Перегляд за Автор "Gevelyuk, Serhii A."
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Документ An Interferometric Method of Inner surface Morphology Investigation in Porous Glass(Одеський національний університет імені І. І. Мечникова, 2005) Gevelyuk, Serhii A.; Doicho, Ihor K.; Mak, Vasyl T.; Safronsky, E. D.; Vorobyova, V. A.A method of inner surface morphology investigation in porous glass using modified Michelson’s interferometer is presented. The possibility of residual silica gel detection in pores by interferometric measurements is shown. The method also allows to distinguish the role of compressing and stretching forces in the mechanical deformation of porous samples. The proposed method is convenient to study the effect of additional treatments on the removal of residual silica gel out of porous glasses. Interferometric measurements make it possible to minimize the mechanical deformations of a porous layer on a solid substrate by tuning the layers thickness ratio.Документ Dependence of photoluminescence of nanoparticle ensembles of stannum (IV) complexes in silica porous matrix on concentration of saturating solution(Одеський національний університет імені І. І. Мечникова, 2016) Gevelyuk, Serhii A.; Rysiakiewicz-Pasek, E.; Doicho, Ihor K.; Гевелюк, Сергій Анатолійович; Ришякевич-Пасек, Е.; Дойчо, Ігор Костянтинович; Гевелюк, Сергей Анатольевич; Рысакевич-Пасек, Е.; Дойчо, Игорь КонстантиновичDependence of photoluminescence of high-molecular nanoformations of dyes on the basis of stannum (IV) complexes in porous glass on concentration of saturating solution has been researched. The results have been compared with photoluminescence of corresponding solutions, in which the effect of concentration quenching, was due to the Franck-Condon principle, was observed. It was found that intensity of luminescence for nanoparticle ensembles was always higher than in solution. At that, decrease of luminescence intensity alongside with concentration growth of saturating solution was observed as well. However, the observed dependence was more complicated than in solution. It can be explained by the fact that the pores with maximal sizes are filled at large concentrations of saturating solution of dye. The dye particles act almost the same as in solution, where photoluminescence is fainter, in such pores.Документ Influence of y-irradiation on photoluminescence of porous germanium obtained by treatment in electric spark discharge(Одеський національний університет імені І. І. Мечникова, 2001) Gevelyuk, Serhii A.; Doicho, Ihor K.; Kovalenko, M. P.; Lishchuk, D. E.; Mak, Vasyl T.; Prokopovich, L. P.; Chistyakov, V. P.The porous Ge layers are produced by spark discharge method. The photoluminescence spectra of these layers are compared with ones for porous Ge obtained by stain, chemical and electrochemical etching. There are the data in references that for porous Ge layers obtained by different methods the maximum for photoluminescence spectrum may be localized by two different wavelengths depending on the production procedure. In contrast to it, our spectra consist of both peaks. Using the results of photoluminescence spectra studies, the comparison of aging effects for porous Ge layers produced by different methods was made. The influence of у-quanta action on photoluminescence spectra of porous Ge layers was studied.Документ Optical and structural properties of TіO2 nanofibers prepared by the electrospinning method(2011) Tereshchenko, Alla V.; Kusevitch, A.; Viter, Roman V.; Smyntyna, Valentyn A.; Buk, J.; Macak, J. M.; Gurov, A.; Konup, Ihor P.; Gevelyuk, Serhii A.; Терещенко, Алла Владимировна; Кусевич, А.; Витер, Роман Витальевич; Смынтына, Валентин Андреевич; Бук, И.; Макак, М.; Гуров, А.; Конуп, Игорь Петрович; Гевелюк, Сергей Анатольевич; Терещенко, Алла Володимирівна; Кусевич, А.; Вітер, Роман Віталійович; Сминтина, Валентин Андрійович; Бук, І.; Макак, М.; Гуров, А.; Конуп, Ігор Петрович; Гевелюк, Сергій АнатолійовичThe presented paper is devoted to investigation of structural and optical properties of titania nanofibers and the influence of Li doping on these properties. The investigated samples were prepared by the electrospinning method from polymeric solutions,containing TiO2 precursor,followed by a calcination procedure to obtain highly crystalline,pure inorganic nanofiber materials.The structural properties have been investigated by Scanning electron microscopy(SEM,FEI Nova)and X-ray diffractometry(XRD, Rigaku Ultima).The phase identification of the samples showed the anatase phase of TiO2.Linear dimensions of nanofibers were calculated.Optical properties were studied with use of UV—VIS spectrophotometer Shimadzu UV-1700 and photoluminescence(PL)setup(excitation with λ = 355 nm)in the range 350—1100 nm and 370—900 nm,correspondingly.The absorption edge of the samples was in the range of 395—410 nm.The PL maximums appeared at the range of 420—510 nm and 550—710 nm for both samples. The mechanisms of luminescence were discussed.Документ Photoluminescence and structural properties of nano-size CdS inclusions in porous glasses(Астропринт, 2007) Gevelyuk, Serhii A.; Doicho, Ihor K.; Mak, Vasyl T.; Zhukov, Serhii O.; Жуков, Сергій Олександрович; Жуков, Сергей АлександровичCadmium sulphide nanometer-formations in porous glass matrix are obtained. Results of electron-microscopic, XRD and EDS investigation of these formations are presented. The photoluminescence spectra of obtained samples are inves- tigated, and features of these spectra are explained.Документ Photoluminescence of tautomeric forms of nanoparticle ensembles of dyes based on the 4-valence stannum complexes in porous silica glass(Одесский национальный университете имени И. И. Мечникова, 2015) Doicho, Ihor K.; Gevelyuk, Serhii A.; Rysiakiewicz-Pasek, E.; Дойчо, Ігор Костянтинович; Гевелюк, Сергей Анатольевич; Ришякевич-Пасек, Е.; Дойчо, Игорь Константинович; Гевелюк, Сергій Анатолійович; Рысакеви-Пасек, Е.Luminescence of tautomeric forms of dyes based on the 4-valence stannum complexes was researched. Symmetry of photoluminescence spectra of different tautomeric forms relative to direction of reading of atom positions in the hydrazide fragment was found clockwise or anti clockwise. It was determined that the illumination of nanoparticle ensembles of dyes in A-type porous silica glass is always more intensive than in appropriate solution. It was shown that the luminescence intensity of tautomeric forms increases, if the substituent comes nearer to the coordination set irrespective of type and nature of substituent and type of coordination set. At the same time, change of illumination energy of tautomeric forms depends on both type and nature of substituent and coordination set. The results were explained by the development of inner surface of matrix and also by the features of atom disposition in dye molecule and by interaction between them.Документ Porous glasses with CDS inclusions luminescence kinetics peculiarities(Астропринт, 2009) Doicho, Ihor K.; Gevelyuk, Serhii A.; Ptashchenko, Oleksandr O.; Rysiakiewicz-Pasek, E.; Zhukov, Serhii O.; Дойчо, Игорь Константинович; Гевелюк, Сергей Анатольевич; Птащенко, Александр Александрович; Рысакевич-Пасек, Е.; Жуков, Сергей Александрович; Дойчо, Ігор Костянтинович; Гевелюк, Сергій Анатолійович; Птащенко, Олександр Олександрович; Ришякевич-Пасек, Е.; Жуков, Сергій ОлександровичThe kinetics of the luminescence of porous glass with CdS inclusions was studied at liquid nitrogen temperature. It is shown that the luminescence decay curves after excitation switching-off are different for different types of glasses. For CdS in matrices with small enough pores, a short-time “flash” of the luminescence was observed after the excitation turn off. Additional doping of the samples with Na2S enhanced the “flash”. The flash intensity and duration depended on the exciting photons energy. The effect is interpreted by thermo-optical excitation of electrons. Исследована кинетика фотолюминесценции пористого стекла с включениями CdS при температуре жидкого азота. Показано, что кривые спада фотолюминесценции после выключения возбуждения различны для различных типов стёкол. Для CdS в матрицах с достаточно малыми порами наблюдалась кратковременная вспышка люминесценции после выключения возбуждения. Дополнительное насыщение образцов Na2S усиливало указанную вспышку. Интенсивность и длительность вспышки зависела от энергии возбуждающих фотонов. Эффект объяснён термооптическим возбуждением электронов. Досліджено кінетику люмінесценції шпаристого скла із вкрапленнями CdS при температурі рідкого азоту. Продемонстровано, що криві спаду люмінесценції після вимкнення збудження неоднакові для різних типів скла. Для CdS в матрицях з достатньо малими порами спостерігався короткочасний спалах люмінесценції після вимкнення збудження. Додаткове насичення зразків Na2S підсилювало зазначений спалах. Інтенсивність і тривалість спалаху залежала від енергії збуджуючих фотонів. Ефект пояснено термооптичним збудженням електронів.Документ Substrate Crystallographic Orientation Effect on Photoluminescent Properties of Porous Silicon(Одеський національний університет імені І. І. Мечникова, 2005) Gevelyuk, Serhii A.; Doicho, Ihor K.; Mak, Vasyl T.; Soloshenko, Viktor I.; Lelechenko, V. P.; Zherditska, Y. R.Etching duration and anodic current density dependences of intensity and maximum position of the photoluminescence spectra of porous silicon layers obtained by anodization of silicon wafer are investigated. The sizes of silicon nanoclusters formed during the anodization procedure are estimated. It is shown that the dependence of formed clusters sizes on etching conditions for porous layers is different for various crystallographic orientations of the substrate. The model explaining this feature at various speeds of porous layer frontal advance deep into silicon substrate is offered. Presented results may be used for optimization of etching conditions in order to obtain the porous silicon layers having the preset parameters.Документ The Radiation Peculiarities of Nanoscale SnO2 in a Porous Matrix(2020) Gevelyuk, Serhii A.; Гевелюк, Сергій Анатолійович; Hrinevych, Viktor S.; Гріневич, Віктор Сергійович; Doicho, Ihor K.; Дойчо, Ігор Костянтинович; Lepikh, Yaroslav I.; Лепіх, Ярослав Ілліч; Лепих, Ярослав Ильич; Filevska, Liudmila M.; Філевська, Людмила МиколаївнаThe features of luminescent properties of an ensemble of tin dioxide nanoparticles created inside various types of porous silicate glass matrices under various thermosynthesis conditions are studied. It was demonstrated that the highest intensity of radiative recombination is inherent to the system formed in finely porous silicate glass with residual silica gel in the pores. Silica gel in this case prevents the aggregation of SnO2 nanoparticles. For the all types of matrix, the luminescence energy is less than the fundamental SnO2 energy gap, which may indicate a trap-like luminescence character of these systems. It was established an occurrence of at least two types of recombination centers – acceptors close to the valence band. The luminescence intensity varies depending on the content of the precursor in the initial solution to obtain samples. Its maximum is observed at 5-7 % tin chloride in the initial solution. The specified method of ensemble creation corresponds to the greatest width of the luminescence spectral lines, which is inherent to the intensity of radiative recombination. The smallest width of the spectral line corresponds to large concentrations close to those at which the SnCl4 alcohol solution becomes a strong glass adhesive. At these concentrations the solution already begins to glue the silica gel particles, freeing up space for the further formation of aggregations after the thermosynthesis reaction. In this case, the aggregation is intensive. In ensembles of SnO2 nanoparticles created in porous glass depleted in silica gel, nonradiative recombination predominates due to leakage channels through aggregations formed during thermosynthesis in the absence of an insulating substance. The study results can be used to create luminescent gas sensors based on SnO2.Документ TiO2-porphyrin nanostructures for amino acid detection(Одесский национальный университете имени И. И. Мечникова, 2013) Tereshchenko, Alla V.; Viter, Roman V.; Konup, Ihor P.; Ivanytsia, Volodymyr O.; Gevelyuk, Serhii A.; Ishkov, Yurii V.; Smyntyna, Valentyn A.; Терещенко, Алла Володимирівна; Витер, Роман Витальевич; Конуп, Игорь Петрович; Иваница, Владимир Алексеевич; Гевелюк, Сергей Анатольевич; Ишков, Юрий Васильевич; Смынтына, Валентин Андреевич; Вітер, Роман Віталійович; Конуп, Ігор Петрович; Іваниця, Володимир Олексійович; Ішков, Юрій Васильович; Сминтина, Валентин Андрійович; Терещенко, Алла ВладимировнаA novel optical sensor based on TiO2 nanoparticles for Valine (one of the twenty standard amino acids within proteins) detection has been developed. In the presented work, commercial TiO2nanoparticles (Sigma Aldrich, particle size 32 nm) were used as sensor templates. The sensitive layer was formed by a porphyrin coating on a TiO2 nanostructured surface. As a result, an amorphous layer between the TiO2 nanostructure and porphyrin was formed. Photoluminescence (PL) spectra were measured in the range of 370-900 nm before and after porphyrin application. Porphyrin adsorption led to a decrease of the main TiO2 peak at 510 nm and the emergence of an additional peak of high intensity at 700 nm. Absorption spectra (optical density vs. wavelenght, measured from 300 to 800 nm) also showed great changes; absorption edge shift and additional peaks appearing. Adsorption of amino acid resulted in a decrease of the intensity of the PL peak due to porphyrin and an increase of intensity of the TiO2 main PL peak. The interaction between the sensor surface and the amino acid leads to the formation of new complexes on the surface and results in a reduction of the optical activity of porphyrin. Sensitivity of the sensor with respect to different concentrations of Valine was calculated. The developed sensor can determine the consentration of Valine in the range of 0.04 to 0.16 mg/ml.