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
17 results
Результаты поиска
Теперь показываю 1 - 10 из 17
- ПубликацияТолько метаданныеExperimental and theoretical study of a flow photoreactor operating in the strong light-matter coupling regime(2024) Granizo, E. A.; Kriukova, I. S.; Samokhvalov, P. S.; Nabiec, I. R.; Гранисо Роман, Эвелин Алехандра; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович
- ПубликацияТолько метаданныеHybrid fluorescent cholesteric materials with controllable light emission containing CdSe/ZnS quantum dots stabilized by liquid crystalline block copolymer(2021) Bugakov, M. A.; Shibaev, V. P.; Boiko, N. I.; Samokhvalov, P. S.; Самохвалов, Павел Сергеевич© 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementHybrid fluorescent cholesteric liquid crystalline (CLC) materials are representatives of “smart” soft matter, and are characterized by light emission that can be flexibly controlled by various external stimuli. This fact is due to the many possibilities for potential applications in the fields of photonics and optics stimulating design, and study of this type of hybrid materials. Here, we report on the optical and fluorescence properties of the hybrid CLC material based on a low-molecular-weight CLC matrix and CdSe/ZnS quantum dots (QDs) stabilized by LC diblock copolymers. The hybrid CLC material is characterized by the cholesteric phase in a wide temperature range, the high loading of QDs, and no QD aggregation. We demonstrate that the cholesteric stop band alters characteristics of the QD emission due to the resonance effect. This makes the polarization state and wavelength of the QD emission thermo- and angle-dependent. This work provides a way for the design of a wide range of field-controllable photonic devices for various applications.
- ПубликацияТолько метаданныеWeak Coupling between Light and Matter in Photonic Crystals Based on Porous Silicon Responsible for the Enhancement of Fluorescence of Quantum Dots under Two-Photon Excitation(2020) Kriukova, I. S.; Krivenkov, V. A.; Samokhvalov, P. S.; Nabiev, I. R.; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2020, Pleiades Publishing, Inc.The development of optical and, in particular, photoluminescent sensors is currently becoming more and more significant because of their universality, selectivity, and high sensitivity ensuring their wide applications in practice. The efficiency of existing photoluminescent sensors can be increased by using photoluminescent nanomaterials and hybrid nanostructures. For biological applications of photoluminescent sensors, it is extremely relevant to excite photoluminescence in the near infrared spectral range, which allows excluding the effect of autofluorescence of biomolecules and ensuring a deeper penetration of radiation into biological tissues. In this work, it has been studied how the spectral and kinetic parameters of photoluminescence change under two-photon excitation of semiconductor quantum dots incorporated into a one-dimensional photonic crystal, a porous silicon microcavity. It has been shown that the formation of a weak coupling between an exciton transition in quantum dots and an eigenmode of the microcavity enhances the photoluminescence of quantum dots. It is important that quantum dots placed in the porous silicon matrix hold a sufficiently large cross section for two-photon absorption, which makes it possible to efficiently excite their exciton states up to saturation without reaching powers leading to the photothermic destruction of the structure of porous silicon and to the disappearance of the weak coupling effect. It has been demonstrated that the radiative recombination rate under the two-photon excitation of the system consisting of quantum dots and the microcavity increases by a factor of 4.3; it has been shown that this increase is due to the Purcell effect. Thus, fabricated microcavities based on 1D porous silicon crystals allow controlling the quantum yield of photoluminescence of quantum dots under two-photon excitation, which opens prospects for the development of new photoluminescent sensors based on quantum dots operating in the near infrared spectral range.
- ПубликацияТолько метаданныеLong-range coupling of individual quantum dots with plasmonic nanoparticles in a thin-film hybrid material(2020) Rakovich, Y. P.; Dyagileva, D. V.; Krivenkov, V. A.; Samokhvalov, P. S.; Nabiev, I. R.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2020 SPIE.Semiconductor quantum dots (QDs) are widely used in photovoltaic and optoelectronic devices due to their unique optical properties. Photoluminescence (PL) properties of QDs can be significantly improved by their electromagnetic coupling with plasmonic nanoparticles (PNPs). The excitation of resonant localized plasmon modes leads to the enhancement of the density of photon states and increase of electromagnetic field near the surface of PNPs, what boosts the acceleration of the exciton radiative decay, known as the Purcell effect. To study the dependence of the degree of acceleration of radiative decay rate (Purcell factor) on the distance between QDs and PNPs, we fabricated thin-film hybrid structures based on CdSe(core)/ZnS/CdS/ZnS(multishell) QDs and silver or gold PNPs with a controllable distance between these components. The change in the radiative decay rate of excitons was calculated from the PL intensities and lifetimes before and after the deposition of PNPs on top of the QD thin film covered by a poly(methyl methacrylate) (PMMA) spacer. For both PNP types, the PL lifetime of underlying QDs decreased, whereas the PL intensity of the latter decreased only slightly for gold PNPs and even increased for silver PNPs. This indicates the acceleration of QDs radiative decay (Purcell effect) mediated by exciton-plasmon interaction. The Purcell factor was higher for silver PNPs than that for gold PNPs, what can be explained by the better spectral overlap between the QDs PL band and silver PNPs absorbance and the absence of interband absorption in silver at the wavelength of QDs PL. The results of this study provide better understanding of the Purcell effects in hybrid materials based on QDs and PNPs.
- 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 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 метаданныеLabel-Free Detection of the Receptor-Binding Domain of the SARS-CoV-2 Spike Glycoprotein at Physiologically Relevant Concentrations Using Surface-Enhanced Raman Spectroscopy(2022) Sarychev, A. K.; Sukhanova, A.; Ivanov, A. V.; Bykov, I. V.; Bakholdin, N. V.; Vasina, D. V.; Gushchin, V. A.; Tkachuk, A. P.; Nifontova, G.; Samokhvalov, P. S.; Karaulov, A.; Nabiev, I.; Нифонтова, Галина Олеговна; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичSurface-enhanced Raman scattering (SERS) spectroscopy is a surface-or cavity-enhanced variant of Raman scattering spectroscopy that allows the detection of analytes with a sensitivity down to single molecules. This method involves the use of SERS-active surfaces or cavities capable of concentrating incident radiation into small mode volumes containing the analyte. Here, we have engineered an ultranarrow metal–dielectric nano-cavity out of a film of the receptor-binding domain (RBD) of SARS-CoV-2 spike (S) glycoprotein and a silver surface, held together by interaction between reduced protein sulfhydryl groups and silver. The concentration of light in this nano-cavity allows the label-free recording of the characteristic Raman spectra of protein samples smaller than 1 pg. This is sufficient for the ultrasensitive detection of viral protein antigens at physiologically relevant levels. Moreover, the protein SERS signal can be increased by several orders of magnitude by coating the RBD film with a nanometer-thick silver shell, thereby raising the cavity Q-factor. This ensures a sub-femtogram sensitivity of the viral antigen detection. A simple theoretical model ex-plaining the observed additional enhancement of the SERS signal from the silver-coated protein is proposed. Our study is the first to obtain the characteristic Raman and SERS spectra of the RBD of S glycoprotein, the key SARS-CoV-2 viral antigen, directly, without the use of Raman-reporter mol-ecules. Thus, our approach allows label-free recording of the characteristic spectra of viral antigens at concentrations orders of magnitude lower than those required for detecting the whole virus in biological media. This makes it possible to develop a high-performance optical detection method and conformational analysis of the pathogen and its variants. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
- 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 метаданныеIncreasing the brightness and efficiency of quantum dot light-emitting diodes by optimizing the PMMA electron-blocking layer(2022) Alexandrov, A. E.; Lypenko, D. A.; Nabievc, I.; Tkach, A. A.; Saunina, A. Y.; Nikitenko, V. R.; Samokhvalov, P. S.; Саунина, Анна Юрьевна; Никитенко, Владимир Роленович; Самохвалов, Павел Сергеевич© 2022 SPIE. All rights reserved.Quantum dots (QDs) are promising materials for advanced light-emitting diodes (LEDs). Their high thermo- and photostabilities compared to the currently used organic materials allow achieving a greater brightness due to a higher current density. However, the imbalance of the carrier injection/transport rates is one of the weakest points of QD-based LEDs (QDLEDs), because excess charges accumulated in the emitting layer quench light emission due to various nonradiative processes. The imbalance of charge carrier transport rates in QDLEDs is related to the high potential barrier for hole injection into the QD layer, accompanied by a greater mobility of negative charges in the electron transport layer. To solve this problem, an electron-blocking layer (EBL, made, e.g., of PMMA) can be introduced, which makes it possible to control the flow of electrons into the emitting layer. Here, we have theoretically and experimentally investigated the dependence of the luminosity and current efficiency of an ITO/PEDOT:PSS/poly- TPD/PVK/QDs/PMMA/ZnO/Al multilayer QDLED on the thickness of its EBL. For this purpose, a series of devices was fabricated with the PMMA layer thickness ranging from 0.13 to 3.1 nm. By tuning this thickness, we have obtained a device with a brightness exceeding that of the control device without an EBL by a factor of four, current efficiency increased by almost an order of magnitude, and turn-on voltage lowered by about 1 V. Furthermore, we have developed a theoretical model of QDLEDs under study, which is consistent with their measured current-voltage characteristics. Using our model, we show that the brightness of the device can be significantly increased by an increase in the thickness of the polymer hole-transport layer (HTL) compared with the QD layer. Therefore, it can be concluded that fine-tuning the thicknesses of both hole- and electron transport layers of a QDLED is a promising strategy to improve charge carrier balance and thereby achieve efficient light emission.