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Лебедев-Степанов, Петр Владимирович

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Институт нанотехнологий в электронике, спинтронике и фотонике

Институт ИНТЭЛ занимается научной деятельностью и подготовкой специалистов в области исследования физических принципов, проектирования и разработки технологий создания компонентной базы электроники гражданского и специального назначения, а также построения современных приборов на её основе. Наша основная цель – это создание и развитие научно-образовательного центра мирового уровня в области наноструктурных материалов и устройств электроники, спинтроники, фотоники, а также создание эффективной инновационной среды в области СВЧ-электронной и радиационно-стойкой компонентной базы, источников ТГц излучения, ионно-кластерных технологий материалов.

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Лебедев-Степанов

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Петр Владимирович

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Теперь показываю 1 - 9 из 9

Только метаданные
Self-Assembly of Fluorescent Photonic Crystal Structures in Binary Water-Glycerol Solvent Droplets
(2020) Savenko, O. A.; Stepko, A. S.; Shevchenko, N. N.; Koshkin, A. V.; Lebedev-Stepanov, P.; Лебедев-Степанов, Петр Владимирович
The morphology of photonic-crystal structures formed by the self-assembly of fluorescent marker nanoparticles from evaporating droplets of a binary water-glycerol solvent, the components of which differ appreciably from each other in the viscosity and evaporation rate, being infinitely mutually soluble under normal conditions, was has been studied experimentally for the first time. It has been shown that the main self-assembly disordering factor is Marangoni vortex flows, and the change in the initial concentration ratio between binary mixture components enables the control over the degree of disordering in the solid phase, which is formed after the solvent is evaporated from a droplet and distributed over the substrate. A low initial concentration of any component corresponds to the most ordered distribution, whereas their medium concentrations correspond to the most disordered distribution. The characteristic values of Marangoni numbers in experiments have been calculated. It has been demonstrated that the average radius of the distribution of an ensemble of marker particles over a substrate may serve as a descriptor for the degree of ordering.
Только метаданные
Studying the Dielectric Properties of the Curcubituril Cavity on the Basis of the Solvatochromic Effect of Styryl Dye upon the Formation of an Inclusion Complex
(2019) Stepko, A. S.; Lobova, N. A.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
A new approach to the theoretical evaluation of the local dielectric properties of media that contain an organic dye acting as a nanoprobe is proposed. The method is checked so as to evaluate the dielectric properties of the host molecule in a supramolecular inclusion complex from the experimentally measured shift of the optical absorption spectrum of the guest molecules (dye) after the complex formation. Using the Onsager-Liptay model, the dielectric properties of the cucurbit[7]uril cavity was theoretically estimated by analyzing the experimentally measured shift of the absorption spectrum of 1-(3-ammoniopropyl)-4-[(E)-2-(3,4-dimethoxyphenyl)-ethenyl]-pyridinium dication of the dye after it forms a complex with cucurbit[7]uril in an aqueous solution. To parameterize the Onsager-Liptay equation, the positions of the absorption spectral maxima of the dye under study were experimentally measured in the following solvents with known dielectric and optical properties: methanol, ethanol, 1-propanol, 1-butanol, and water. When calculating molecular structures, dipole moments of the ground and excited states, and polarizability, the TD-DFT quantum chemical method with the CAM-B3LYP functional in the 6-311G(d,p) basis set was used within the Gamess (United States) software package. The obtained theoretical value of the effective dielectric permittivity of the cavity (about 13) is in good agreement with the published value.
Только метаданные
Study of the 3D Structure of a Hydrogel with Gold Nanoparticles by Cryogenic Electron Microscopy
(2022) Mikhutkin, A. A.; Kamyshinsky, R. A.; Kuznetsov, N. M.; Lebedev-Stepanov, P. V.; Stepko, A. S.; Vasiliev, A. L.; Лебедев-Степанов, Петр Владимирович
A hydrogel with gold nanoparticles stabilized in a citrate buffer is obtained by dehydration from a solution (sol-gel transition). The morphological characteristics of the hydrogel are studied using cryogenic transmission electron microscopy, in particular cryoelectron tomography. The spatial structure of the hydrogel is studied in three dimensions. The dimensional parameters of the nanoparticles and distances to nearest neighbors are determined. It is found that most of the nanoparticles are in a bound state and form clusters in the process of hydrogel formation. © 2022, Pleiades Publishing, Ltd.
Только метаданные
Specific Solvation of a 4-DASPI Dye in a Water–Ethylene Glycol Binary Solvent
(2022) Stepko, A. S.; Medvedeva, A. A.; Koshkin, A. V.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
Abstract: The solvatochromic shifts of the maxima of the absorption spectra of a 4-DASPI dye (4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide) in a water–ethylene glycol binary solvent in a range of concentrations of 0–100% are experimentally studied. The dependence of the solvatochromic shift on the macroscopic permittivity (dielectric constant) of the solution and concentration of ethylene glycol is constructed. The Onsager–Liptay model is applied for the theoretical interpretation which makes it possible to estimate the effective permittivity in the microscopic region directly adjacent to the chromophore based on the values of the measured solvatochromic shifts. It is found that the value of the permittivity in the solvate shell of this dye substantially differs from the macroscopic value of this quantity, which means that the shell is significantly enriched with ethylene glycol (specific solvation) throughout the entire range of concentrations, and the enrichment reaches a maximum approximately in the middle of the specified range. The composition of the solvate shell of the dye at different values of the concentration is discussed. © 2022, Pleiades Publishing, Ltd.
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Structure Visualization of 4-DASPI–Cucurbituril Supramolecular Complex to Predict the Solvatochromic Shift of Absorption Spectrum
(НИЯУ МИФИ, 2024) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
The study of supramolecular “host-guest” complexes in solutions is of fundamental and practical significance. The structures and formation enthalpy of supramolecular complexes for the 4-DASPI dye with two cavitands (cucurbit[6]uril and cucurbit[7]uril) have been obtained by the TDDFT quantum chemistry method with a camb3lyp basis. It was shown by visualization of the structures that the size of cucurbit[6]uril is too small and doesn’t allow the dye chromophore to penetrate into the cavitand cavity while the dye stays in the ground state, but the formation of an external complex is possible. On the contrary, formation of an inclusion complex with the cucurbit[7]uril is energetically favorable, and the dye chromophore penetrates into the cavity. Visualization of the complex structure allows us to determine the chromophore position relative to the given cavitand cavity, and thus we can predict the changes in the dye spectra due to complexation. The theoretical results of the work are in good correlation with the experiment.
Только метаданные
Microstructure and Rheological Behavior of Stabilized Gold Nanoparticles Hydrosol
(2021) Kamyshinsky, R. A.; Kuznetsov, N. M.; Stepko, A. S.; Chvalun, S. N.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
© 2021, Pleiades Publishing, Inc.Abstract: A comprehensive analysis of an aqueous solution of gold nanoparticles with an average size of 6 nm in a citrate buffer has been carried out, with investigation of the solution rheology and structure by electron and atomic force microscopy. A deviation of the rheological behavior of hydrosol from the Newtonian properties is found even at low gold nanoparticle concentrations. The specific features of the rheological behavior of hydrosol are explained based on the transmission electron microscopy (TEM) data.
Открытый доступ
Computation of dielectric properties of nano-probe local surroundings by solvatochromic spectral shift measurement of organic dye molecule
(2019) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
© Published under licence by IOP Publishing Ltd. Study of dielectric properties of the macrocyclic molecules cavity that can form inclusion complexes with dye molecules is an important problem. Changes in absorption spectra of chromophore inserted into macrocyclic cavity with the formation of the supramolecular complex can be considered as solvatochromic shift. This shift caused by changes of dielectric properties of the environment around the chromophore when it moves from water solution to macrocyclic cavity. Theoretical model that can describe the effective dielectric permittivity of the cavity allows predicting solvatochromic spectral shift of dye molecules due to non-covalent supramolecular complexation. Such a dye molecule could apply as a nano-probe for measurement of the effective dielectric constant of any local surrounding media in which its chromophore can be inserted.
Открытый доступ
Estimation the dielectric properties of solvation shells and nano-cavities by solvatochromic shift of organic dye
(2021) Stepko, A. S.; Savenko, O. A.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
© Published under licence by IOP Publishing Ltd.We investigated the preferential solvation effect of pyridinium-N-phenolate betaine (organic dye) taken as a molecular probe in two binary solvents (water-BuOH and water-BuNH2) in concentration range 0-100%. The Onsager-Liptay model was used to connect the spectral solvatochromic shift in solvation shell of the dye with the dielectric permittivity of the environment around its chromophore. That makes it possible to estimate the effective dielectric constant in the microscopic region of the probe, based on the values of the experimentally measured solvatochromic shifts. It was shown that the solvation shell of the dye is significantly depleted with the second component of binary solvent in water solution. It is true both for the water-BuOH and water-BuNH2 solvents. The absolute spectral shift in case of water-BuNH2 solvent is greater than in the second case. However, the relative depletion is stronger in case of water-BuOH. The innovative potential of the method is in the development the nanoprobe devices to measure the dielectric constant of small objects and nano-regions, to control instantaneous solvent concentration into evaporating sessile droplet of binary solvent in different zones of the droplet.
Открытый доступ
Structure Visualization of 4-DASPI–Cucurbituril Supramolecular Complex to Predict the Solvatochromic Shift of Absorption Spectrum
(2024) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович
The study of supramolecular ў??host-guestў?? complexes in solutions is of fundamental and practical significance. The structures and formation enthalpy of supramolecular complexes for the 4-DASPI dye with two cavitands (cucurbit[6]uril and cucurbit[7]uril) have been obtained by the TDDFT quantum chemistry method with a camb3lyp basis. It was shown by visualization of the structures that the size of cucurbit[6]uril is too small and doesnў??t allow the dye chromophore to penetrate into the cavitand cavity while the dye stays in the ground state, but the formation of an external complex is possible. On the contrary, formation of an inclusion complex with the cucurbit[7]uril is energetically favorable, and the dye chromophore penetrates into the cavity. Visualization of the complex structure allows us to determine the chromophore position relative to the given cavitand cavity, and thus we can predict the changes in the dye spectra due to complexation. The theoretical results of the work are in good correlation with the experiment.