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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- 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.
- ПубликацияТолько метаданныеMicrofluidics and Nanofluidics in Strong Light–Matter Coupling Systems(2024) Granizo, E.; Kriukova, I.; Escudero-Villa, P.; Samokhvalov, P.; Nabiev, I.; Гранисо Роман, Эвелин Алехандра; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичThe combination of micro- or nanofluidics and strong light-matter coupling has gained much interest in the past decade, which has led to the development of advanced systems and devices with numerous potential applications in different fields, such as chemistry, biosensing, and material science. Strong light-matter coupling is achieved by placing a dipole (e.g., an atom or a molecule) into a confined electromagnetic field, with molecular transitions being in resonance with the field and the coupling strength exceeding the average dissipation rate. Despite intense research and encouraging results in this field, some challenges still need to be overcome, related to the fabrication of nano- and microscale optical cavities, stability, scaling up and production, sensitivity, signal-to-noise ratio, and real-time control and monitoring. The goal of this paper is to summarize recent developments in micro- and nanofluidic systems employing strong light-matter coupling. An overview of various methods and techniques used to achieve strong light-matter coupling in micro- or nanofluidic systems is presented, preceded by a brief outline of the fundamentals of strong light-matter coupling and optofluidics operating in the strong coupling regime. The potential applications of these integrated systems in sensing, optofluidics, and quantum technologies are explored. The challenges and prospects in this rapidly developing field are discussed.
- ПубликацияТолько метаданныеDetermination of the Single-Exciton Two-Photon Absorption Cross Sections of Semiconductor Nanocrystals through the Measurement of Saturation of Their Two-Photon-Excited Photoluminescence(2020) Karaulov, A.; Krivenkov, V.; Samokhvalov, P.; Dyagileva, D.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2020 American Chemical Society.Conventional approaches to the determination of the two-photon absorption cross-section (TPACS) of fluorescent semiconductor nanocrystals, including quantum dots (QDs) and nanoplatelets (NPLs), cannot be applied to samples with unknown concentrations and low optical densities and may be inaccurate in the case of multiexciton nanocrystal excitation. Here, we have studied the two-photon-excited photoluminescence saturation in QD and NPL samples and propose a novel technique for determining of their TPACS from the parameters of this process. The technique allows the measurement of the TPACSs of single exciton states in the samples of unknown concentration, as well as in thin films with ultralow optical densities. The calculated values agreed with the results obtained by conventional methods. The new technique paves new ways to studying small amounts of fluorescent nanocrystals of unknown quantity under two-photon excitation.
- ПубликацияТолько метаданныеEffect of Spectral Overlap and Separation Distance on Exciton and Biexciton Quantum Yields and Radiative and Nonradiative Recombination Rates in Quantum Dots Near Plasmon Nanoparticles(2020) Krivenkov, V.; Dyagileva, D.; Samokhvalov, P.; Nabiev, I.; Rakovich, Y.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimEfficient biexciton (BX) photoluminescence (PL) from quantum dots (QDs) paves the way to the generation of entangled photons and related applications. However, the quantum yield (QY) of BX PL is much lower than that for single excitons (EX) due to efficient Auger-like recombination. In the vicinity of plasmon nanoparticles, the recombination rates of EX and BX may be affected by the Purcell effect, fluorescence quenching, and the excitation rate enhancement. Here, the effect of the plasmon resonance spectral position on the EX and BX PL is experimentally studied in two cases: when the plasmon band overlaps with the excitation wavelength and when it coincides with the QDs PL band. In the first case, the EX and BX excitation efficiencies are significantly increased but the EX QY reduced. As a result, the BX-to-EX QY ratio is higher than 1 at plasmon–exciton systems separations shorter than 40 nm. In the second case, the radiative recombination rates are enhanced by several orders of magnitude, which led to an increase in BX QY over distances of up to 90 nm. Finally, these two effects are obtained in the same hybrid structure, with the resultant increase in both excitation efficiency and QY of BX PL.
- 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.