В работе исследованы особенности морфологии и свойств дисперсных порошков ZnO, полученных полимерно-солевым синтезом при использовании поливинилпирролидона. Процессы термической эволюции материалов при синтезе порошков были исследованы методом дифференциально-термического и термогравиметрического анализа. Кристаллическая структура, морфология, люминесцентные и адсорбционные свойства синтезированных нанопорошков были изучены методами рентгенофазового и электронно-микроскопического анализов, оптической и люминесцентной спектроскопии. Установлено, что добавки поливинилпирролидона уменьшают размер формирующихся кристаллов ZnO и оказывают существенное влияние на морфологию, люминесцентные и адсорбционные свойства материалов.

В статье приведены результаты исследований фотостимулированных процессов кристаллизации в стеклах и стеклокристаллических материалах системы MgO-Al2O3-TiO2-SiO2, модифицированных диффузией серебра ионообменной обработкой в солевом расплаве AgNO3/KNO3 при различных температурах, УФ-облучением и дополнительной одноступенчатой термической обработкой. Полученные материалы были исследованы методами оптической и люминесцентной спектроскопии, рефрактометрии, рентгенофазового анализа и измерениями микротвердости. Облучение стекол, подвергнутых ионообменной обработке, приводит к образованию и росту молекулярных кластеров и наночастиц серебра, которые играют роль центров кристаллизации и ускоряют кристаллизацию стекла в процессе его дополнительной термообработки. Экспериментально установлено влияние УФ облучения на показатель преломления и микротвердость прозрачных и опалесцирующих стекол и стеклокристаллических материалов, полученных при дополнительной термообработке стекол, подвергнутых ионному обмену. Հոդվածում ներկայացված են MgO-Al2O3-TiO2-SiO2 համակարգի՝ արծաթի դիֆուզիայի միջոցով մոդիֆիկացված, ապակիների և ապակեբյուրեղային նյու-թերի ֆոտոստիմուլացված բյուրեղացման պրոցեսների ուսումնասիրության արդյունքները: Ապակիները մոդիֆիկացվել են իոնափոխանակային մշակմամբ AgNO3/KNO3 աղերի հալույթում տարբեր ջերմաստիճաններում, ՈՒՄ ճառա-գայթմամբ և լրացուցիչ մեկաստիճանային ջերմային մշակմամբ: Ստացված նյութերն ուսումնասիրվել են օպտիկական և լյումինեսցենտային սպեկտրասկոպիայի, ռեֆրակտոմետրիայի, ռենտգենաֆազային վերլուծության եղանակներով և միկրոկարծրության չափումներով: Իոնափոխանակման ենթարկված ապակիների ճառագայթումը հանգեցնում է մոլեկուլային կլաստերների և արծաթի նանոմասնիկների ձևավորման ու աճի, որոնք հանդես են գալիս որպես բյուրեղացման կենտրոններ և արագացնում են ապակու բյուրեղացումը նրա լրացուցիչ ջերմային մշակման ժամանակ։ Փորձնականորեն հաստատվել է ՈՒՄ ճառագայթման ազդեցությունը թափանցիկ և օպալեսցենտային ապակիների և ապակեբյուրեղային նյութերի բեկման ցուցիչի և միկրոկարծրության վրա, որոնք ստացվել են իոնափոխանակության ենթարկված ապակիների լրացուցիչ ջերմային մշակմամբ: The article presents the results of studies of photostimulated crystallization processes in glasses and glass-crystalline materials of the MgO-Al2O3-TiO2-SiO2 system modified by silver diffusion. The glass was modified by ion-exchange processsing in AgNO3/KNO3 salt melt at different temperatures, UV irradiation and an additional one-step thermal treatment. Received materials were studied using optical and luminescent spectroscopy, refractometry, X-ray phase analysis and microhardness measurements. Irradiation of glasses subjected to ion-exchange treatment leads to the formation and growth of molecular clusters and silver nanoparticles, which play the role of crystallization centers and accelerate the crystallization of glass during its additional heat treatment. The effect of UV irradiation on the refractive index and microhardness of transparent and opalescent glasses and glass-crystalline materials obtained by additional heat treatment of glasses subjected to ion exchange has been experimentally established.

Porous nanocomposites based on oxide compounds of zinc and manganese are synthesized and their structure, morphology, spectral and photocatalytic properties are studied. It is shown that the resulting porous oxide composites have photocatalytic properties and consist of ZnO, Mn3O4 and ZnMn2O4 nanocrystals with a size of 20–40 nm. The introduction of Mn2+ ions into the crystal lattice of ZnO causes a increase in the size of the unit cell of crystals. The band gap of the composites is 3.26 eV. The kinetics of photocatalytic decomposition in a Chicago Blue Sky dye solution is described by a pseudo-first order equation. In the presence of porous nanocomposites, the processes of oxidation of organic compounds proceed both on the surface of photocatalysts and in solution. The synthesized nanocomposites are promising for use in photocatalytic systems for water purification from organic contaminants.

Composite sol-gel materials of the MgO–Al 2 O 3 –ZrO 2 –SiO 2 system were synthesized and the processes of their thermal evolution and crystallization were studied. Application of sol-gel compositions of the MgO–Al 2 O 3 –ZrO 2 –SiO 2 system to the surface of quartz ceramics leads to a significant increase in the mechanical strength of the material. The processes of thermal evolution of the sol-gel composition were studied using IR spectroscopy, X-ray diffraction, electron microscopy, and energy dispersive analysis. It was shown that the formation of the oxide composite structure of materials begins at the stage of wet gels. Treatment of quartz ceramics with composite sols followed by drying and heat treatment up to 1200°C results in modification of the surface layers of the material, which makes it possible to increase the mechanical strength of the material by more than 20%. Sol-gel modifying compositions, upon drying and subsequent heat treatment, form polycrystalline structures bonded to quartz ceramic particles and consisting of various oxide crystals.

Experimental results on photobleaching of Chicago Sky Blue diazo dye solutions using ZnO/ZnAl2O4/Cu photocatalytic nanocomposites are presented. Data on the crystal structure and morphology of these nanocomposites obtained by the polymer-salt method are presented. The results of studies of the kinetics of the processes of photobleaching of dye solutions and its adsorption on the surface of powdered nanocomposites showed that the experimental data correspond to known kinetic models using the first and second order rate equations for these processes.

The possibility of detection of methane using fiber-optical sensor with ZnO-SnO2-Fe2O3 photocatalyst was demonstrated. Photocatalytic composite sensor element was prepared by non-isothermal polymer-salt method from solutions of inorganic metal salts and polyvinylpyrrolidone. Optical detection is carrying out by Bragg diffraction grating of fiber-optical sensor at the temperature variations during photocatalytic methane oxidation.

This study examines the features of the morphology and properties of disperse ZnO powders obtained by polymer-salt synthesis using polyvinylpyrrolidone (PVP). The processes of the thermal evolution of materials during the synthesis of powders are studied by differential thermal and thermogravimetric analysis. The crystal structure and morphology, as well as the luminescent and adsorption properties, of the synthesized nanopowders are studied by X-ray diffraction and electron microscopy analysis, as well as optical and luminescence spectroscopy. It is established that the addition of PVP reduces the size of the formed ZnO crystals and has a significant effect on the morphology, as well as the luminescent and adsorption properties, of the materials.

This paper describes the low-temperature polymer-salt synthesis of ZnO–Ag nanopowders and presents the results of studying their structure, morphology, and properties. The methods of X-ray phase analysis and electron microscopy are used to study the structure and morphology of materials. It is found that the resulting nanopowders consist of nanoparticles of about 30 nm. The experiments show that the resulting nanopowders have antibacterial activity against both gram-positive and gram-negative bacteria.

This article presents the results of a study of the effect on the adsorption properties of microporous glass of its modification with ZnO–Ag nanocrystals. The adsorption processes from solutions of the Chicago Blue Sky organic dye are studied by spectrophotometric methods. It is found that the introduction of ZnO–Ag nanocrystals into glass pores increases the adsorption capacity of the material. It is shown that in concentrated (>10–6 M) Chicago Blue Sky dye solutions adsorption processes compete with the aggregation of dye molecules in solutions.

The problems of manufacturing nanoscale Gd2O3:Nd3+ phosphors using the liquid polymer-salt method have been considered. Within the framework of this method, the dual role of polyvinylpyrrolidone (PVP) as an organic solvent in the synthesis process has been determined. On the one hand, it stabilizes the formation of Gd2O3 crystals, preventing their uncontrolled growth and agglomeration, and on the other, it serves as a fuel during decomposition (combustion), contributing to an increase in the reaction temperature and thereby influencing the structural and emission properties of phosphors. It has been shown that successive drying of the initial homogeneous solution containing gadolinium and neodymium salts, as well as PVP, at room temperature for 24 h and heat treatment at 1000°C for 2 h make it possible to obtain high-luminescent near-infrared phosphors Gd2O3:Nd3+, whose crystals are characterized mainly by a cubic structure and an average size of about 40 nm. It has been experimentally confirmed that the developed method is suitable for modifying hollow-core antiresonant optical fibers made of silica glass with thin-film coatings based on the synthesized material and does not cause structural and phase transformation of the formed Gd2O3 crystals. It has been found out that the emission spectra of the nanoscale Gd2O3:Nd3+ phosphors obtained by the polymer-salt method at temperatures of 550 and 1000°C are identical, namely: (1) the shape of the luminescence peaks is the same for both specified heat treatment regimes regardless of intensity, (2) the main lum-inescence peak is located near 1064 nm wavelength and corresponds to the electron transition 4F3/2–4I11/2, and (3) additional luminescence peaks are located near 900 and 1340 nm wavelengths and correspond to the 4F3/2–4I9/2 and 4F3/2–4I13/2 electron transitions, respectively.

The synthesis of ZnO-MgO nanocomposite via modified Pechini method was performed. The crystalline structure and the morphology of nanocrystals were studied by X-ray diffraction analysis and scanning electron microscopy. The study on the kinetics of diazo dye adsorption and its photocatalytic decomposition on the surface of nanocomposite was performed. It was shown that the rate of adsorption process in aqueous solution is described by a kinetic equation of the first order. The application of the nanocomposite allows to significantly increase the efficiency of UV water treatment and its purification from the dye. However, a brief deviation of experimental data on the rate of photocatalytic degradation from the values of the widely used kinetic equation of the first order is observed.

In this study, composite Ag/AgBr/Zn(NO3)2/PVP coatings are synthesized from solutions and their structure and luminescent properties are studied. It is shown that the luminescent properties of aqueous solutions and Ag/AgBr/Zn(NO3)2/PVP composite coatings formed from them are largely determined by the presence in the structure of materials of various small Agn (n < 5) molecular clusters. The formation of AgBr particles is accompanied by a change in the shape of the luminescence spectra, which indicates the evolution of the sizes and concentrations of various Agn molecular clusters when introducing bromide anions into the composition of materials.

Photoactive Cu-containing ZnO-ZnAl2O3 nanocomposites were synthesized by the polymer-salt method. To study the structure and properties of materials, the methods of luminescent spectroscopy and X-ray phase analysis were used. It has been shown that the resulting nanocomposites are capable of photogeneration of singlet oxygen under the action of UV and blue light. The synthesized materials consist of nanosized hexagonal ZnO crystals and cubic ZnAl2O4 crystals doped with Cu. The study of luminescent properties showed that nanocomposites can be used as down-converters of light that convert radiation from the UV-C range to UV-A and the visible spectral range.

Experimental results of polymer-salt synthesis of Yb:YAG nanopowders and analysis of their structure and luminescent properties are presented. Infrared absorption spectra of synthesized materials are presented. The results of XRD analysis show that Yb:YAG nanocrystals with sizes of 18-35 nm form at a temperature of 900-1100 °С. The study on photoluminescence spectra and decay curves shows that properties of synthesized powders are close to properties of macroscopic materials produced by traditional high-temperature methods.

Photoactive ZnO-SnO2-Ag(AgCl) nanomaterials have been prepared by polymer-salt method. Prepared materials able to generate singlet oxygen under UV and blue light irradiation. Materials structure and properties have been studied by optical and luminescence spectroscopy, XRD and SEM analysis. It was found that the structure of ZnO-SnO2-Ag(AgCl) materials consists of hexagonal ZnO, tetragonal SnO2, Ag and AgCl crystals having size 50÷60 nm. Obtained materials able to generate chemically active singlet oxygen under UV irradiation and have high bactericidal properties against both gram-positive and gram-negative bacteria. The increase of Ag content enhances the bactericidal properties of prepared materials.

Приведены результаты исследований влияния поливинилпирролидона на структуру и оптические свойства нанокомпозитов ZnO-MgO, полученных полимерно-солевым методом. Синтезированные нанокомпозиты исследованы методами оптической и люминесцентной спектроскопии и рентгенофазового анализа. Увеличение содержания этого полимера в растворах приводит к уменьшению размеров формирующихся кристаллов ZnO, увеличению интенсивности люминесценции нанокомпозитов ZnO-MgO в синей части спектра и к ее подавлению в длинноволновой части. Эффективность фотогенерации синглетного кислорода нанокомпозитами ZnO-MgO, полученными полимерно-солевым методом, возрастает при повышении содержания поливинилпирролидона в исходных растворах. Ключевые слова: люминесценция, спектры, кристаллы, ZnO, синглетный кислород.