Topological indices are numerical invariants of molecular graphs and are beneficial for predicting the physicochemical properties of chemical compounds. In this view, a topological index can be considered as a score function which maps each molecular structure to a real number. In the past two decades, tungsten trioxide (WO₃) nanostructures have been extensively studied for their diverse technological applications. They have received greater attention by researchers, owing to their novel functionalities and unique physicochemical properties. We, for the first time, compute the Sum Connectivity index, Variable Sum index, ABC index, Harmonic index, Ordinary Geometric Arithmetic index, SK indices, Forgotten index, Symmetric Division index, Augmented Zagreb index, Inverse sum index, IRM index, Modified second Zagreb index, Inverse Randic index,´ Albertson and Bell topological indices of cubic structured WO₃ [l, m, n] nanomultilayer. We also present a graphical analysis of all indices with respect to the dimension of this nanomultilayer.

In the zero-range potential model and in the effective mass approximation, dispersion equations have been obtained, that describe dependence of the average binding energies of the quasistationary g- and u-states of the- center in the QD, as well as the widths of energy levels on the magnitude of the external electric field and the parameters of 1D-dissipative tunneling. Dips in the field dependences of the binding energies average values for quasi-stationary g- and u-states have been revealed. It is shown that the field dependences of the energy level widths for the g- and u- states of the-center have a resonance structure at the external electric field strengths corresponding to the dips in the field dependences of the average binding energies.

In the dipole approximation, the field dependence of the probability of the electron radiative transition from a quasistationary u-state to a quasi-stationary g-state of the-center in a QD in the presence of dissipative tunneling with the participation of two local phonon modes has been calculated. It was found that the curve of the radiative transition probability (RTP) dependence on the strength of the external electric field contains three peaks.

Zinc sulfide particles layer were grown on FTO glass and stainless steel substrates by electrode position technique from aqueous solution that contained 0.1 N zinc sulfate, 0.1 N sodium thiosulfate and 0.1 N triethanolamine was used as complexing agent. The deposing potential was analyzed by cyclic voltammetry technique. The ZnS particle growth was studied in the range of deposition time from 10 to 40 minutes. The thickness of layer was found to be the highest, 3.92 µm, at 20 min. The various percentage of complexing agent, pH of solution and thicknesses of film were characterized by scanning electron microscope (SEM) and UV-Visible spectrophotometer. The effects of complexing agent, pH of solution and thickness of layer on morphological and optical properties of ZnS were investigated. The Electrical resistivity of ZnS was found thickness dependent. The Chemical Composition of ZnS particles analysed by EDAX (Energy Dispersive Analysis by X-ray).

A novel, eco-friendly and low temperature synthesis of tin (II) monosulfide colloid particles is described. Chemical bath deposition was successfully applied for the deposition of polynanocrystalline SnS from acidic aqueous solutions. The characterization of the prepared samples was accomplished through elemental analysis, scanning electron microscopy, X-ray powder diffraction, and optical spectroscopy. The composition of tin (II) monosulfide colloids assembled of nanoparticles was found to be Sn-rich. Several simple scenarios for Sn surplus within SnS lattice (Svacancies at S-sublattice, Sn-atoms intercalated between SnS layers and Sn-doping of S-sites) have been analyzed by means of quantum chemical calculations. The potential application of the Sn_1+xS colloid particles in solar cells as absorber material and as photocatalyst was demonstrated by measuring the optical properties.

Zinc sulfide (ZnS) and zinc sulfide/lead sulfide (ZnS/PbS) nanorods were grown on glass substrates using a thermal evaporation method. The morphology of the prepared samples has been studied by transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) and Scanning Electron Microscopy (SEM). Both differences and similarities in morphology between the samples have been discovered. In the ZnS/PbS sample, ZnS nanorods were formed with diameter less than 50 nm and length between 2000 and 3000 nm. The pure ZnS sample has dense structure and its thickness was about 200 nm. Samples were studied in detail using energy-dispersive X-ray spectroscopy (EDX). The surface chemical compositions of the samples were confirmed by means of X-ray photoelectron spectroscopy (XPS). The determination of the crystal structure using the X-ray diffraction revealed that two phases of ZnS, blende and wurtzite, are present in the sample after adding Pb, while only blende is identified in the pure ZnS sample.

The presented work revolves around exploration of the structural dependence of electronic properties of zinc selenide nanowire. For this purpose the shapes under consideration are 2 atom linear wire, 2 atom zigzag wire, 4 atom square wire and 6 atom hexagonal wire for zinc selenide. ABINIT code has been used for the study. The band structure, geometrical optimization and stability of proposed structures have been studied. A 4 atom square nanowire structure has come out to be comparatively more stable than other proposed structures while the findings of the study for band structure reveals that zinc selenide nanowires may have conducting, semi conducting or insulating nature which depends on the proposed geometry of the nanowire.

An approach to structural and functional modelling of the oxyfluorinated nonwovens based composite materials has been developed. The structural component of the model is presented in the form of integral and differential characteristic functions of the planar heterogeneity. The correlation analysis methods revealed the existence of links between the latex sorption capacities and the nanostructural characteristics of the experimental samples’ SEM-images. The obtained functional-structural model allows us to quantify the expected values of sorption capacities of the nonwoven fiber materials under the certain restrictions on the chemical compositions of the impregnating mixtures.

Magnetic properties of porous spheres BiFeO₃ have been studied at temperatures ranging from 2 to 300 K. A transition to cluster spin glass state has been detected in the region of about 100 K. The presence of the transition is confirmed by nonlinear variation of coercive force and the appearance of exchange displacement of magnetic hysteresis loops at temperature below 100 K. Temperature dependence of magnetization for zero-field cooled regime exhibit a maximum at some temperature T_m. The function T_m(H) (H is magneic field) changes in accordance with Almeida–Thouless line. The performed measurements of the frequency dependence of AC susceptibility confirm the behavior of spin glass with spin freezing temperature T_f = 116 K. The critical index zν = 2.5 agrees well with the mean-field theory zν = 2.0.

Vanadium oxides V₂O₅ and V₂O₃ have been synthesized by ultrasonic spray pyrolysis in the form of nanostructured spherical agglomerates with an average diameter of 0.5–1.5 µm. By changing the synthesis conditions, the vanadium oxidation state and microspheres surface morphology can be varied. The microspheres of V₂O₅ are formed during aerobic synthesis, while V₂O₃ microspheres are produced under an atmosphere of argon. An increase in the concentration of the initial solution leads to an increase in both size of V₂O₅ nanoparticles and the diameters of the V₂O₅ microspheres. Long-term storage of V₂O₃ in air results in morphological degradation of the microspheres.

In this article, monoclinic tungsten tri-oxide (m-WO₃) nanoparticles (hereafter NPs) were prepared by facile precipitation method and they were successfully examined as gas sensing materials for monitoring gaseous ammonia at room temperature have been reported. The effect of calcination temperature on structural and morphological properties of the prepared samples were also investigated. Physicochemical properties of the samples were characterized by XRD, SEM, XPS, UV-Vis and PL analysis. XRD studies confirmed the monoclinic structure of the prepared NPs. Optical studies disclosed that the obtained samples were having wider optical band gaps ranging from 2.48 to 2.76 eV. Sensing signatures such as selectivity, transient response along with performance indicators like repeatability and stability have also been investigated. Invitingly, the sample calcined at 823 K exhibited highly improved sensing response of 142 towards 200 ppm of ammonia with rapid response/recovery time of 26 / 79 s.

This paper aims to study the photocatalytic properties of strontium aluminate phosphors. The rare earth doped strontium aluminate was synthesized by combustion method. The photocatalytic property was studied by absorption of methyle orange in aqueous solution under solar radiation. Eu:Dy codoped SrAl₂O₄ shows better photocatalytic properties than Eu or Dy doped or Eu, Dy, Ho codoped SrAl₂O₄. Structural and morphological characterization was done by X-ray diffraction, SEM, EDX techniques.

Nickel-zinc ferrites are important industrial materials in the production of various types of microwave devices; therefore, studies of new methods of obtaining functional ceramic on their basis are of great interest at present. In this work, soft magnetic ceramics based on Ni_0.4Zn_0.6Fe₂O₄ spinel ferrite with low values of the coercive force were successfully obtained under various sintering modes (1000 and 1100 ^◦C, holding time – 16 hours) based on nanostructured pre-ceramic ferrite powder synthesized by the solution combustion method. The initial powder and sintered ceramics were investigated by EDX, SEM and PXRD methods. The electromagnetic parameters of the final product were investigated by vibration magnetometry and using the method of rectangular waveguide transmissions in the X-band. It was shown that, depending on the selected sintering mode, it is possible to obtain magnetic ceramics with an average grain size in the range from 1 to 3 µm and with values of the coercive force (H_c) from 16.32 to 19.41 Oe, remanent magnetization (M_r) from 3.39 to 4.31 emu/g and saturation magnetization (M_s) from 67.90 to 78.42 emu/g. After the preparation of a ferrite-polymer composite with different content of Ni_0.4Zn_0.6Fe₂O₄ (0–50 wt%), it was found that the highest absorption characteristics of electromagnetic waves were observed for the sample with 40 wt% of spinel ferrite obtained at 1100 ^◦C, 16 hours sintering mode.

Using the thermodynamic and kinetic approaches, it was found that Cu(NH₃) complex predominating at 23^◦C spontaneously decomposes at elevated temperatures, forming CuO precipitate in a bulk solution and a layer (CuO||SiO₂) on the surface of silica glass. The rates of these heterogeneous processes are fairly well described by the 1st-order reaction of decay of the Cu(NH₃)complex. The formation of the CuO precipitate and layer is a two-step kinetic process. The rate of precipitate formation dominates above 65 C while the rate of the layer formation prevails below this value. The CuO||SiO₂ material synthesized below 65^◦ possesses an optical bandgap of (1.25±0.05) eV, which is smaller compared to the crystals of commercial CuO. The CuO||SiO₂ material displays a photocatalytic activity in the reaction of UV-decomposition of benzoquinone-hydroquinone. It was discovered that the photocatalytic activity depends on the thickness of the photocatalyst layer.

In this work first described the new relatively simple approach to the synthesis of nanolayers of Ni-doped CuO via of Successive Ionic Layer

Deposition (SILD) method. The study of Ni-doped CuO nanolayers, synthesized of SILD, has been carried out by HRTEM, XRD, FTIR and XPS spectroscopy methods; it was demonstrated that they had been formed of nanorods with dimensions of about 10–15 nm and tenorite crystal structure CuO were formed. The research electrochemical properties of nanolayers were carried out in 1 KOH solution by using techniques of cyclic voltammetry and galvanostatic curves method. The electrochemical study of nickel foam electrodes modified by Ni-doped CuO nanolayer prepared by 30 SILD cycles demonstrates that specific capacitance is 154 mAh/g (1240 F/g) at current density 1 A/g. Repeated cycling after 1000 charge-discharge cycles demonstrates 8% capacitance fade from the initial value, so such electrodes may be used as effective electroactive materials for alkaline battery and pseudocapacitors.