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 Руфаилович

Controlling 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

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.

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.

2021, Rakovich, Y. P., Krivenkov, V., Samokhvalov, P., Nabiev, I., Самохвалов, Павел Сергеевич, Набиев, Игорь Руфаилович

© 2021 American Chemical Society.Remote control of the pH of the medium is an important task for many applications in chemistry, medicine, and biology. Remote control of the pH using light is an intelligent and cost-effective approach. The nanoscale plasmon-exciton (plexciton) light-matter coupling is a physical phenomenon that provokes strong changes in the optical properties of the original plasmon and exciton bands, resulting in a transparency dip in the initial plasmon spectrum and formation of two hybrid plexciton side bands separated by the Rabi splitting energy. The plexciton coupling strength is unaffected by the temperature and light irradiation stressors but strongly depends on the transition dipole moment of the exciton material. Here, we show that the optical parameters of the plexciton coupling can be controlled by varying the pH of the medium. To demonstrate this, we obtained resonant light-matter coupling between the plasmon band of silver nanoplates and the J-band of J-aggregates with a Rabi splitting energy of up to 450 meV and found that both the extinction dip and the splitting energy are strongly affected by variation of pH from 2.5 to 11. We explain this effect by a change in the structure of the J-aggregates and reduction of the J-band intensity, which is confirmed by numerical simulation.

2020, Dovzhenko, D., Krivenkov, V., Kriukova, I., Samokhvalov, P., Nabiev, I., Крюкова, Ирина Сергеевна, Самохвалов, Павел Сергеевич, Набиев, Игорь Руфаилович

Photoluminescence (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

2016, Sizova, S. V., Oleinikov, V. A., Bouchonville, N., Molinari, M., Samokhvalov, P. S., Sukhanova, A., Nabiev, I., Суханова, Алена Владимировна, Набиев, Игорь Руфаилович, Олейников, Владимир Александрович

The integration of novel nanomaterials with highly functional biological molecules has numerous advanced applications, including optoelectronics, biosensing, imaging, and energy harvesting. This review summarizes recent progress in understanding the mechanisms of energy transfer between semiconductor nanocrystal (so-called quantum dots [QDs]) and photosensitive proteins in heterostructures, such as hybrids of semiconductor nanocrystals with purple membranes containing bacteriorhodopsin (bR) or with photosynthetic reaction centers (RCs). Understanding of these mechanisms should enable prediction of the possible ways to improve the biological function of biomolecules by means of their assembling with QDs and develop novel functional materials with controlled photonic properties and applications. The possible mechanisms of energy transfer from QDs to photochromic biomolecules are discussed and correlated with experimental data. The principles of hybrid structures engineering, donor/acceptor parameters affecting both energy transfer efficiency and biological function, and functionality of these hybrid structures are described. New nanobiohybrid materials are shown to have advanced implications for optoelectronics, photonics, and photovoltaics due to the ability of nanocomponents of these materials for efficient energy harvesting, conversion, and transfer of additional energy to Biosystems, thus making them working more efficiently.

2019, Dovzhenko, D., Vaskan, I., Kriukova, I., Rakovich, Y., Nabiev, I., Крюкова, Ирина Сергеевна, Набиев, Игорь Руфаилович

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 Руфаилович

The 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.

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.

2019, Krivenkov, V., Samokhvalov, P., Nabiev, I., Rakovich, Y., Самохвалов, Павел Сергеевич, Набиев, Игорь Руфаилович