Персона: Самохвалов, Павел Сергеевич
Загружается...
Email Address
Birth Date
Организационные подразделения
Организационная единица
Инженерно-физический институт биомедицины
Цель ИФИБ и стратегия развития – это подготовка высококвалифицированных кадров на базе передовых исследований и разработок новых перспективных методов и материалов в области инженерно-физической биомедицины. Занятие лидерских позиций в биомедицинских технологиях XXI века и внедрение их в образовательный процесс, что отвечает решению практикоориентированной задачи мирового уровня – диагностике и терапии на клеточном уровне социально-значимых заболеваний человека.
Статус
Фамилия
Самохвалов
Имя
Павел Сергеевич
Имя
Результаты поиска
Теперь показываю 1 - 10 из 14
- ПубликацияТолько метаданныеOptical Properties of Quantum Dots with a Core–Multishell Structure(2019) Linkov, P.; Samokhvalov, P.; Vokhmintsev, K.; Zvaigzne, M.; Krivenkov, V. A.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2019, Pleiades Publishing, Inc. In the last decade, colloidal semiconductor nanocrystals (quantum dots) have been not only studied fundamentally but also applied in photovoltaics, optoelectronics, and biomedicine. Beginning with simple approaches to the deposition of protective shells, e.g., ZnS on CdSe cores, searches for ways to increase the quantum yield of photoluminescence of quantum dots have resulted now in the development of new types of quantum dots characterized not only by record high extinction coefficients but also by high photoluminescence quantum yields. In this work, the optical properties of core–multishell quantum dots have been analyzed. These quantum dots have been specially designed to reach the maximum possible localization of excited charge carriers inside luminescent cores, which makes it possible to reach a photoluminescence quantum yield close to 100%. Core–multishell quantum dot samples with a shell thickness of 3–7 monolayers have been fabricated. Changes in the characteristics of optical transitions in such quantum dots with an increase in the number of layers of the shell have been studied. The effect of the thickness of the shell on the optical properties of prepared quantum dots has been analyzed. In particular, analysis of photoluminescence lifetimes of such quantum dots has revealed a possible alternative mechanism of radiation of core–multishell quantum dots based on the slow charge carrier transfer from the excited outer layer of the CdS shell to the CdSe core.
- ПубликацияТолько метаданныеRemarkably enhanced photoelectrical efficiency of bacteriorhodopsin in quantum dot – Purple membrane complexes under two-photon excitation(2019) Krivenkov, V.; Samokhvalov, P.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2019 Elsevier B.V. The photosensitive protein bacteriorhodopsin (bR)has been shown to be a promising material for optoelectronic applications, but it cannot effectively absorb and utilize light energy in the near-infrared (NIR)region of the optical spectrum. Semiconductor quantum dots (QDs)have two-photon absorption cross-sections two orders of magnitude larger than those of bR and can effectively transfer the up-converted energy of two NIR photons to bR via the Förster resonance energy transfer (FRET). In this study, we have engineered a photoelectrochemical cell based on a hybrid material consisting of QDs and bR-containing purple membranes (PMs)of Halobacterium salinarum and demonstrated that this cell can generate an electrical signal under the two-photon laser excitation. We have shown that the efficiency of light conversion by the PM–QD hybrid material under two-photon excitation is up to 4.3 times higher than the efficiency of conversion by PMs alone. The QD integration into the bR-containing PMs significantly improves the bR capacity for utilizing light upon two-photon laser excitation, thus paving the way to the engineering of biologically inspired hybrid NIR nonlinear optoelectronic elements. The nonlinear nature of two-photon excitation may provide considerable advantages, such as a sharp sensitivity threshold and the possibility of precise three-dimensional location of excitation in holography and optical computing.
- ПубликацияТолько метаданныеConversion of Semiconductor Nanoparticles to Plasmonic Materials by Targeted Substitution of Surface-Bound Organic Ligands(2019) Samokhvalov, P. S.; Volodin, D. O.; Bozrova, S. V.; Dovzhenko, D. S.; Zvaigzne, M. A.; Lin'kov, P. A.; Nifontova, G. O.; Petrova, I. O.; Sukhanova, A. V.; Nabiev, I. R.; Самохвалов, Павел Сергеевич; Нифонтова, Галина Олеговна; Суханова, Алена Владимировна; Набиев, Игорь Руфаилович© 2019, Pleiades Publishing, Ltd.Abstract: Plasmonic nanoparticles have become a popularly accepted research tool in optoelectronics, photonics, and biomedical applications. The relatively recently appearing semiconductor plasmonic nanoparticles, as opposed to metal ones, are characterized by infrared plasmonic optical transitions and their application has a great future. In this work, the possibility of conversion of semiconductor (excitonic) fluorescence nanocrystals, i.e., quantum dots of the CuInS2 composition, to plasmonic nanoparticles by postsynthetic treatment without changes in the chemical composition of inorganic part of the nanocrystals was demonstrated for the first time ever.
- ПубликацияТолько метаданныеDirect Demonstration of Biexciton Quantum Yield Enhancement in an Individual Quantum Dot Coupled with Gold Nanoparticles in a Thin-film Hybrid Material(2019) Krivenkov, V.; Samokhvalov, P.; Nabiev, I.; Rakovich, Y.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович
- ПубликацияТолько метаданныеTwo-photon-activated light energy conversion in quantum dot-purple membrane hybrid material(2019) Krivenkov, V. A.; Samokhvalov, P. S.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичThe photosensitive protein bacteriorhodopsin (bR) has been shown to be a promising material for optoelectronic and photovoltaic applications, but it cannot effectively absorb and utilize light energy in the near-infrared (NIR) region of the optical spectrum. Semiconductor quantum dots (QDs) have two-photon absorption cross-sections two orders of magnitude larger than those of bR and can effectively transfer the up-converted energy of two NIR photons to bR via the Forster resonance energy transfer (FRET). In this study we fabricated a hybrid material in the form of an aqueous solution of electrostatically bound complexes of QDs and purple membranes (PMs) containing bR. Efficient FRET from QDs to bR was observed in these complexes under selective two-photon excitation of QDs. Then, we fabricated a photoelectrochemical cell operating in the NIR spectral region. Measurement of the photoelectrical signals from the cell containing pure PMs, or QD-PM hybrid material has shown that the light conversion in the QD-PM hybrid material with 3:1 bR-to-QD molar ratio is more efficient than in the material with 20:1 bR-to-QD molar ratio. The results of this study may extend the use of bioinspired hybrid materials in optoelectronics, holography, and bioenergetics under the conditions of nonlinear excitation.
- ПубликацияТолько метаданныеResonance energy transfer from quantum dots to bacteriorhodopsin affects the saturation of two-photon absorption under a pulsed femtosecond excitation(2019) Krivenkov, V. A.; Samokhvalov, P. S.; Chistyakov, A. A.; Nabiev, I.; Самохвалов, Павел Сергеевич; Чистяков, Александр Александрович; Набиев, Игорь РуфаиловичSemiconductor quantum dots (QDs) have high two-photon absorption cross-sections and long photoluminescence (PL) lifetimes, which make them a promising photosensitive part for fabrication of QD-based hybrid materials for two-photon bio-imaging, bio- and optoelectronics. In these areas, mode-locked femtosecond lasers are often used for two-photon excitation of QDs because of the high peak intensity of the laser pulse. However, the QD radiative lifetime usually exceeds the period between the laser pulses of such laser systems, which can affect the absorption and PL properties of QDs. In this work, we investigated the PL properties of CdSe/ZnS QDs under two-photon excitation. We have shown that using femtosecond laser excitation at a wavelength of 790 nm with a pulse repetition rate of 80 MHz and a peak intensity of more than 10 GW/cm(2), the two-photon absorption in QD is saturated. However if QDs were in complexes with purple membranes (PM) containing the photosensitive protein bacteriorhodopsin (bR), saturation was not observed up to an intensity of about 27 GW/cm(2). It was concluded that the difference in the saturation of two-photon absorption between QDs and QD-PM material is associated with the Forster resonance energy transfer from QD to bR and the corresponding shortening of the PL lifetime. The results obtained will allow to optimize the two-photon excitation regime of QD-PM nano-bio hybrid material which will expand the possible areas of its application in bio-imaging, bio- and optoelectronics.
- ПубликацияТолько метаданныеThe crucial role of surface ligands on the properties of thin CdSe/ZnS/CdS/ZnS QD-films for QDLEDs(2019) Zvaigzne, M. A.; Alexandrov, A. E.; Samokhvalov, P. S.; Самохвалов, Павел Сергеевич© 2019 SPIE.We report on the effects of surface organic ligands on the properties of CdSe/ZnS/CdS/ZnS quantum dot (QD) solutions and condensed films. Hexadecylamine, octylamine, hexadecanethiol, octanethiol, thiophenol and inorganic ZnCl2 were used as the QD surface ligands affecting their properties. Here, we analyze optical and electrical properties as well as surface quality of thin films fabricated from the QDs bearing different ligands on their surfaces. We have found that the use of thiol ligands results in QD-films with a uniform surface, sufficient quantum yield and resistance, thus approving their relevance for the use as electroluminescent layers in light emitting diodes.
- ПубликацияТолько метаданныеModification of multiphoton emission properties of single quantum dot due to the long-range coupling with plasmon nanoparticles in thin-film hybrid material(2019) Sanchez-Iglesias, A.; Grzelczak, M.; Krivenkov, V.; Samokhvalov, P.; Nabiev, I.; Rakovich, Y.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2019 SPIE.Semiconductor quantum dots (QDs) are known for their unique photophysical properties and, in particular, their ability to multiphoton emission caused by recombination of biexcitons. However, the luminescence quantum yield of biexciton states is relatively low due to the fast Auger non-radiative process. Plasmonic nanoparticles can significantly accelerate the radiative rate of QDs. In this study we demonstrate the distance-controlled enhancement of the biexciton emission of single CdSe/ZnS/CdS/ZnS QDs due to their coupling with gold nanorods. We explain this enhancement as the distancedependent trade-off between the energy transfer and the Purcell effect. Our findings constitute a reliable approach to managing the efficiency of multiphoton emission over a wide span of distances.
- ПубликацияТолько метаданныеNanophotonic tools based on the conjugates of nanoparticles with the single-domain antibodies for multi-photon micrometastases detection and ultrasensitive biochemical assays(2019) Ramos-Gomes, F.; Chames, P.; Baty, D.; Alves, F.; Sukhanova, A.; Samokhvalov, P.; Nabiev, I.; Суханова, Алена Владимировна; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2019 SPIE.Semiconductor quantum dots (QDs) are characterized by orders of magnitude higher multiphoton linear absorption cross-sections compared with conventional organic dyes. Combined with the QD photoluminescence quantum yield approaching 100%, this fact opens great prospects for the twophoton functional tumor imaging with QDs tagged with highly specific recognition molecules. Single-domain antibodies (sdAbs) or "nanobodies" derived from lamas are the smallest high-affinity recognition molecules, which may be tagged with the QDs thus permitting not only solid tumors multiphoton imaging but also rare disseminated cancer cells and micrometastases in the depth of the tissue to be detected. Additionally, unique photostability of QDs enables signal accumulation and significant enhancement of the sensitivity of routine biochemical and immunohistochemical assays to be obtained when the conjugates of QDs, instead of organic dyes, are used.
- ПубликацияТолько метаданныеGraphene - quantum dot hybrid nanostructures with controlled optical and photoelectric properties for solar cell applications(2019) Litvin, Alexander P.; Baranov, Alexander V.; Fedorov, Anatoly V.; Sokolov, Pavel M.; Zvaigzne, Maria A.; Krivenkov, Victor A.; Samokhvalov, Pavel S.; Nabiev, Igor R.; Соколов, Павел Михайлович; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичState-of-the-art research related to increasing the efficiency and reducing the cost of solar energy converters is analyzed. An approach to solving these issues is to introduce graphene and its derivatives into the photoactive layer of solar cells. These materials have record high charge carrier mobility at normal temperatures and low absorption cross-sections of solar radiation. The review considers chemical materials science methods and nanotechnology approaches to the design of 2D hybrid structures based on graphene and quantum dots. Examples of their most successful use in solar cells are given and promising areas of research and development in this field are formulated.