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Никитенко, Владимир Роленович

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Институт нанотехнологий в электронике, спинтронике и фотонике

Институт ИНТЭЛ занимается научной деятельностью и подготовкой специалистов в области исследования физических принципов, проектирования и разработки технологий создания компонентной базы электроники гражданского и специального назначения, а также построения современных приборов на её основе. Наша основная цель – это создание и развитие научно-образовательного центра мирового уровня в области наноструктурных материалов и устройств электроники, спинтроники, фотоники, а также создание эффективной инновационной среды в области СВЧ-электронной и радиационно-стойкой компонентной базы, источников ТГц излучения, ионно-кластерных технологий материалов.

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Никитенко

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Владимир Роленович

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Теперь показываю 1 - 10 из 22

Только метаданные
On the charge mobility in disordered organics from photo-CELIV measurements
(2020) Khan, M. D.; Nikitenko, V. R.; Никитенко, Владимир Роленович
© 2020 Elsevier B.V.The analytic theory of transient current in non-equilibrium transport regime is developed for the analysis of photo-CELIV measurements. The theory allows deriving the mobility of charge carriers from photo-CELIV measurements in disordered organic thin films, providing non-equilibrium transport conditions and the finite RC value.
Только метаданные
Theoretical analysis of the drift and diffusion of charge carriers in thin layers of organic crystals
(2019) Tyutnev, A. P.; Nikerov, D. V.; Korolev, N. A.; Nikitenko, V. R.; Королев, Николай Анатольевич; Никитенко, Владимир Роленович
© 2018 Elsevier B.V. The influence of diffusion on the current shape in the time-of-flight (TOF) experiment under conditions of the quasiequilibrium transport has been considered. An analytical expression for the transient current density has been obtained for the case of the reflecting front electrode. The expression has been found to be in a better agreement with the Monte-Carlo numerical modeling than the usual expression based on the standard convection–diffusion equation. We found an estimate of the minimum layer thickness for a flat plateau appearance on TOF current transients.
Только метаданные
Analytic Modeling of the of J- V Characteristics of Quantum Dot-Based Photovoltaic Cells
(2019) Tameev, A. R.; Aleksandrov, A. E.; Saunina, A. Yu.; Nikitenko, V. R.; Chistyakov, A. A.; Zvaizgne, M. A.; Саунина, Анна Юрьевна; Никитенко, Владимир Роленович; Чистяков, Александр Александрович
An analytic model of J-V characteristics of photovoltaic devices based on quantum dot (QD) solids is developed. The model yields the upper estimation of the power conversion efficiency and predicts its extremal dependence on the diffusion length of excitons. The predictive power of our model is approved by the comparison with the experimental data for PbS QD-based solar cells.
Только метаданные
Multiple-trapping formalism for the description of charge transport in disordered organic semiconductors with correlated energy disorder
(2019) Nikitenko, V. R.; Saunina, A. Yu.; Никитенко, Владимир Роленович; Саунина, Анна Юрьевна
© 2019 Published under licence by IOP Publishing Ltd. An applicability of transport level concept, as well as multiple trapping formalism for the description of charge transport in disordered organics with correlated disorder is supported by analytic modeling of temperature and field dependence of mobility. Results of this modeling are in good agreement with well-known results of Monte-Carlo simulations. The reasons for the description of transport by the multiple trapping model and the respective parameters are discussed.
Только метаданные
Effect of microscopic Coulomb interactions on concentration dependence mobility of charge carrriers in organic materials
(2019) Nikitenko, V. R.; Saunina, A. Yu.; Никитенко, Владимир Роленович; Саунина, Анна Юрьевна
© 2019 Published under licence by IOP Publishing Ltd. The filling of deep states is considered usually to be the reason of increase of the mobility of disordered organic materials with increasing concentration. However, at moderate concentrations the effect of microscopic Coulomb interactions (MCI) could be significant, because these interactions can reduce the activation energy of a hop. It is shown, that MCI results in significant additional increase of mobility along with concentration, in addition to the effect of the filling of deep states. The results are in qualitative agreement with existing theoretical and experimental studies.
Только метаданные
Analytic Model of Nonequilibrium Charge Transport in Disordered Organic Semiconductors with Combined Energy and Off-Diagonal Disorder
(2021) Prezhdo, O. V.; Khan, M. D.; Nikitenko, V. R.; Никитенко, Владимир Роленович
© The developed generalized analytic model of charge transport in disordered matter describes self-consistently the drift and diffusion of charge carriers, includes the nonequilibrium regime, and incorporates both energy and off-diagonal (structural) disorder. The model makes it possible to accurately describe the anomalously wide transient current "tails"observed in time-of-flight experiments over wide ranges of temperature and electric field strength. Explicitly considering the off-diagonal disorder provides a more accurate description of the energy distribution of states and other parameters of the materials. The disorder contains information about the ratio of carrier diffusion coefficient to carrier mobility and characterizes the fraction of deeper localized states that inhibit mobility.
Только метаданные
PbS Quantum Dots with Inorganic Ligands: Physical Modeling of the Charge and Excitation Transport in Photovoltaic Cells
(2021) Aleksandrov, A. E.; Tameev, A. R.; Saunina, A. Y.; Zvaigzne, M. A.; Chistyakov, A. A.; Nikitenko, V. R.; Martynov, I. L.; Саунина, Анна Юрьевна; Чистяков, Александр Александрович; Никитенко, Владимир Роленович; Мартынов, Игорь Леонидович
© 2021 American Chemical Society.In photovoltaic cells based on PbS colloidal quantum dot (CQD) solids, the photoconductivity and efficiency for PbS CQDs with inorganic atomic ligands of tetrabutylammonium iodide (TBAI) are reasonably larger than those for PbS CQDs with molecular ligands of the same length. The TBAI ligands can act as electron-transporting sites and contribute to the increase in mobility. The developed simple model allows the maximum efficiency of a CQD solar cell to be determined, which can be achieved by eliminating the recombination losses of charge carriers. Both experimental data and theoretical modeling testify in favor of the hopping nature of the electron transport in CQD-solids.
Только метаданные
Role of the reorganization energy for charge transport in disordered organic semiconductors
(2021) Saxena, R.; Fishchuk, I. I.; Genoe, J.; Bassler, H.; Nikitenko, V. R.; Burdakov, Y. V.; Metel, Y. V.; Никитенко, Владимир Роленович
© 2021 American Physical Society.While it is commonly accepted that the activation energy of the thermally activated polaron hopping transport in disordered organic semiconductors can be decoupled into a disorder and a polaron contribution, their relative weight is still controversial. This feature is quantified in terms of the so-called C factor in the expression for the effective polaron mobility: μe∝exp[-Ea/kBT-C(σ/kBT)2], where Ea and σ are the polaron activation energy and the energy width of a Gaussian density of states (DOS), respectively. A key issue is whether the universal scaling relation (implying a constant C factor) regarding the polaron formation energy is really obeyed, as recently claimed in the literature [Seki and Wojcik, J. Chem. Phys. 145, 034106 (2016)10.1063/1.4958835]. In the present work, we reinvestigate this issue on the basis of the Marcus transition rate model using extensive kinetic Monte Carlo simulations as a benchmark tool. We compare the polaron-transport simulation data with results of analytical calculations by the effective medium approximation and multiple trapping and release approaches. The key result of this study is that the C factor for Marcus polaron hopping depends on first the degree of carrier localization, i.e., the coupling between the sites, further whether quasiequilibrium has indeed been reached, and finally the σ/Ea ratio. This implies that there is no universal scaling with respect to the relative contribution of polaron and disorder effect. Finally, we demonstrate that virtually the same values of the disorder parameter σ are determined from available experimental data using the C factors obtained here irrespective of whether the data are interpreted in terms of Marcus or Miller-Abrahams rates. This implies that molecular reorganization contributes only weakly to charge transport, and it justifies the use of the zero-order Miller-Abrahams rate model for evaluating the DOS width from temperature-dependent charge transport measurements regardless of whether or not polaron effects are accounted for.
Только метаданные
Anisotropic Hole Transport in a p-Quaterphenyl Molecular Crystal: Theory and Simulation
(2021) Postnikov, V. A.; Freidzon, A. Ya.; Bagaturyants, A. A.; Burdakov, Y. V.; Nikitenko, V. R.; Фрейдзон, Александра Яковлевна; Никитенко, Владимир Роленович
© 2021 American Chemical Society.A computational procedure is proposed for predicting the charge hopping rate in organic semiconductor crystals. The procedure is verified using a p-quaterphenyl molecular crystal as the test system, in which the thermally activated hole mobility is relatively low, its hole states are localized, and, hence, charge transport is of hopping character. The hole mobility in p-quaterphenyl is simulated by the Monte Carlo method with the hopping probability governed by a Marcus-like rate constant. The microscopic parameters of the Marcus model have been calculated by ab initio multireference quantum chemical method (XMCQDPT/CASSCF). Molecular conformation and crystal environment effects on the Marcus hopping parameters are studied. It is found that different arrangements of monomers typical for the crystal structure provide different hopping parameters and, hence, different hole mobilities in different directions. Monte Carlo simulations of the hole mobility predict that the hole mobility attains its maximum in the [100] direction, where hopping occurs through parallel monomers at the closest distance, which is lower than 0.01 cm2/(V·s).
Только метаданные
Increasing 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.