiological purity of the composition meets the pharmacopoeial requirements for drugs of this category. An experimental study of the topical hemostatic effect of the composition revealed its significant advantage compared to the inorganic hemostatic substance kaolin, which acts according to a similar adsorption mechanism.

Green Synthesis of Silver Nanoparticles with Extracts from Kalanchoe fedtschenkoi: Characterization and Bioactivities.

In this work, the hexane, chloroform, and methanol extracts from Kalanchoe fedtschenkoi were utilized to green-synthesize silver nanoparticles (Kf1-, Kf2-, and Kf3-AgNPs). The Kf1-, Kf2-, and Kf3-AgNPs were characterized by spectroscopy and microscopy techniques. The antibacterial activity of AgNPs was studied against bacteria strains, utilizing the microdilution assay. The DPPH and H2O2 assays were considered to assess the antioxidant activity of AgNPs. The results revealed that Kf1-, Kf2-, and Kf3-AgNPs exhibit an average diameter of 39.9, 111, and 42 nm, respectively. The calculated ζ-potential of Kf1-, Kf2-, and Kf3-AgNPs were -20.5, -10.6, and -7.9 mV, respectively. The UV-vis analysis of the three samples demonstrated characteristic absorption bands within the range of 350-450 nm, which confirmed the formation of AgNPs. The FTIR analysis of AgNPs exhibited a series of bands from 3500 to 750 cm-1, related to the presence of extracts on their surfaces. SEM observations unveiled that Kf1- and Kf2-AgNPs adopted structural arrangements related to nano-popcorns and nanoflowers, whereas Kf3-AgNPs were spherical in shape. It was determined that treatment with Kf1-, Kf2-, and Kf3-AgNPs was demonstrated to inhibit the growth of E. coli, S. aureus, and P. aeruginosa in a dose-dependent manner (50-300 μg/mL). Within the same range, treatment with Kf1-, Kf2-, and Kf3-AgNPs decreased the generation of DPPH (IC50 57.02-2.09 μg/mL) and H2O2 (IC50 3.15-3.45 μg/mL) radicals. This study highlights the importance of using inorganic nanomaterials to improve the biological performance of plant extracts as an efficient nanotechnological approach.

Synthesis, Characterization and Anticancer Activity of Chitosan Schiff Base / PEG Blend Doped with Gold and Silver Nanoparticles in Treatment of Breast Cancer Cell Line MCF-7

In the present study, chitosan Schiff base has been prepared from chitosan reaction with the para chloro benzaldehyde. The AuNPs and AgNPs were manufacture by extract of onion peels as a reducing agent. The AuNPs and AgNPs that have been synthesized were characterized through UV-vis spectroscopy the XRD analyses and SEM microscopy. The polymer blends of the chitosan / PEG has been prepared through using the approach of solution casting. Chitosan Schiff base / PEG Au and Ag nano-composites were synthesized nano composites and polymer blends have been characterized by FTIR which confirm the formation of Schiff base by revealing a new band of absorption at 1693 cm-1 as a result of the (C=N) imine group. FESEM, DSC and TGA confirms the thermal stability of the prepared polymer blends and nanocomposites, nano composites have shown good results in inhibiting breast cancer cell line MCF-7, IC50 of nanocomposite = 19.44 µg / mL.

Structural and Optical Characterization of Porous NiV2O6 Films Synthesized by Nebulizer Spray Pyrolysis for Photodetector Applications.

NiV2O6 thin films were grown on glass slides with varying thicknesses using nebulizer spray pyrolysis. The impact of thickness on the thin films' optical, structural, morphological, and electrical characteristics was systematically investigated. X-ray diffraction and micro-Raman analysis confirmed the formation of the triclinic NiV2O6 system. Surface morphology and roughness variations in the as-deposited NiV2O6 films were studied using scanning electron microscopy (SEM) and a profilometer. Optical properties, including optical band gap (Eg), extinction coefficient (k), absorption coefficient (α), and refractive index (n), were determined through optical reflectance and transmittance measurements. The optical energy gap of the as-deposited NiV2O6 films decreased from 2.02 eV to 1.58 eV with increased layer thickness. Furthermore, the photo-detectivity of the films demonstrated an enhancement corresponding to the prolonged spray time. The sensitivity values obtained for visible irradiation were 328, 511, and 433 for samples S1, S2, and S3, respectively. The obtained results can be imputed to the specific porous microstructure.

The Effect of Conjugated Nitrile Structures as Acceptor Moieties on the Photovoltaic Properties of Dye-Sensitized Solar Cells: DFT and TD-DFT Investigation.

A major challenge in improving the overall efficiency of dye-sensitized solar cells is improving the optoelectronic properties of small molecule acceptors. This work primarily investigated the effects of conjugation in nitriles incorporated as acceptor moieties into a newly designed series of D-A-A dyes. Density functional theory was employed to specifically study how single-double and single-triple conjugation in nitriles alters the optical and electronic properties of these dyes. The Cy-4c dye with a highly conjugated nitrile unit attained the smallest band gap (1.80 eV), even smaller than that of the strong cyanacrylic anchor group (2.07 eV). The dyes lacking conjugation in nitrile groups did not contribute to the LUMO, while LUMOs extended from donors to conjugated nitrile components, facilitating intramolecular charge transfer and causing a strong bind to the film surface. Density of state analysis revealed a considerable impact of conjugated nitrile on the electronic properties of dyes through an effective contribution in the LUMO, exceeding the role of the well-known strong 2,1,3-benzothiadiazole acceptor unit. The excited state properties and the absorption spectra were investigated using time-dependent density functional theory (TD-DFT). Conjugation in the nitrile unit caused the absorption band to broaden, strengthen, and shift toward the near-infrared region. The proposed dyes also showed optimum photovoltaic properties; all dyes possess high light-harvesting efficiency (LHE) values, specifically 96% for the dyes Cy-3b and Cy-4c, which had the most conjugated nitrile moieties. The dyes with higher degrees of conjugation had longer excitation lifetime values, which promote charge transfer by causing steady charge recombination at the interface. These findings may provide new insights into the structure of conjugated nitriles and their function as acceptor moieties in DSSCS, which may lead to the development of extremely effective photosensitizers for solar cells.