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Каталог книг и брошюр библиотеки ИФ СО РАН

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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim, Chang S., Aleksandrovsky A. S., Molokeev M. S., Oreshonkov A. S., Atuchin V.
Заглавие : Structural and spectroscopic effects of Li+ substitution for Na+ in LixNa1–xCaLa0.5Er0.05Yb0.45(MoO4)3 upconversion scheelite-type phosphors
Место публикации : Crystals. - 2023. - Vol. 13, Is. 2. - Ст.362. - ISSN 20734352 (eISSN), DOI 10.3390/cryst13020362
Примечания : Cited References: 63. - This study was funded by the Research Program through the Campus Research Foundation funded by Hanseo University in 2022 (2022046)
Аннотация: New triple molybdates LixNa1−xCaLa0.5(MoO4)3:Er3+0.05/Yb3+0.45 (x = 0, 0.05, 0.1, 0.2, 0.3) were manufactured successfully using the microwave-assisted sol-gel-based technique (MAS). Their room-temperature crystal structures were determined in space group I41/a by Rietveld analysis. The compounds were found to have a scheelite-type structure. In Li-substituted samples, the sites of big cations were occupied by a mixture of (Li, Na, La, Er, Yb) ions, which provided a linear cell volume decrease with the Li content increase. The increased upconversion (UC) efficiency and Raman spectroscopic properties of the phosphors were discussed in detail. The mechanism of optimization of upconversion luminescence upon Li content variation was shown to be due to the control of excitation/energy transfer channel, while the control of luminescence channels played a minor role. The UC luminescence maximized at lithium content x = 0.05. The mechanism of UC optimization was shown to be due to the control of excitation/energy transfer channel, while the control of luminescence channels played a minor role. Over the whole spectral range, the Raman spectra of LixNa1−xCaLa0.5(MoO4)3 doped with Er3+ and Yb3+ ions were totally superimposed with the luminescence signal of Er3+ ions, and increasing the Li+ content resulted in the difference of Er3+ multiple intensity. The density functional theory calculations with the account for the structural disorder in the system of Li, Na, Ca, La, Er and Yb ions revealed the bandgap variation from 3.99 to 4.137 eV due to the changing of Li content. It was found that the direct electronic transition energy was close to the indirect one for all compounds. The determined chromaticity points (ICP) of the LiNaCaLa(MoO4)3:Er3+,Yb3+ phosphors were in good relation to the equal-energy point in the standard CIE (Commission Internationale de L’Eclairage) coordinates.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim, Chang-Sung, Aleksandrovsky A. S., Molokeev M. S., Oreshonkov A. S., Atuchin V. V.
Заглавие : Structural and spectroscopic effects of Li+ substitution for Na+ in LixNa1-xCaGd0.5Ho0.05Yb0.45(MoO4)3 scheelite-type upconversion phosphors
Место публикации : Molecules. - 2021. - Vol. 26, Is. 23. - Ст.7357. - ISSN 1420-3049 (eISSN), DOI 10.3390/molecules26237357
Примечания : Cited References: 77. - This study was supported by the Research Program through the Campus Research Foundation funded by Hanseo University in 2021 (211Yunghap06)
Аннотация: A set of new triple molybdates, LixNa1-xCaGd0.5(MoO4)3:Ho3+0.05/Yb3+0.45, was successfully manufactured by the microwave-accompanied sol–gel-based process (MAS). Yellow molybdate phosphors LixNa1-xCaGd0.5(MoO4)3:Ho3+0.05/Yb3+0.45 with variation of the LixNa1-x (x = 0, 0.05, 0.1, 0.2, 0.3) ratio under constant doping amounts of Ho3+ = 0.05 and Yb3+ = 0.45 were obtained, and the effect of Li+ on their spectroscopic features was investigated. The crystal structures of LixNa1-xCaGd0.5(MoO4)3:Ho3+0.05/Yb3+0.45 (x = 0, 0.05, 0.1, 0.2, 0.3) at room temperature were determined in space group I41/a by Rietveld analysis. Pure NaCaGd0.5Ho0.05Yb0.45(MoO4)3 has a scheelite-type structure with cell parameters a = 5.2077 (2) and c = 11.3657 (5) Å, V = 308.24 (3) Å3, Z = 4. In Li-doped samples, big cation sites are occupied by a mixture of (Li,Na,Gd,Ho,Yb) ions, and this provides a linear cell volume decrease with increasing Li doping level. The evaluated upconversion (UC) behavior and Raman spectroscopic results of the phosphors are discussed in detail. Under excitation at 980 nm, the phosphors provide yellow color emission based on the 5S2/5F4 → 5I8 green emission and the 5F5 → 5I8 red emission. The incorporated Li+ ions gave rise to local symmetry distortion (LSD) around the cations in the substituted crystalline structure by the Ho3+ and Yb3+ ions, and they further affected the UC transition probabilities in triple molybdates LixNa1-xCaGd0.5(MoO4)3:Ho3+0.05/Yb3+0.45. The complex UC intensity dependence on the Li content is explained by the specificity of unit cell distortion in a disordered large ion system within the scheelite crystal structure. The Raman spectra of LixNa1-xCaGd0.5(MoO4)3 doped with Ho3+ and Yb3+ ions were totally superimposed with the luminescence signal of Ho3+ ions in the range of Mo–O stretching vibrations, and increasing the Li+ content resulted in a change in the Ho3+ multiplet intensity. The individual chromaticity points (ICP) for the LiNaCaGd(MoO4)3:Ho3+,Yb3+ phosphors correspond to the equal-energy point in the standard CIE (Commission Internationale de L’Eclairage) coordinates.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Chang Sung Lim, Won-Chun Oh, Aleksandrovsky A. S., Atuchin V. V., Molokeev M. S., Oreshonkov A. S.
Заглавие : Scheelite type microcrystalline AgGd(MoO4)2:Yb3+/Ho3+ upconversion yellow phosphors by MES based synthesis and their spectroscopic properties for biomedical applications
Коллективы : International Conference on Multifunctional Materials and Application
Место публикации : The 15th International conference on multifunctional materials and application. - 2021. - Ст.PO8. - P.75-76
Примечания : Cited References: 4
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Chang Sung Lim, Won-Chun Oh, Aleksandrovsky A. S., Atuchin V. V., Molokeev M. S., Oreshonkov A. S.
Заглавие : Microwave sol-gel derived Ho3+/Yb3+ co-doped NaCaGd(MoO4)3 yellow phosphors and their upconversion photoluminescence properties for optoelectronic devices
Коллективы : International Conference on Multifunctional Materials and Application
Место публикации : The 15th International conference on multifunctional materials and application. - 2021. - Ст.PO7. - P.73-74
Примечания : Cited References: 4
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim, Chang Sung, Aleksandrovsky A. S., Atuchin V. V., Molokeev M. S., Oreshonkov A. S.
Заглавие : Microwave sol-gel synthesis, microstructural and spectroscopic properties of scheelite-type ternary molybdate upconversion phosphor NaPbLa(MoO4)3:Er3+/Yb3+
Место публикации : J. Alloys Compd. - 2020. - Vol. 826. - Ст.152095. - ISSN 0925-8388 (ISSN), DOI 10.1016/j.jallcom.2019.152095. - ISSN 1873-4669 (eISSN)
Примечания : Cited References: 53. - This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2018R1D1A1A09082321). This study was supported by the Russian Science Foundation (19-42-02003, in part of conceptualization). Also, this study was supported by RFBR (18-32-20011, 18-03-00750).
Аннотация: New ternary molybdate NaPbLa(1-x-y)(MoO4)3:xEr3+,yYb3+ (x = y = 0, x = 0.05 and y = 0.35, 0.4, 0.45 and 0.5) phosphors were successfully fabricated by the MSG (microwave sol-gel) method, and the microstructural and spectroscopic properties were characterized. The crystal structure of NaPbLa(MoO4)3 (NPLM) was defined by Rietveld analysis in space group I41/a with unit cell parameters a = 5.3735(2) and c = 11.8668(4) Å, V = 342.65(3) Å3, Z = 4 (RB = 6.64%). The unit cell volume of NaPbLa(MoO4)3 (NPLM) was intermediate between those of NaLa(MoO4)2 and PbMoO4. Under the 980 nm excitation, upconverted yellowish-green emissions at transitions from 2H11/2 and 4S3/2 were observed. No concentration quenching in the subsystem of donor ions at the content up to 50 at.% and no cross-relaxation losses in the subsystem of acceptor ions at the concentrations as high as 5 at. % were verified. The individual chromaticity points for the NaPbLa(MoO4)3:Er3+,Yb3+ phosphors, corresponding to the equal-energy point in the standard CIE diagram, revealed yellowish-green emissions.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim C. S., Aleksandrovsky A. S., Atuchin V., Molokeev M. S., Oreshonkov A. S.
Заглавие : Microwave-employed sol–gel synthesis of scheelite-type microcrystalline AgGd(MoO4)2:Yb3+/Ho3+ upconversion yellow phosphors and their spectroscopic properties
Место публикации : Crystals. - 2020. - Vol. 10, Is. 11. - Ст.1000. - P.1-14. - ISSN 20734352 (ISSN), DOI 10.3390/cryst10111000
Примечания : Cited References: 58. - This study was supported by the Research Program through the Campus Research Foundation funded by Hanseo University in 2020 (201Yunghap09)
Аннотация: AgGd(MoO4)2:Ho3+/Yb3+ double molybdates with five concentrations of Ho3+ and Yb3+ were synthesized by the microwave employed sol–gel based process (MES), and the crystal structure variation, concentration effects, and spectroscopic characteristics were investigated. The crystal structures of AgGd1−x−yHoxYby(MoO4)2 (x = 0, 0.05; y = 0, 0.35, 0.4, 0.45, 0.5)at room temperature were determined in space group I41/a by Rietveld analysis. Pure AgGd(MoO4)2 has a scheelite-type structure with mixed occupations of (Ag,Gd) sites and cell parameters a = 5.24782 (11) and c = 11.5107 (3) Å, V = 317.002 (17) Å3, Z = 4. In doped samples, the sites are occupied by a mixture of (Ag,Gd,Ho,Yb) ions, which provides a linear cell volume decrease with the doping level increase. Under the excitation at 980 nm, AGM:0.05Ho,yYb phosphors exhibited a yellowish green emission composed of red and green emission bands according to the strong transitions 5F5 → 5I8 and 5S2/5F4 → 5I8 of Ho3+ ions. The evaluated photoluminescence and Raman spectroscopic results were discussed in detail. The upconversion intensity behavior dependent on the Yb/Ho ratio is explained in terms of the optimal number of Yb3+ ions at the characteristic energy transfer distance around the Ho3+ ion.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Guan M., Molokeev M. S., Zhou J.
Заглавие : Atomic deciphering of cation exchange mechanism in upconversion nanoparticles
Место публикации : J. Lumin. - 2020. - Vol. 224. - Ст.117289. - ISSN 00222313 (ISSN), DOI 10.1016/j.jlumin.2020.117289
Примечания : Cited References: 36. - The authors acknowledge the Science and Technology Innovation Committee of Shenzhen (Grant No. KQTD20170810110913065), Australian Research Council (ARC) Discovery Early Career Researcher Award Scheme (J. Z., DE 180100669), and the China Scholarship Council (Ming Guan, No. 201506400025)
Аннотация: Transition metal ion doping in upconversion nanoparticles (UCNPs) provides an effective way to enhance the luminescence for their wide array of applications. However, the doping sites of transition metal ions have not been comprehensively explored, and commonly assumed that transition metal ions replace the trivalent lanthanides within the lattice. Here we report that cation exchange of transition metal (Mn2+) in β-NaYF4:Yb3+/Er3+ UCNPs occurs through alkaline metal (Na+) replacement, via 2Na+ ↔ Mn2+ + Vacancy reaction. This process distorts the LnF9 polyhedrons and tailors the surrounding environment around the trivalent lanthanides, thereby improving the upconversion intensity from active lanthanides. Further confirmed by core-shell design and spectroscopic study, we prove that the transition–alkaline metal exchange enables both the emission enhancement and transition probability variation of activators.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim, Chang Sung, Atuchin V. V., Aleksandrovsky A. S., Denisenko, Yuriy G., Molokeev M. S., Oreshonkov A. S.
Заглавие : Fabrication of Microcrystalline NaPbLa(WO4)3:Yb3+/Ho3+ Phosphors and Their Upconversion Photoluminescent Characteristics
Место публикации : Kor. J. Mater. Res. - 2019. - Vol. 29, Is. 12. - P.741-746. - ISSN 1225-0562, DOI 10.3740/MRSK.2019.29.12.741. - ISSN 2287-7258 (eISSN)
Примечания : Cited References: 28. - This study was supported by the Research Program through the Campus Research Foundation funded by Hanseo University in 2019 (191Yunghap09) and the Russian Science Foundation (19-42-02003). The authors are grateful for the support from RFBR, according to the research project 18-32-20011.
Аннотация: New triple tungstate phosphors NaPbLa(WO4)3:Yb3+/Ho3+ (x = Yb3+/Ho3+ = 7, 8, 9, 10) are successfully fabricated by microwave assisted sol-gel synthesis and their structural and frequency upconversion (UC) characteristics are investigated. The compounds crystallized in the tetragonal space group I41/a and the NaPbLa(WO4)3 host have unit cell parameters a = 5.3927(1) and c = 11.7961(3) Å, V = 343.05(2) Å3, Z = 4. Under excitation at 980 nm, the phosphors have yellowish green emissions, which are derived from the intense 5S2/ 5F4 → 5I8 transitions of Ho3+ ions in the green spectral range and strong 5F5 → 5I8 transitions in the red spectral range. The optimal Yb3+:Ho3+ ratio is revealed to be x = 9, which is attributed to the quenching effect of Ho3+ ions, as indicated by the composition dependence. The UC characteristics are evaluated in detail under consideration of the pump power dependence and Commission Internationale de L'Eclairage chromaticity. The spectroscopic features of Raman spectra are discussed in terms of the superposition of Ho3+ luminescence and vibrational lines. The possibility of controlling the spectral distribution of UC luminescence by the chemical content of tungstate hosts is demonstrated.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Razumkova I. A., Denisenko Yu. G., Boyko A. N., Ikonnikov D. A., Aleksandrovsky A. S., Azarapin N. O., Andreev O. V.
Заглавие : Synthesis and Upconversion Luminescence in LaF3:Yb3+, Ho3+, GdF3: Yb3+, Tm3+ and YF3:Yb3+, Er3+ obtained from Sulfide Precursors
Место публикации : Z. Anorg. Allg. Chem. - 2019. - Vol. 645, Is. 24. - P.1393-1401. - ISSN 0044-2313, DOI 10.1002/zaac.201900204; J. Inorg. General Chem. - ISSN 1521-3749 (eISSN)
Примечания : Cited References: 57. - The authors would like to thank the staff of the Engineering Center of the Tyumen State University (special Alexej V. Matigorov) for their help in carrying out physical and chemical tests.
Аннотация: Rare earth fluorides are mainly obtained from aqueous solutions of oxygen‐containing precursors. Probably, this method is simple and efficient, however, oxygen may partially be retained in the fluoride structure. We offer an alternative method: obtaining fluorides and solid solutions based on them from an oxygen‐free precursor. As starting materials, we choose sulfides of rare‐earth elements and solid solutions based on them. The fluorination is carried out by exposure to hydrofluoric acid of various concentrations. The transmission electron microscopy images revealed the different morphologies of the products, which depend on the concentration of the fluorinating component (HF) and the host element. The solid solution particle size varied from 30–35 nm in the case of GdF3:Yb3+, Tm3+ (4 % HF) to larger structures with dimensions exceeding 200 nm, such as that for LaF3:Yb3+, Ho3+ (40 % HF). The thermal characteristics, such as the temperatures of the transitions and melting and enthalpies, were determined for the solid solutions and simple fluorides. Applicability of the materials obtained as biological luminescent markers was tested on the example of upconversion luminescence, and good upconversion properties were detected.
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