Персона: Самохвалов, Павел Сергеевич
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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.
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- ПубликацияОткрытый доступStrong increase in the effective two-photon absorption cross-section of excitons in quantum dots due to the nonlinear interaction with localized plasmons in gold nanorods(2021) Sanchez-Iglesias, A.; Grzelczak, M.; Rakovich, Y.; Krivenkov, V.; Samokhvalov, P.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2021 The Royal Society of Chemistry.Excitons in semiconductor quantum dots (QDs) feature high values of the two-photon absorption cross-sections (TPACSs), enabling applications of two-photon-excited photoluminescence (TPE PL) of QDs in biosensing and nonlinear optoelectronics. However, efficient TPE PL of QDs requires high-intensity laser fields, which limits these applications. There are two possible ways to increase the TPE PL of QDs: by increasing their photoluminescence quantum yield (PLQY) or by further increasing the TPACS. Plasmonic nanoparticles (PNPs) may act as open nanocavities for increasing the PLQY via the Purcell effect, but this enhancement is strictly limited by the maximum possible PLQY value of 100%. Here we directly investigated the effect of PNPs on the effective TPACS of excitons in QDs. We have found that effective TPACS of excitons in a QD-PMMA thin film can be increased by a factor of up to 12 near the linearly excited gold nanorods (GNRs). Using gold nanospheres (GNSs), in which plasmons cannot be excited in the infrared range, as a control system, we have shown that, although both GNSs and GNRs increase the recombination rate of excitons, the TPACS is increased only in the case of GNRs. We believe that the observed effect of TPACS enhancement is a result of the nonlinear interaction of the plasmons in GNRs with excitons in QDs, which we have supported by numerical simulations. The results show the way to the rational design of the spectral features of plasmon-exciton hybrids for using them in biosensing and nonlinear optoelectronics.
- ПубликацияОткрытый доступSynergy of Excitation Enhancement and the Purcell Effect for Strong Photoluminescence Enhancement in a Thin-Film Hybrid Structure Based on Quantum Dots and Plasmon Nanoparticles(2020) Rakovich, Y. P.; Krivenkov, V.; Samokhvalov, P.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичReliable control of spontaneous radiation from quantum emitters, such as quantum dots (QDs), is an extremely important problem in quantum science, nanophotonics, and engineering. The QD photoluminescence (PL) may be enhanced near plasmon nanoparticles because of excitation field enhancement or the Purcell effect. However, both of these effects have their specific limitations. The excitation enhancement is usually accompanied by a decrease in the PL quantum yield (QY) due to the plasmon-induced energy transfer, and the Purcell effect cannot significantly enhance the PL of QDs with an initially high QY because of the obvious limitation of the QY by the value of 100%. Here, we have shown that the synergistic combination of excitation enhancement caused by silver nanospheres and the Purcell effect caused by silver nanoplates in the same QD-in-polymer hybrid thin-film nanostructure permits simultaneous increases in the radiative and excitation rates to be obtained. This overcomes the limitations of each individual effect and yields a synergistic PL increase (+1320%) greater than the sum of the PL enhancements determined by each effect alone (+70% and +360%).
- ПубликацияОткрытый доступHybrid fluorescent liquid crystalline composites: Directed assembly of quantum dots in liquid crystalline block copolymer matrices(2020) Bugakov, M.; Abdullaeva, S.; Abramchuk, S.; Shibaev, V.; Samokhvalov, P.; Самохвалов, Павел СергеевичThis journal is © 2020 The Royal Society of Chemistry.Hybrid fluorescent liquid crystalline (LC) composites containing inorganic quantum dots (QDs) are promising materials for many applications in optics, nanophotonics and display technology, combining the superior emission capability of QDs with the externally controllable optical properties of LCs. In this work, we propose the hybrid LC composites that were obtained by embedding CdSe/ZnS QDs into a series of host LC block copolymers of different architectures by means of a two-stage ligand exchange procedure. The ABA/BAB triblock copolymers and AB diblock copolymers with different polymerization degrees are composed of nematogenic phenyl benzoate acrylic monomer units and poly(4-vinylpyridine) blocks, which are capable of binding to the QD surface. Our results clearly show that the spatial distribution of QDs within composite films as well as the formation of QD aggregates can be programed by varying the structure of the host block copolymer. The obtained composites form a nematic LC phase, with isotropization temperatures being close to those of the initial host block copolymers. In addition, the influence of the molecular architecture of the host block copolymers on fluorescence properties of the obtained composites is considered. The described strategy for the QD assembly should provide a robust and conventional route for the design of highly ordered hierarchical hybrid materials for many practical applications.
- ПубликацияОткрытый доступAl-, Ga-, Mg-, or Li-doped zinc oxide nanoparticles as electron transport layers for quantum dot light-emitting diodes(2020) Alexandrov, A.; Zvaigzne, M. A.; Lypenko, D.; Nabiev, I.; Samokhvalov, P.; Лыпенко, Дмитрий Александрович; Набиев, Игорь Руфаилович; Самохвалов, Павел Сергеевич© 2020, The Author(s).Colloidal quantum dots and other semiconductor nanocrystals are essential components of next-generation lighting and display devices. Due to their easily tunable and narrow emission band and near-unity fluorescence quantum yield, they allow cost-efficient fabrication of bright, pure-color and wide-gamut light emitting diodes (LEDs) and displays. A critical improvement in the quantum dot LED (QLED) technology was achieved when zinc oxide nanoparticles (NPs) were first introduced as an electron transport layer (ETL) material, which tremendously enhanced the device brightness and current efficiency due to the high mobility of electrons in ZnO and favorable alignment of its energy bands. During the next decade, the strategy of ZnO NP doping allowed the fabrication of QLEDs with a brightness of about 200 000 cd/m2 and current efficiency over 60 cd/A. On the other hand, the known ZnO doping approaches rely on a very fine tuning of the energy levels of the ZnO NP conduction band minimum; hence, selection of the appropriate dopant that would ensure the best device characteristics is often ambiguous. Here we address this problem via detailed comparison of QLEDs whose ETLs are formed by a set of ZnO NPs doped with Al, Ga, Mg, or Li. Although magnesium-doped ZnO NPs are the most common ETL material used in recently designed QLEDs, our experiments have shown that their aluminum-doped counterparts ensure better device performance in terms of brightness, current efficiency and turn-on voltage. These findings allow us to suggest ZnO NPs doped with Al as the best ETL material to be used in future QLEDs.
- ПубликацияТолько метаданныеMachine learning–assisted colloidal synthesis: A review(2024) Gulevich, D. G.; Nabiev, I. R.; Samokhvalov, P. S.; Гулевич, Даяна Галимовна; Набиев, Игорь Руфаилович; Самохвалов, Павел СергеевичArtificial intelligence (AI) technologies, including machine learning and deep learning, have become ingrained in both everyday life and in scientific research. In chemistry, these algorithms are most commonly used for the development of new materials and drugs, recognition of microscopy images, and analysis of spectral data. Finding relationships between the parameters of chemical synthesis and the properties of the resultant materials is often challenging because of the large number of variations of the temperature and time of synthesis, the chemical composition and ratio of precursors, etc. Applying machine and deep learning to the organization of chemical experiments will considerably reduce the empiricism issues in chemical research. Colloidal nanomaterials, whose morphology, size, and phase composition are influenced directly not only by the synthesis conditions, but the reagents or solvents purity and other indistinct factors are highly demanded in optoelectronics, catalysis, biological imaging, and sensing applications. In recent years, AI methods have been increasingly used for determining the key factors of synthesis and selecting the optimal reaction conditions for obtaining nanomaterials with precisely controlled and reproducible characteristics. The purpose of this review is to analyze the current progress in the AI-assisted optimization of the most common methods of production of colloidal nanomaterials, including colloidal and hydrothermal syntheses, chemical reduction, and synthesis in flow reactors.
- 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 метаданныеEnhanced fluorescence emission of a single quantum dot in a porous silicon photonic crystal-plasmonic hybrid resonator(2024) Granizo, E.; Kriukova, I.; Samokhvalov, P.; Nabiev, I.; Гранисо Роман, Эвелин Алехандра; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичAbstract Currently, much interest is attracted to investigating the potential of hybrid systems that exhibit plasmon-induced photoluminescence (PL) enhancement of quantum emitters in terms of optoelectronics and biosensing applications. The implementation of these systems based on photonic microcavities offers benefits due to a stronger localization of the field within the resonant cavity. Porous silicon is one of interesting materials for engineering such microcavities thanks to the simplicity of its fabrication and the possibility to embed emitters from the solution into a ready-made resonator. In this theoretical study, the fluorescence enhancement of a quantum dot (QD) in a hybrid system based on a porous silicon microcavity (pSiMC) and silver nanoplatelets (AgNPs) was investigated using finite element method (FEM) numerical simulations. For this purpose, infinite arrays were simulated by using a periodic unit cell. The pSiMC was designed as two Ћ? /4 distributed Bragg reflectors with alternating refractive indices and a cavity layer of a double thickness between them. For comparison, simulations were also performed for an AgNP and a QD in a reference monolayer with a constant refractive index without a microcavity structure. The results show QD fluorescence enhancement in the AgNP/pSiMC hybrid system, mainly due to the higher excitation rate.
- ПубликацияТолько метаданныеCavity-enhanced photoluminescence of semiconductor quantum dot thin films under two-photon excitation(2021) Dovzhenko, D.; Saanchez-Iglesias, A.; Grzelczak, M.; Rakovich, Y.; Krivenkov, V.; Kriukova, I.; Samokhvalov, P.; Nabiev, I.; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2021 SPIE.Semiconductor quantum dots (QDs) feature high values of the two-photon absorption (TPA) cross-sections, enabling their applications in biosensing and nonlinear optoelectronics. However, the efficient QD photoluminescence (PL) intensity caused by TPA requires high-intensity laser excitation which hinders these applications. Placing the QDs in the micro- or nanocavities leads to a change in their PL properties. Particularly, near plasmon nanoparticles (open nanocavities) the local field may be enhanced by the localized plasmons, which will lead to an increase of the TPA efficiency. Alternatively, placing QDs in a photonic crystal may boost an increase of their PL quantum yield due to the Purcell effect and also increase their PL intensity at the photonic mode wavelength due to the redistribution of the density of photonic states. In this study, we have fabricated thin-film hybrid materials based on QDs placed near plasmonic nanoparticles or in the photonic crystal. We have demonstrated a 4.3-fold increase of the radiative recombination rate of QDs in the photonic crystal cavity under the two-photon excitation, resulting in the increase of the PL quantum yield. In turn, the coating of the QDs films with the gold nanorods led to the 12-fold increase in TPA at the maximum of the plasmon spectrum. Our results pave the way to a strong increase of the PL efficiency of the QDs under two-photon excitation for their applications in biosensing and nonlinear optoelectronics.
- ПубликацияТолько метаданныеConjugates of ultrasmall quantum dots and acridine derivatives as prospective nanoprobes for intracellular investigations(2021) Laronze-Cochard, M.; Sapi, J.; Karaulov, A.; Linkov, P.; Samokhvalov, P.; Baryshnikova, M.; Nabiev, I.; Самохвалов, Павел Сергеевич; Барышникова, Мария Анатольевна; Набиев, Игорь Руфаилович© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Designing nanoprobes in which quantum dots (QDs) are used as photoluminescent labels is an especially promising line of research due to their possible medical applications ranging from disease diagnosis to drug delivery. In spite of the significant progress made in designing such nanoprobes, the properties of their individual components, i.e., photoluminescent QDs, vectorization moieties, and pharmacological agents, still require further optimization to enhance the efficiency of diagnostic or therapeutic procedures. Here, we have developed a method of engineering compact multifunctional nanoprobes based on functional components with optimized properties: bright photoluminescence of CdSe/ZnS (core/shell) QDs, a compact and effective antitumor agent (an acridine derivative), and direct conjugation of the components via electrostatic interaction, which provides a final hydrodynamic diameter of nanoprobes smaller than 15 nm. Due to the possibility of conjugating various biomolecules with hydroxyl and carboxyl moieties to QDs, the method represents a versatile approach to the biomarker-recognizing molecule imaging of the delivery of the active substance as part of compact nanoprobes.
- 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.