Thestructuralandopticalproperties,aswellasdielectriccharacteristicsatvariousfrequencies(0.1Hz —20MHz)andtemperatures,T(300–400K),ofhydrothermallysynthesizedSnO2nanoparticles, Cu/SnO2,andFe/SnO2compositeshavebeeninvestigated.Thecrystalstructureismostlyformedofa tetragonal SnO2phase,withasecondphaseofmonoclinicCuOorrhombohedralFe2O3detectedin Cu/SnO2,andFe/SnO2composites,respectively.Thedirectopticalbandgap,residualdielectric constant,anddensityofchargecarriersareincreased,whileacconductivity(σac)anddielectric constantdecreasedinCu/SnO2andFe/SnO2.Thevalueofσacwasdecreasedwhiletheelectric Q-factorwasincreasedbyincreasingT.SnO2obeyedthehole-conductionmechanismfor400 T(K) 300,whileCu/SnO2andFe/SnO2obeyedtheelectronic-conductionmechanismfor400 T (K)>300.Thebindingenergyisindependentof TforSnO2,whereasitincreaseswithrisingTfor Cu/SnO2andFe/SnO2composites.F-factorandelectronicpolarizabilityareimprovedbyariseof T for SnO2andCu/SnO2meanwhilearedecreasedforFe/SnO2.Theelectricalimpedanceofthegrains andtheirboundariesaswellasequivalentcapacitanceareincreasedbyincreasingTandhavehigher valuesforFe/SnO2atT>300K.TheobtainedresultsrecommendthesynthesizedCu/SnO2and Fe/SnO2compositestobeusedascatalystsforwaterpurification,anodesforlithiumbatteries, supercapacitors, andsolarcellapplicationsamongstothers.

The effect of annealing temperature (Ta= 200, 250, and 300 °C) on the structural properties, ac conductivity, and complex dielectric constants ( ϵ and ϵ ) of indium-doped tin oxide (ITO) thin films (~ 90 nm thick)/0.5 mm boro-float substrates (BFS) synthesized by radio frequency (RF) sputtering is investigated. The X-ray diffraction (XRD) examination demon strated that indium was successfully substituted with tin atoms to form ITO films and the crystallite size for the cubic phase, as well as particle size, were impacted by Ta. The real part of complex dielectric constants ( ) was significantly reduced for all ITO/BFS from the range of 2.7 × 104–5.1 × 104 to 5.3–19 as the frequency (f) was increased to 0.25 Hz, while it remained constant for further increases in f. The value of ϵ ϵ for the as-prepared ITO/BFS was increased as Ta increased up to 250 °C, then was decreased at Ta=300 °C. A similar finding was detected for the loss factor with no obser vation of any relaxation peaks. The Q-factor was increased for all ITO/BFS as f increased to 100 Hz and then was reduced with increasing f up to 20 MHz, while steadily increasing with Ta. The deduced frequency exponent is greater than 0.5 for the ITO/BFS, indicating their electronic conduction nature. The density of the localized states and hopping frequency of the ITO/BFS were increased by annealing at 200 °C, meanwhile was decreased for Ta = 300 °C. The binding energy was decreased from 0.647 eV for the as-prepared ITO/BFS to 0.518 eV by annealing at 200 °C, meanwhile was increased to 0.74 and 0.863 eV for Ta equals 250, and 300 °C, respectively. The Cole-Cole plots revealed a single semicircular arc for all films, and their corresponding equivalent circuit was analyzed. The equivalent bulk resistance was gradually decreased by annealing in the range of 200–300 °C, whereas the equivalent capacitance was increased. The resistance of grains and resistance of grain boundaries of the as-prepared ITO/BFS was gradually decreased by increasing Ta to 250 °C, while it was increased for Ta = 300 °C. These outcomes recommended the RF sputtered ITO/BFS for high-frequency devices, integrated circuits, and supercapacitors.

Incorporation of different ratios (0, 0.25, 0.5, 0.75, and 1 wt%) of graphene nano plates (GNPs) or multi-wall carbon nanotubes (MWCNTs) within polyvinylchlo ride (PVC) via casting method has been examined to improve their structural and linear/nonlinear optical performance. The structural study was carried out using an AFM, FTIR, FE-SEM, and XRD. Different surface and intermolecular structural modifications are induced depending on the dispersed nano-filler type in the PVC matrix. FTIR analysis revealed the disappearance of the –OH and C–H bands accompanied by the appearance of new bands related to the C=O and C–O stretching modes with different intensities for PVC/GNPs and PVC/MWCNTs nanocomposites. The linear and nonlinear optical measurements were performed using a double-beam spectrophotometer and the optoelectronic parameters were deduced from the transmission and reflectance spectra. Optical parameters and constants such as the direct and indirect energy gap, single oscillator energy, dis persion energy, ratio of carrier concentration to its effective mass, lattice and infi nite frequency dielectric constant, the linear/nonlinear refractive index, and the third-order susceptibility, based on the types and concentrations of the dispersed GNPs or MWCNTs in the PVC matrix are discussed. The solar skin protection factor (SSPF) of PVC/GNPs nanocomposite with 1 wt% of GNPs increased from 0.7 to 13.5%, while the same MWCNTs contents increased SSPF factor to 11.9%. The calculated optical parameters were found to be GNPs and/or MWCNTs wt% dependent due to their different individual properties and geometry. The present work revealed a guide for tuning the PVC optical properties using both types of nano-filler for usage in flexible optoelectronic applications.

The anodization of pure aluminum (Al) thin films of 0.5 μm thick on Titanium nitride/Silicon (TiN/Si) substrate in the lithium-based electrolytes at 2.5 V was performed to form porous and mesh morphologies of alumina–lithium composites. The electrochemical analysis through the anodization process and the morphology using a scanning electron microscope of the obtained porous alumina–lithium composites were discussed. The anodization of Al/TiN/Si films in lithium-based elec trolytes resulted in the synthesis of ultra-thin walls porous anodic alumina (PAA) with incorporated lithium ions confirmed by Raman spectroscopy. The impedance spectroscopy was performed to study the influence of incorporated lithium ions into the PAA matrix on its electronic properties. The impedance spectroscopy analysis revealed an improvement in the electri cal impedance of the formed PAA compared to the insulated alumina. In addition, its impedance data show a capacitance behavior with a low series resistance value which can be exploited for high-performance battery applications.

(Nb0.5Si0.5)xTi1 xO2 nanocomposites (x =0, 0.025, 0.05, and 0.1) were produced by the easy and versatile mechanical milling technique. Structural parameters, optical absorbance, surface area, and photocatalytic per formance towards methylene blue (MB) under ultraviolet–visible (UV–Vis) radiation were investigated. The structural analysis revealed the formation of rutile and brookite phases, confirming the good incorporation of Nb0.5Si0.5 inside the TiO2 lattice. The crystallite size of formed phases was slightly affected by the dopant and its average value is in the range of 5–7 nm. The morphology of composites is composed of spherical-like nano particles with an average particle size range of 10–22 nm, and the highest surface area (19.19 m2/g) was reached for (Nb0.5Si0.5)0.025Ti0.075O2. The FTIR, Raman, and XPS analyses indicated the formation of numerous Ti–O–Ti, Si–O–Ti, and Si–O–Si bonds and emphasized the formation of rutile and brookite phases. The optical band gap obeyed the direct transition mechanism, and its average values were 3.4, 3.82, 3.7, and 3.5 eV for x =0, 0.025, 0.05, and 0.1, respectively. The photodegradation efficiency (η) of TiO2 towards MB was enhanced by Nb0.5Si0.5 doping, catalyst dosage, pH value, and irradiation time. The maximum value of η towards MB was 76.6 % and was attained after UV–Vis irradiation for 140 min in the presence of 1 g of (Nb0.5Si0.5)0.025Ti0.075O2 catalyst per 1 L MB, with the highest rate kinetic constant of 1.02 ×10 2 min 1. The value of η increased up to 94.34 % by adjusting the pH to 10. The optimum catalyst dosage for the MB photodegradation (96.4 %) is 2 g/L. Moreover, the recycling experiments demonstrated adequate reusability for the investigated catalyst. Furthermore, the adsorbed dye on the surface of the catalyst has been investigated and the degraded products were analyzed using the GC-MS technique, with a postulated mechanism of degradation. Therefore, the prepared (Nb0.5Si0.5)xTi1 xO2 nanocomposites are suitable for the degradation of various toxic dyes and may apply to various technologies required for modulated optical band gaps such as UV photodetector.

Fano resonance is a sharp and asymmetric spectral feature that can be used for refractive index sensing. In this paper, we propose a Fano resonance sensor based on the coupling between a nanoring resonator and a metal-insulator-metal (MIM) waveguide. The nanoring resonator is fabricated in the middle of the MIM waveguide, and the two structures are coupled with high-field confinement. The transmission spectrum of the coupled structure shows a Fano resonance, which is sensitive to the refractive index of the surrounding medium. The sensitivity of the sensor is estimated to be 1700 nm/RIU, which is comparable to the sensitivities of other Fano resonance sensors. In addition, the designed sensor achieves the first-ever FOM and Q factor values of 4300.25 RIU-1 and 4310, respectively, for plasmonic MIM sensors. The proposed sensor is simple to fabricate and can be used for a wide range of refractive index sensing applications.
 

The structural parameters, optical properties, and dielectric constants at a frequency (f) range of 0.1–20 MHz, and temperature (T) range of 300–400 K of hydrothermally synthesized M/SnO2 nanocomposites (for simplicity M denotes oxides of Al, Ni, or Mn) were compared. Rietveld refined X-ray powder diffraction (XRD) analysis demonstrated the formation of hexagonal, cubic, or spinel crystal structures of Al2O3, NiO, or Mn3O4 phases, respectively, besides the tetragonal rutile crystal structure of SnO2. The impact of Al addition on the optical band gap of SnO2 is negligible while it decreased or increased by incorporation of Ni or Mn, respectively. The residual lattice dielectric constant of SnO2 was increased, while the real part of the dielectric constant and the ac con ductivity of SnO2 were decreased by M incorporation. The dielectric parameters are remarkably affected by selected M, T, and f values and their changes agree with the Maxwell-Wagner model. The Q-factor of SnO2 was increased by M addition while decreased with increasing T. The Ni/SnO2 obeys the hole conduction at T ≤330 K, while Mn/SnO2 and Ni/SnO2 obey the electronic conduction at T >330 K. The binding energy is independent of the chosen T for SnO2, whereas it sharply increases for Ni/SnO2 and slightly decreases for Al/SnO2 and Mn/SnO2. The F-factor of SnO2 was slightly decreased by M addition, but it was increased with T for SnO2, Al/SnO2, and Mn/SnO2 while was decreased for Ni/SnO2. The Cole-Cole plots for M/SnO2 composites were analyzed, and the components of the equivalent circuit were determined. The electrical impedance, resistance of grains, resistance of grain boundaries, and equivalent resistance of SnO2 were increased by M incorporation, whereas equivalent capacitance was decreased. The findings recommend the SnO2-based nanocomposites for applications in opto electronics, lithium batteries, supercapacitors, and solar cell devices.

Two novel thiosemicarbazone linked with 1,3,4-thiadiazole ligands were synthesized through the condensation reaction of the acetyl group at position 5 of 1,3,4-thiadiazole derivatives with thiosemicarbazide in acidic ethanol solution in addition to their Co(II)-complexes. The divalent cobalt complexes of both ligands have been synthesized through the reaction of cobalt acetate with each ligand leading to the formation of the two complexes [(LH)Co(OAc)]0.5H2O and [(LCl)Co(OAc) (H2O)2]; where LH and LCl are 1,3,4-thiadiazolethiosemicarbazone ligands. The two complexes have been proved to have tetrahedral and octahedral geometry from the results of UVeVis spectra and magnetic moment. Analysis of the IR spectra of both ligands and complexes ascertained that the ligands behaved as monobasic tridentate coordinating to the metal ion center through azomethine-nitrogen atoms and thiadiazole ring in addition to deprotonated SH group. The synthesized ligands and their complexes were also investigated as inhibitors for the corrosion of carbon steel in 1.0 M HCl using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscopy techniques. The obtained results revealed that the inhibition efficiencies of the tested derivatives were found to depend on the concentrations and structures of such derivatives, and were decreased with raising temperature. At the same inhibitors concentration, the inhibition efficiencies are slightly increased in the order: LH > LCl > LH-Co > LCl-Co. The results derived from all applied techniques are harmonious with each other.

The divalent copper, cobalt, nickel and cadmium in addition to the trivalent iron complexes of the ligand named (E)-1-((4,6- dimethylpyrimidin-2-ylimino)methyl)naphthalen-2-ol were synthesized by the reaction of the ligand with diferent metal chlorides. The Structures and geometry of the metal chelates have been successfully deduced applying various analytical and spectroscopic tools such as elemental analysis, molar conductance, TGA, magnetic moment measurements, IR, 1 H-NMR, EI-mass and UV–Vis spectral studies. The X-ray single crystal structure of the ligand has been also discussed. Spectral studies and analytical results supported the monobasic bidentate behavior of the ligand connecting the metal ion centers via deprotonated phenolic OH and imine nitrogen. In the case of Cu(II) complex, the pyrimidine nitrogen took part in coordination to the Cu center. The results ensured the monometallic character of the chelates having 1:2 (M:L) ratio for copper, cobalt and nickel and 1:1 (M:L) ration for iron and cadmium complexes. The molar conductance data ensured that all the metal complexes are non-electrolytic type of complexes. All the complexes have been proved to have octahedral geometry. The antimicrobial activities of the synthesized metal chelates were evaluated against diferent bacterial and fungal strains. The synthesized ligand and its complexes were also examined as inhibitors for the corrosion of mild steel in 1.0 M H2SO4 at 25 °C using various techniques. The experimental outcomes indicated that the inhibition efciencies of the tested compounds increased as their concentrations increase. The obtained inhibition efciencies were interpreted on the basis of strong adsorption of the inhibitor molecules on the surface of mild steel and composing good protection flms. The adsorption was found to obey Langmuir adsorption isotherm. The results achieved from all applied techniques are obviously compatible.

Degradation kinetics of antibiotics neomycin and streptomycin was explored spectrophotometrically via their oxidation by cerium(IV) in both sulphuric and perchloric acids. The oxidation reactions demonstrated a 1:8 stoichiometry (antibiotic:cerium(IV)). The kinetics of the reactions in the examined acidic media was first-order with respect to [cerium(IV)] and fractional-first orders with respect to examined antibiotics and H+ concentrations. In the perchloric acid solution, the oxidation reactions of both antibiotics manifested fractional-first-order credence in [H+], whereas the reactions that occurred in sulphuric acid solutions displayed negative less than unit order rate with [H+]. Additionally, different behaviours of the reactions in dissimilar acidic media regarding the influence of ionic strength were recorded. Tests for free radical involvement throughout the oxidation reactions were positive. Under the same circumstances, the rates of neomycin oxidation in both acidic media were lower than those of streptomycin, and those obtained in perchloric acid were higher than those of sulphuric acid for both antibiotic substrates. Conceivable oxidation mechanisms in both sulphuric and perchloric acids consistent with the obtained kinetic results were anticipated. Additionally, the derived rate-law expressions in both acids were in good accordance with the obtained kinetic results. The activation parameters of the oxidation reactions in the acidic media were assessed and debated.