Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases

2025-09-24

2025-09-24

CONTENTS

TiO2 thin-film dielectric properties are impacted by annealing

H. D. Chandrashekara — 2025-09-25

Purpose: This study investigates the structural, morphological, and dielectric properties of TiO₂ thin films deposited using the Spray Pyrolysis Deposition (SPD) process and annealed at various temperatures.

Experimental: X-ray diffraction (XRD) analysis confirms the absence of an amorphous phase at 300 °C, while the anatase and rutile phases emerge at 400 °C, 500 °C, and 600 °C, with crystallite sizes increasing from 10.62 to 17.35 nm. Scanning electron microscopy (SEM) reveals a consistent grain growth trend, with grain sizes exceeding XRD estimates. Energydispersive X-ray (EDAX) spectroscopy confirms a stoichiometric Ti:O ratio and uniform nanoparticle distribution. The dielectric properties of Pt/TiO₂/Si MOS capacitors were analyzed, demonstrating improved electrical stability with annealing. Conductance studies indicate a reduction in defect states, enhanced crystallinity, and stable dielectric behavior at higher frequencies. The hysteresis loop analysis reveals decreased losses at 600 °C due to minimized trapped charges and broken bonds. Impedance spectroscopy highlights capacitive behavior, with relaxation peaks at 400 °C, 500 °C, and 600°C, while conductance measurements indicate thermal activation of charge carriers.

Conclusions: These findings suggest that TiO₂ thin films exhibit promising dielectric properties for potential applications in Si-based MOS capacitors and VLSI technology

Synthesis and study of graphene oxide obtained from waste transparent polythene bags using Modified Hummers method

Shireen Shukla — 2025-09-25

Purpose: Plastic industry has seen explosive growth in previous decades over the world. Every sphere of day to day life revolves around plastic products. The used plastic gets accumulated on the Earth s surface and serves as a contaminant causing soil, land and water pollution. Waste plastic needs proper management and elimination from the biotic layer of the ecosystem. Most potent solution is conversion of plastic waste into a functional carbon material. Present workconcentrates on upcycling of waste plastic into economically crucial material that is graphene oxide. The waste polythene bags were successfully converted to graphitic carbon which in turn serves as the base for the synthesis of graphene oxide using modified Hummers method.

Experimental: The analysis was made by studying the FTIR spectra, SEM images and XRD graphs. The FTIR confirms the presence of hydroxyl and carbonyl groups along with carbon carbon interaction. Surface orphology shows the porous and layered structure with an average particle size of 2.74 μm. X ray iffractogram illustrates the crystal structure of the graphene oxide and interlayer spacing.

Conclusions: With the characterisation results, the synthesis of graphene oxide from plastic waste was erified

Crystallographic classification of special grain boundaries

Boris M. Darinsky — 2025-09-25

Object of research: Special grain boundaries in centrosymmetric crystals.

The aim of this work is to classify special grain boundaries in centrosymmetric crystals of all syngonies based on the symmetric properties of plane lattices that are the crystallographic planes of these crystals.

Conclusions: It is shown that the set of geometric parameters identifying special boundaries consists of elements of the symmetry of the plane formed by coinciding atoms that preserve the atomic structure of this plane. Possible misorientations of contacting crystals are found depending on the symmetry of the crystallographic plane for different crystallographic syngonies

Kinetics of electrocrystallization of copper from an acid sulfate solution in the presence of N-methylpolyvinylpyridinemethylsulfate

Evgenia A. Ilina — 2025-09-25

Purpose: In this work, kinetic patterns are established and the main parameters of heterogeneous nucleation and growth of a new phase during electrocrystallization of copper during cathodic deposition from an acid sulfate solution in the presence of N-methyl polyvinylpyridine-methyl sulfate of various molar masses are estimated. The polymer under study is quaternized polyvinylpyridine derivatives and is a promising organic additive for use in the technology of electrochemical void-free filling of through holes (through
silicon vias) of silicon wafers used in microelectronics in the manufacture of microcircuits.

Experimental: Using scanning electron microscopy, it was found that the use of N-methyl polyvinylpyridine-methyl sulfate additive leads to a noticeable decrease in the size of crystallites and blurring of grain boundaries, however, it can contribute to the localized formation of globular formations (if the molecular weight of the polymer is relatively small) or the formation of a layered structure (in the case of high-molecular derivatives). The introduction of a quaternized polymer into a copper plating solution significantly inhibits the electrodeposition process, which includes the stages of irreversible charge transfer and diffusion-controlled electrocrystallization.

Conclusions: It has been found that the activation process of heterogeneous nucleation sites in the presence of a polymer additive is instantaneous regardless of the molar mass. At the same time, as it increases, the density of active nucleation centers decreases significantly

Ternary molybdate K5Cu0.5Hf1.5(MoO4)6: synthesis, structure, thermal expansion and ionic conductivity

Evgeniy V. Kovtunets — 2025-09-25

Objective: A novel ternary molybdate, K₅Cu_0.5Hf_1.5(MoO₄)₆, was synthesized using solid-state ceramic method. The sequence of chemical transformations involved in its formation was determined, revealing that the compound undergoes incongruent melting at 634 °C.

Experimental: The crystal structure was refined using the Rietveld method, revealing a trigonal structure (space group R3c) with unit cell parameters a = 10.5617(2) Å; c = 37.5017(7) Å; V= 3622.9(1) Å3, Rwp = 3.78. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy confirmed the presence of isolated MoO₄ tetrahedra. The electrical conductivity of the title compound reached 7.5·10^–4 S/cm at 550°C, with an activation energy Еа = 0.9 eV. Thermal deformations were investigated by high temperature powder X-ray diffraction (HT-XRD) over the temperature range of 30–500 °C.

Results: K₅Cu_0.5Hf_1.5(MoO₄)₆ was classified as a high thermal expansion material (α_V = 45·10^–6 °C^–1 at 500 °C), and exhibited low anisotropy. Combined results from electrochemical impedance spectroscopy (EIS) and HT-XRD indicated that the endothermic peak observed at 479 °С in the differential scanning calorimetry (DSC) curve corresponded to a first-order phase transition

Dielectric and piezoelectric properties of ceramic material based on modified lead zirconate titanate

Leonid N. Korotkov — 2025-09-25

Purpose: A new high-entropy ferroelectric material 0.9Pb_0.95Sr_0.05(Zr_0.52Ti_0.48)O₃-0.05Pb(Zn_1/3Nb_2/3)O₃-0.05Pb(Mn_1/3Sb_2/3)O₃ was synthesized. At room temperature, it has a tetragonal perovskite-like crystal lattice and is characterized by a high electromechanical quality factor.

Experimental: The dielectric properties was studied in the temperature range of 20 – 500 °C at frequencies of 0.5 – 500 kHz. A noticeable decrease in the temperature of the ferroelectric phase transition (Tm) in сomparison with the base composition Pb_0.95Sr_0.05(Zr_0.52Ti_0.48)O₃ and its diffusion were revealed.

Conclusions: Analysis of experimental data suggests that the material under study is an “intermediate link” between conventional andrelaxor ferroelectrics

Mechanical Properties of Li-Nb-O System Films

Aleksandr V. Kostyuchenko — 2025-09-25

Objective: To quantitatively assess the hardness, elasticity, and plasticity, and to determine the influence of structure and substructure on these parameters in Li-Nb-O system films.

Experimental: Li-Nb-O system films with a thickness of ~0.8 μm were grown on non-heated substrates (oxidized single-crystal silicon wafers (SiO₂ layer ~0.4 μm), single-crystal lithium niobate with (0001) orientation) by ion beam sputtering of a lithium niobate target. Thermal annealing of Li-Nb-O films on substrates was performed in air for 10 min (until complete crystallization) at temperatures of 550, 650, 700, 750, 800, and 850 °C. The heterostructures (film/substrate) were cooled with the furnace. The phase composition of the films was investigated by X-ray diffraction (XRD) and selected area electron diffraction (SAED). The substructure was studied by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM, Tecnai G2 30ST) of cross-sectional specimens prepared by ion milling using a Quanta 3D setup. The surface morphology was investigated by scanning electron microscopy (SEM, Teskan Mira) in the topological
contrast mode and atomic force microscopy (AFM, Solver47). Mechanical properties – hardness (H) and Young's modulus (E) – were determined from nanoindentation (NI, NanoHardness Tester CSM Instruments) measurements using a Berkovich diamond indenter under the following conditions: maximum load 10 mN, loading rate 10 mN/min, and unloading rate 15 mN/min.

Results: It was found that thermal annealing in an oxygen-containing atmosphere at 750°C induces crystallization of quasi-amorphous Li-Nb-O films and the synthesis of single-phase LN films with lattice parameters closest to those of stoichiometric single-crystal LN. The most probable mechanisms of irreversible deformation in LN films are: brittle fracture, plastic deformation of crystallites, and grain boundary sliding. LN films synthesized at 650-750°C are most susceptible to brittle fracture. Brittle fracture occurs due to the buildup of macrostresses in the films, resulting from different coefficients of thermal expansion (CTE) of the film and the substrate. The fracture toughness of the films increases significantly when using a substrate with a CTE close to that of the film. The hardness of nano- and microcrystalline LN films is always higher than the hardness of quasi-amorphous Li-Nb-O system films. The decrease in the hardness of а films synthesized at high annealing temperatures is due to a decrease in the concentration of point defects and an increase in the size of the crystallites

Synthesis of 2-Alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol Derivatives from Vegetable Oils and Their Efficiency as Inhibitors of Hydrochloric Acid Corrosion of Stee

Alexey A. Kruzhilin — 2025-09-25

Purpose: A method for synthesizing new derivatives of 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol from vegetable oils (sunflower, palm, coconut) has been developed.

Experimental: The novelty of the method lies in the use of renewable feedstock – vegetable oils, and in the fact that the method is a onepot process involving oil hydrolysis, the interaction of the fatty acids formed in situ with aminoguanidine bicarbonate, and subsequent alkaline cyclization to a mixture of 3-alkyl-5-amino-1H-1,2,4-triazoles, which were further identified by HPLC/MS. In the second stage, based on these triazole mixtures, the target 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ols of sunflower, palm, and coconut oils were obtained through their two-stage condensation with cinnamaldehyde in the presence of an amphoteric surfactant. The anticorrosion properties of the synthesized triazolopyrimidinols were investigated for St3 steel in 24% HCl using direct (GOST 9.905-82, GOST 9.907-83) and electrochemical (potentiodynamic polarization, Mansfeld polarization resistance method) methods. All derivatives
showed high inhibiting activity at concentrations of 1-2 g/l. The highest efficiency was established for coconut oil derivatives: the protection degree (Z) reached 92.6% (1 g/l) and 98.0% (2 g/l) according to mass-loss measurements, and 97.2-97.4% according to polarization measurements (icor decreased to 0.026-0.028 mA/cm² compared to 6.8 mA/cm² in the background experiment).

Conclusions: It was shown that the high efficiency of the coconut oil derivative mixture is associated with the predominance of mediumchain fatty acid derivatives (C10-C14, of which ~50% are lauric acid residues) in its composition. The obtained compounds represent promising environmentally friendly inhibitors of acid corrosion for the oil production industry

Refinement of the calculation of the efficiency of a chemical generator

Temur T. Muratov — 2025-09-25

Aim of the article: Analitical calculations and preliminary estimates of efficiency of a chemical generators are of great importance for analysis of conversion chemical energy into electrical one, the base which was consist transformation of heterogeneous chemical energy of formation hydrogen molecules into energy of electronic excitation on the surface of catalyst-semiconductors. However in the works cited by the calculation of probability excitation of chemo-electrons (high-energy electrons in conduction band) is not taken into account of the phonon’s channel of the chemical energy accommodation. Such consideration would be by disdain of interaction excited electron with lattice, but in condition of the scattering chemical reaction energy inevitably was shifted of the equilibrium position of oscillators, leading to emission and absorption of phonons. Therefor the technique of the calculation must take into account as electrons as phonons
channels of the accomodation. Aim of given work is derivation of the theoretical formula for efficiency of chemo-generator with provision for thermo-stimuleted transition of electrons to conduction band, with the subsequent analysis of particular cases.

Theoretical part: The influence of local thermal oscillations of crystal were inducted the effect of chemical reaction energy of formation hydrogen molecules on the “catalyst” surface, on velocity generation of the high-energy electrons was theoretical investigated. The formulas for efficiency of generator, clarifying the corresponding formulas from the other works was obtained. It is indicated on an impotant part of thermo-stimuleted transitions of an electrons to the conduction band of the semiconductor at room temperatures.

Conclusions: The results obtained may be useful by qualitatively analysis of the accommodation mechanisms of a chemical energy in the context of problem of conversion a chemical energy to electrical one

Photoluminescent properties of porous silicon nanoparticles: synthesis, characterization, and cellular imaging

Darya A. Nazarovskaia — 2025-09-25

Purpose: This study investigates the stability of photoluminescent (PL) properties of microporous silicon nanoparticles (μpSi-NPs) synthesized by electrochemical etching of monocrystalline silicon followed by lyophilization.

Experimental: Structural analysis revealed a highly porous architecture with < 2-nm pores and silicon nanocrystals (nc-Si) with an average size of 3–5 nm. Fourier-transform infrared spectroscopy confirmed the presence of Si-O-Si bonds, indicating surface oxidation of nc-Si. PL studies demonstrated a broad emission band peaking at 685 nm, attributed to exciton recombination in nc-Si. After 5 months of storage, the PL peak shifted to 655 nm, reflecting oxidation-induced size reduction of nc-Si. Raman spectra showed a 1.5 cm–¹ shift of the Si phonon peak along with spectral broadening, evidencing phonon confinement and partial amorphization. XANES analysis further confirmed increased suboxide content and structural disorder.

Conclusions: Biological experiments demonstrated the biocompatibility of μpSi-NPs and retention of their PL activity, highlighting their potential for biomedical applications such as bioimaging and biosensing

Study of photoluminescence kinetics in bulk GaPN and GaPNAs layers on silicon substrates grown by molecular beam epitaxy

Ekaterina V. Nikitina — 2025-09-25

Objective: The aim of this work is to study bulk GaPN and GaPNAs layers grown by molecular beam epitaxy on silicon substrates. The optical properties of the heterostructures were investigated using photoluminescence. The technique of time-resolved photoluminescence (or photoluminescence kinetics) was employed to evaluate the carrier lifetime in bulk GaPN and GaPNAs layers.

Experimental: An investigation of the influence of the buffer layer on the heterostructure characteristics was conducted. The photoluminescence intensity in the bulk GaPN layer was found to be virtually identical for heterostructures employing either a buffer layer grown by Migration-Enhanced Epitaxy (MEE-GaP buffer) or a GaP buffer layer grown with a gradual temperature ramp from 450 to 600 °C.

Conclusion: It was shown that the lifetime of minority carriers in the bulk GaPN layer grown on a silicon substrate is determined to a greater extent by defects introduced during the nitrogen incorporation into the GaP lattice, rather than by defects caused by growth on silicon substrate

Research on the influence of the powder stoichiometry of (AgxCu1-x)0.7GaSe2 on the phase composition, structure, and lifetime of photogenerated charge carriers

Vladimir V. Rakitin — 2025-09-25

Purpose: This work presents a series of (Ag_xCu_1-x)_0.7GaSe₂ (0 ≤ x ≤ 1) powders synthesized via a solid-state reaction using the presynthesized ternary compounds Cu_0.7GaSe₂, Ag_0.7GaSe₂ and Ag_0.7GaSe₂.

Experimental: A combination of X-ray diffraction (XRD) and Raman spectroscopy was used to establish that the solid solution region in this system is narrow and lies within the range of 0.8 ≤ x < 1.

Conclusions: An investigation of low-temperature luminescence spectra and microwave photoconductivity decay kinetics revealed that single-phase samples exhibit increased lifetimes of photogenerated charge carriers. This is attributed to the replacement of deep charge carrier traps, such as selenium vacancies VSe, with shallower cationic copper vacancies associated with VCu and VSe-VCu

Double borate NaScB2O5: synthesis, thermal stability, ionic conductivity, IR spectroscopy, and electronic structure

Andrey N. Sobolev — 2025-09-25

Purpose: The double sodium scandium borate, NaScB₂O₅, whose crystal structure was solved by Backer and Held in 2001, remains a poorly explored object. The crystal structure has wide channels that may suggest ionic conduction of sodium ions. Based on this, the aim of the study was to investigate the ionic conductivity of this object, as well as to study its thermal behavior, measure the IR spectrum and calculate the electronic structure by quantum chemical method.

Experimental: The synthesis of sodium scandium double borate, NaScB₂O₅, was achieved using a solid-state reaction method. NaScB₂O₅ was explored by using thermal analysis, IR spectroscopy, ionic conductivity, theoretical estimates of activation energy, ion transport pathways, and Ab initio calculations of electronic structure.

Conclusions: Rietveld method was engaged: monoclinic symmetry (sp. gr. P21/c), a = 7.2460(2) Å, b = 9.7887(3) Å, c = 5.9289(2) Å, β = 71.318(1)°, Z = 4, V = 398.37(2) Å3, Rwp = 2.81, GOF = 1.64. NaScB₂O₅ borate is characterized by incongruent melting at 1090 °C. Ab initio calculated IR spectrum of NaScB₂O₅, exhibited a high degree of consistency with the experimentally obtained IR spectrum. The calculated energy barrier
for oxygen ion migration, determined to be 0.998 eV, exhibits a reasonable degree of agreement with the experimentally determined activation energy of 0.9 eV. The title compound exhibits an ionic conductivity of 0.6·10^–3 S/cm at 1023 K. The band gap was about 6.83 eV

Coupled phenomena of concentration polarization in systems with anion-exchange membranes before and after their participation in electrodialysis of tartrate-containing solutions

Olesya A. Yurchenko — 2025-09-25

Objective: Homogeneous anion-exchange membrane ASE and heterogeneous anion-exchange membrane MA-41P were investigated in 20±1 mM Na_xH_(2-x)T solutions with pH 2.5 and 9.0, where T represents the acid residue of tartaric acid. Optical images and contact angles of membrane surfaces, as well as their current-voltage curves and pH of desalinated solutions, were measured before and after using ASE and MA-41P in electrodialysis.

Experimental results: It was established that in alkaline solution, the patterns of concentration polarization development do not differ from those well-known for strong electrolytes. In acidic solution, the ability of tartrates to participate in protonation-deprotonation reactions causes a 4–5 fold increase in the empirical limiting current compared to the theoretical limiting current calculated within the convective-diffusion model. The mechanisms of tartrate transfer through anion-exchange membranes are considered when the desalinated solution mainly contains tartaric acid molecules.

Conclusions: It is shown that long-term operation (about 50 hours) under intensive current regimes leads to the appearance of numerous caverns on the ASE surface and to an increase in the proportion of ion-exchange material on the MA-41P surface. The surfaces of both membranes become more hydrophobic. Analysis of current-voltage curves suggests that electrochemical degradation of the ASE surface and specific interactions of tartrates with weakly basic fixed groups of both membranes lead to reduced proton generation and affect the development of electroconvection

The influence of fullerene C60 on the thermal stability of polyvinyl chloride

Timur T. Sadykov — 2025-09-25

Purpose: Polyvinyl chloride (PVC) is one of the most widely used industrial polymers, yet its practical application is limited by its low thermal and thermo-oxidative stability. The degradation of PVC is accompanied by the elimination of HCl and the formation of isolated and conjugated double bonds, which leads to polymer aging and deterioration of material properties. Despite the availability of numerous
fundamental studies devoted to the degradation and stabilization of PVC, the mechanism of its decomposition remains under discussion, with radical, ionic, and combined pathways being considered. Therefore, the search for efficient stabilizers is still largely empirical. The aim of this work was to reveal the features of thermal and thermo-oxidative degradation of rigid and plasticized PVC in the presence of
fullerene C60.

Experimental: The objects of study included industrial PVC grade S-7059M, fullerene C60, phenolic antioxidants (diphenylolpropane, ionol), and ester plasticizers (dioctyl phthalate, dioctyl sebacate). Thermal and thermo-oxidative dehydrochlorination was carried out at 175 °C in a bubbling-type reactor under nitrogen or oxygen flow. Stabilizing effects were evaluated by the rate of HCl release, thermal stability
time (according to GOST 14041-91), and melt flow index measurements. It was shown that fullerene C60 significantly inhibits PVC dehydrochlorination, reducing the rate of HCl release by more than twofold. The maximum effect is achieved at a content of 0.1 mmol permol of PVC. In plasticized PVC systems, fullerene demonstrated high antioxidative activity, comparable to or exceeding that of industrial phenolic antioxidants. An «echo-stabilization» effect was observed, attributed to the inhibition of ester plasticizer oxidation.

Conclusions: Thus, fullerene C60 can be considered a promising stabilizer for PVC, effectively retarding its thermal and thermo-oxidative degradation. The revealed regularities confirm the predominant role of the radical mechanism in PVC dehydrochlorination and highlight the potential of fullerene for extending the service life of PVC materials

Infrared synchrotron nanovisualization of a biomimetic layer composed of trimethyldihydroquinoline and nanocrystalline hydroxyapatite

Pavel V. Seredin — 2025-09-25

Objective of the article: This study presents the findings of research on a biomimetic organomineral layer composed of trimethyldihydroquinoline, which was polymerized in the presence of nanocrystalline carbonate-substituted non-stoichiometric hydroxyapatite (n-cHAp).

Experimental part: The morphological features of the biomimetic layer were visualized using synchrotron infrared near-field spectroscopy.

Conclusions: It has been demonstrated that the biomimetic layer formed on the surface of dental enamel exhibits a morphological structure characterized by a uniformly distributed and densely packed composite film of poly(2,2,4-trimethyl-1,2-dihydroquinoline-6,7-diol) and n-cHAp. The resulting dental coating, which is based on polydihydroquinoline and nanocrystalline hydroxyapatite, possesses a Vickers hardness coefficient comparable to that of healthy enamel

Synchrotron XANES studies of epitaxial tin-silicon solid solutions nanolayers

Nikolai I. Boikov — 2025-09-25

Purpose: Functional tin and silicon-based materials and thin-film structures based on them are promising objects for microelectronics devices. An important issue for the study and subsequent application of such materials and structures is the properties control under formation technological regimes variations.

Experimental: The specificity of the local atomic surrounding and the features of the electronic structure of tin-silicon solid solutions have been studied by X-ray absorption near edge structure spectroscopy using synchrotron radiation. Nanolayer structures of tin-silicon solid solutions on buffer silicon nanolayers were formed using molecular beam epitaxy.

Conclusions: The possibility of forming an epitaxial tin-silicon solid solution in the concentration range significantly exceeding the known solubility limits of Sn in Si is shown. The rearrangement of the local density of the electronic states of tin and silicon indicates the formation of solid solutions with tin concentrations of 2, 8, and 15 at. %

90 years of the scientific school of solid state physics at Voronezh State University: from solid state physics to nanophysics (Scientific and historical essay)

Evelina P. Domashevskaya — 2025-09-25

90 years of the scientific school of solid state physics at Voronezh State University: from solid state physics to nanophysics (Scientific and historical essay)

Аннотации на английском языке

2025-09-24

Аннотации на английском языке

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