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Каражанов, Смагул Жангабергенович

Организационные подразделения

Организационная единица

Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.

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Каражанов

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Смагул Жангабергенович

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Только метаданные
Visible light-assisted instability of kesterite Cu2ZnSnS4: What are the implications?
(2020) Kois, J.; Polivtseva, S.; Samieipour, A.; Mamedov, D.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
© 2019The development of efficient photovoltaic devices utilizing durable and cost-effective materials such as CZTS and similar ones represents a big challenge. Here, the comparison of thermodynamic calculations and electrochemical experiments reveals detrimental degradation of CZTS regardless of pH values and potentials applied. Cathodic polarization yields to the full decomposition of CZTS, while anodic polarization stabilizes partly CZTS by passivation of its surface with less-active phases. The presence of water, in general, provokes the decomposition of CZTS to various undesired phases which most likely affect the device parameters. The possible mechanism for the degradation of CZTS is proposed considering its electronic structure. Certain similarities on unfavorable processes occurring with analogous materials are expected.
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Comparative analysis of photothermal boiling of water enhanced by nano- and micro-particles of carbon black
(2021) Ulset, E. T.; Kosinski, P.; He, Y.; Struchalin, P. G.; Karazhanov, S. Z.; Balakin, B. V.; Стручалин, Павел Геннадьевич; Каражанов, Смагул Жангабергенович
© 2020 Elsevier B.V.The paper describes the effect of sodium dodecyl sulfate (SDS) on the steam generation during photothermal boiling of carbon nanofluids. The considered process finds promising applications for e.g. solar desalination where SDS may boost steam generation. Our study was carried out in a lab system boiling aqueous suspensions of carbon by means of artificial thermal radiation. The experiments demonstrate that the newly-produced nanofluids turn into suspension when no SDS is present in the fluid. The agglomeration of nanoparticles reduces the stability of the system yet degrades the steam generation by no more than 8.2%. The optimum particle concentration was about 2% wt. independently of whether SDS was present in samples. The steam was superheated by up to 12 K when using the surfactant which was 5–7 K higher than without SDS. The experimental data was supported by a theoretical analysis.
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Doping-induced modulation of electronic, optical and wetting properties of CeO2
(2022) Mamedov, D.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
Recently, CeO2 as well as other Rare-Earth Oxides (REOs) have become known as water repelling materials which enables their usage in glass industry. In this study, we investigate electronic, optical and wetting properties of pure and doped CeO2 by first-principles calculations. It is established that introduction of tetravalent doping atoms (Zr, Ti, Sn and Si) significantly modifies the optical response of CeO2 in the visible range by shifting the absorption edge which also effects on the refractive index of the material. For these systems, the water contact angle has been computed through adsorption energy of water layers. We report the intrinsic hydrophilicity of the low-index surfaces of CeO2, which is enhanced by introduction of the impurity atom. Influence of the dopants on the oxygen vacancy formation energy Ef(VO) is considered and discussed with respect to its possible effect on the hydrophobic behavior of CeO2. It is found out that all the considered doping atoms reduce Ef(VO), resulting in enhanced adsorption of the air hydrocarbons at the surface, which leads to an increased water contact angle. Based on the obtained results, an assessment on the applicability of doped CeO2 in glass industry is made. It is concluded that Zr-doped CeO2 possesses the most prominent properties among considered systems for the application as transparent layer. © 2022 The Authors
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Environmental dependence of the photochromic effect of oxygen-containing rare-earth metal hydrides
(2021) Stolz, L.; Moro, M. V.; Adalsteinsson, S. M.; Chioar, I. A.; Moldarev, D.; Karazhanov, S. Z.; Wolff, M.; Каражанов, Смагул Жангабергенович
© 2021 Author(s).We study the dependence of the photochromic effect on environment and triggering light. We demonstrate that the first darkening/bleaching cycle of freshly grown films is accompanied by a release of weakly bound hydrogen, most likely present at the grain boundaries. For consecutive photochromic cycles, we do not find further exchange of material with the environment. Moreover, we report bleaching kinetics dependent on the gas environment after darkening with light of energies below the optical bandgap of the film. For darkening with photon energies above the bandgap of the film, we report a linear relation between the degree of darkening and bleaching relaxation time irrespective of gas environment.
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Influence of Si-nanoparticles on PEDOT:PSS properties for hybrid solar cells
(2019) Mamedov, D.; You, C. C.; Karazhanov, S. Z.; Marstein, E. S.; Каражанов, Смагул Жангабергенович
Hole-conducting poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a material receiving increasing interest for use in photovoltaic devices. In this work, we present the results of study of the degradation of the optical and electrical properties of pure PEDOT:PSS and PEDOT:PSS doped with Si-nanoparticles. The PEDOT:PSS has been deposited on top of Si wafers by spin coating. We found that incorporation of Si nanoparticles into PEDOT:PSS enhances the surface passivation of the surface of the Si wafer by increasing the carrier lifetime measured by the photoluminesence quasi-steady state photoconductance (PL QSS-PC) method from about 320 ms to 420 ms at a minority carrier injection level of 2*10(15) cm(-3). Analysis showed that incorporation of the Si nanoparticles does not change the kinetics of degradation of lifetime considerably. (c) 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the E-MRS Fall Meeting, 2019. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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In-situ composition analysis of photochromic yttrium oxy-hydride thin films under light illumination
(2019) Moro, M. V.; You, C. C.; Baba, E. M.; Primetzhofer, D.; Moldarev, D.; Karazhanov, S. Z.; Wolff, M.; Каражанов, Смагул Жангабергенович
© 2019 Elsevier B.V.In this work, we investigate the chemical composition of a reactively sputtered photochromic YHxOy thin film by non-destructive ion beam-based techniques, i.e., Rutherford Backscattering Spectrometry, Particle-Induced X-Ray Emission, Time-of-Flight/Energy coincidence Elastic Recoil Detection Analysis and Elastic Backscattering Spectrometry. To enhance the accuracy of the analysis, the set of spectra was evaluated in an iterative self-consistent approach. This procedure resulted in high-resolution depth profiles of the chemical composition and revealed a thin oxygen-rich-layer on the surface, which apparently does not act as a self-passivation layer. In the film, the concentration of Y remains practically constant, whereas O replaces H during the oxidation process. In-situ light illumination was performed during the compositional analysis in a high vacuum setup. The results from these measurements demonstrate that, for these samples, the induced reversible photochromism is not linked to any detectable change in the bulk composition of the film and can thus take place even in a vacuum environment.
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Electrical and optical properties of composite PEDOT:PSS-based thin films with NiO nanoparticles
(2019) Moldarev, D.; Taeno, M.; Maestre, D.; Cremades, A.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
Due to the combination of low cost materials deposition and device fabrication methods as well as competitive efficiency compared to the other Si solar cell architectures, the hybrid organic-silicon solar cells have attracted attention of the scientific community. It has recently been demonstrated that spin-coated poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (hereafter PEDOT:PSS) on a silicon wafer is a promising material due to its good optical and electrical properties. However, degradation caused by atmospheric exposure and relatively poor passivation properties limits implementation of PEDOT:PSS- silicon devices. Functionalization of PEDOT:PSS by inorganic nanoparticles might provide a possible solution as was shown for TiO2 and SnO2 nanoparticles. In this contribution, we present our results on spincoated PEDOT:PSS thin-films with NiO nanoparticles. We show that PEDOT:PSS mixed with Triton X-100 and dimethyl sulfoxide (DMSO) or ethylene glycol (EG) form a homogenous film and passivates the Si surface with charge carrier lifetimes of 300-400 ms with good reproducibility. Time-resolved measurements revealed continuous degradation of the passivation properties in air, however saturation of the degradation at approximately 150 ms was observed in N-2 atmosphere. The influence of the NiO nanoparticles on the optical properties of PEDOT:PSS is negligible, whereas the surface passivation properties are worsened due probably to the formation of large size agglomerates exceeding thickness of PEDOT:PSS film. (c) 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the E-MRS Fall Meeting, 2019.
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Photochromic properties of yttrium oxyhydride thin films: Surface versus bulk effect
(2020) Baba, E. M.; Moro, M. V.; You, C. C.; Primetzhofer, D.; Moldarev, D.; Wolff, M.; Karazhanov, S. Z.; Каражанов, Смагул Жангабергенович
© 2020Photochromic yttrium oxyhydride (YHO) films of different thicknesses but similar chemical composition were grown by reactive magnetron sputtering. Photochromic response of the films defined as the relative change in transmittance upon illumination increases almost linearly with thickness for films below 600 nm and saturates (≈ 50%) for thicker ones. These results suggest that the photochromic effect on YHO films has a bulk nature and might be limited by material transport on the microscale.