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 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 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 метаданныеEnhancement of spontaneous emission of semiconductor quantum dots inside one-dimensional porous silicon photonic crystals(2020) Dovzhenko, D.; Martynov, I.; Samokhvalov, P.; Osipov, E.; Lednev, M.; Chistyakov, A.; Nabiev, I.; Мартынов, Игорь Леонидович; Самохвалов, Павел Сергеевич; Осипов, Евгений Валерьевич; Чистяков, Александр Александрович; Набиев, Игорь РуфаиловичControlling spontaneous emission by modifying the local electromagnetic environment is of great interest for applications in optoelectronics, biosensing and energy harvesting. Although the development of devices based on one-dimensional porous silicon photonic crystals with embedded luminophores is a promising approach for applications, the efficiency of the embedded luminophores remains a key challenge because of the strong quenching of the emission due to the contact of the luminophores with the surface of porous silicon preventing the observation of interesting light-matter coupling effects. Here, we experimentally demonstrate an increase in the quantum dot (QD) spontaneous emission rate inside a porous silicon microcavity and almost an order of magnitude enhancement of QD photoluminescence intensity in the weak light-matter coupling regime. Furthermore, we have demonstrated drastic alteration of the QD spontaneous emission at the edge of the photonic band gap in porous silicon distributed Bragg reflectors and proved its dependence on the change in the density of photonic states. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
- ПубликацияТолько метаданныеEnhanced spontaneous emission from two-photon-pumped quantum dots in a porous silicon microcavity(2020) Dovzhenko, D.; Krivenkov, V.; Kriukova, I.; Samokhvalov, P.; Nabiev, I.; Крюкова, Ирина Сергеевна; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичPhotoluminescence (PL)-based sensing techniques have been significantly developed in practice due to their key advantages in terms of sensitivity and versatility of the approach. Recently, various nanostructured and hybrid materials have been used to improve the PL quantum yield and the spectral resolution. The near-infrared (NIR) fluorescence excitation has attracted much attention because it offers deep tissue penetration and it avoids the autofluorescence of the biological samples. In our study, we have shown both spectral and temporal PL modifications under two-photon excitation of quantum dots (QDs) placed in one-dimensional porous silicon photonic crystal (PhC) microcavities. We have demonstrated an up-to-4.3-fold Purcell enhancement of the radiative relaxation rate under two-photon excitation. The data show that the use of porous silicon PhC microcavities operating in the weak coupling regime permits the enhancement of the PL quantum yield of QDs under two-photon excitation, thus extending the limits of their biosensing applications in the NIR region of the optical spectrum. (C) 2020 Optical Society of America
- ПубликацияТолько метаданныеControlling Charge Transfer from Quantum Dots to Polyelectrolyte Layers Extends Prospective Applications of Magneto-Optical Microcapsules(2020) Efimov, A. E.; Agapova, O. I.; Agapov, I. I.; Korostylev, E.; Nifontova, G.; Krivenkov, V.; Zvaigzne, M.; Samokhvalov, P.; Nabiev, I.; Нифонтова, Галина Олеговна; Самохвалов, Павел Сергеевич; Набиев, Игорь РуфаиловичThe layer-by-layer (LbL) deposition approach allows combined incorporation of fluorescent, magnetic, and plasmonic nanoparticles into the shell of polyelectrolyte microcapsules to obtain stimulus-responsive systems whose imaging and drug release functions can be triggered by external stimuli. The combined use of fluorescent quantum dots (QDs) and magnetic nanoparticles (MNPs) yields magnetic-field-driven imaging tools that can be tracked and imaged even deep in tissue when the appropriate type of QDs and wavelength of their excitation are used. QDs are excellent photonic labels for microcapsule encoding due to their close-to-unity photoluminescence (PL) quantum yields, narrow PL emission bands, and tremendous one- and two-photon extinction coefficients. However, the presence of MNPs and electrically charged polyelectrolyte molecules used for the LbL fabrication of magneto-optical microcapsules provokes alterations of the QD optical properties because of the photoinduced charge and energy transfer resulting in QD photodarkening or photobrightening. These lead to variation of the microcapsule PL signal under illumination, which hampers their tracking and quantitative analysis in cells and tissues. Here, we have studied the effects of the structure and spatial arrangement of the nanoparticles within the microcapsule polyelectrolyte shell, the total shell thickness, and the shell surface charge on their PL properties under continuous illumination. The roles of the charge transfer and its main driving forces in the stability of the microcapsules PL signal have been established, and the design of the microcapsules dually encoded with QDs and MNPs providing the strongest and most stable PL has been determined. Controlling the energy transfer from the QDs and MNPs and the charge transfer from QDs to polyelectrolyte layers in the engineering of magneto-optical microcapsules with a bright and stable PL signal extends their applications to long-lasting quantitative fluorescence imaging.
- ПубликацияТолько метаданныеAbsolute two-photon absorption cross-sections of single-exciton states in semiconductor nanocrystals(2020) Krivenkov, V.; Samokhvalov, P.; Dyagileva, D.; Nabiev, I.; Самохвалов, Павел Сергеевич; Набиев, Игорь Руфаилович© 2020 SPIE.Semiconductor nanocrystals (SNCs), in particular, quantum dots (QDs) and nanoplatelets (NPLs), have orders of magnitude higher two-photon absorption cross-sections (TPACS) than organic dyes, what paves the way to their advanced applications in bioimaging, sensing, and optoelectronics. Traditionally, z-scan and two-photon photoluminescence (PL) excitation spectroscopy are used to determine the TPACS values. The main disadvantage of both methods is the necessity to know the exact sample concentration. In this study, we describe an approach to the TPACS determination from the analysis of two-photon-excited (TPE) PL saturation in CdSe(core)/ZnS/CdS/ZnS(multishell) QDs and CdSe NPLs. The results obtained for NPLs using developed approach are significantly smaller than those obtained by the z-scan method and are close to the values obtained for QDs. We assume that this discrepancy occurs due to the fact, that unlike the z-scan technique, the TPE PL saturation method measures the TPACS only for single-exciton states because of the low PL quantum yields of multiexciton states. Therefore, there is no need to know the concentration, which eliminates the corresponding estimation error. Thus, the measurement of TPE PL saturation in SNCs makes it possible to determine the absolute values of the TPACS of single-exciton states, which are more informative for applications of TPE PL than the TPACS of mixed multiexciton states.