Библиотека института физики им. Л.В. Киренского СО РАН

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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) : Balaev D. A., Krasikov A. A., Knyazev Yu. V., Yaroslavtsev R. N., Velikanov D. A., Mikhlin Yu. L., Volochaev M. N., Bayukov O. A., Ladygina V. P., Stolyar S. V., Iskhakov R. S.
Заглавие : Magnetic collective state formation upon tuning the interparticle interactions in ensembles of ultrafine ferrihydrite nanoparticles
Колич.характеристики :13 с
Место публикации : Nano-Struct. Nano-Objects. - 2024. - Vol. 37. - Ст.101089. - ISSN 2352507X (ISSN), DOI 10.1016/j.nanoso.2023.101089. - ISSN 23525088 (eISSN)
Примечания : Cited References: 93. - The authors thank M.N. Volochaev for the TEM investigations
Аннотация: The results of a study of the dynamic (alternating current magnetic susceptibility) and static magnetic properties, as well as 57Fe Mössbauer spectrometry and ferromagnetic resonance of two-line ferrihydrite nanoparticle systems with varying intensities of magnetic interparticle interactions are reported. The strength of the magnetic interparticle interactions has been tuned by coating (with various degrees of coating) the ferrihydrite particles (2–4 nm in size and an average size ∼2.7 nm) of the initial synthetic sample by arabinogalactan. Also, a biogenic ferrihydrite sample (an average particle size of 2-nm) with a natural organic coating was studied and it has the weakest magnetic interparticle interactions among of all the samples. Relaxation times of the particle’s magnetic moment were determined by the data of static and dynamic magnetic susceptibilities and from analysis of 57Fe Mössbauer spectrometry. Based on the temperature dependences of the relaxation times, it has been concluded that the predominantly collective processes of freezing of the particle magnetic moments occur under the action of the magnetic interparticle interactions. It is shown that an important role in these processes is played by a magnetic subsystem of the surface spins of the particles. The effect of the interplay between the surface spin and magnetic moment subsystems on the static magnetic properties (low-temperature magnetic hysteresis loops) and the parameters of the microwave absorption line under the magnetic resonance conditions is discussed.
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Вид документа : Статья из журнала
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Автор(ы) : Flerov I. N., Gorev M. V., Bogdanov E. V., Laptash N. M.
Заглавие : Chemical pressure as an effective tool for tuning the structural disordering and barocaloric efficiency of complex fluorides (NH4)3MF7 (M: Sn, Ti, Ge, Si)
Колич.характеристики :18 с
Место публикации : J. Phys. D: Appl. Phys. - 2024. - Vol. 57, Is. 17. - Ст.175301. - ISSN 00223727 (ISSN), DOI 10.1088/1361-6463/ad211b. - ISSN 13616463 (eISSN)
Примечания : Cited References: 39. - The study was supported by a Grant from the Russian Science Foundation No. 23-22-00115, https://rscf.ru/project/23-22-00115/
Аннотация: Double fluoride salts (NH4)3M4+F7 (M4+: Sn, Ti, Ge, Si) demonstrate a high efficiency of using chemical pressure as a tool for control and tuning structural ordering/disordering, sensitivity to hydrostatic pressure, successions of the phase transitions, etc and, as a result, for purposeful variation within a wide range of parameters of barocaloric effect (BCE). The conventional and inverse BCEs near the triple points were found on the T − p phase diagrams, combination of which can be used to construct original cooling cycle in narrow temperature and pressure ranges. Reconstructive transformation between two cubic phases, Pm3-m ↔ Pa3-, realized in (NH4)3SnF7 at atmospheric pressure and in (NH4)3TiF7 at p ˃ 0.4 GPa are characterized by rather low thermal hysteresis, δT0 = 1 K, and a great entropy change, ΔSBCE = 110–152 J (kg · K)−1, depending on the size of the central atom. At above 300–350 K, a contribution to BCE associated with the regular thermal expansion of the crystal lattice becomes comparable to entropy and temperature changes under pressure in the region of the phase transitions. An analysis of the absolute, relative and integral barocaloric characteristics of (NH4)3M4+F7 compounds showed their high competitiveness with respect to other barocaloric materials considered as promising solid-state refrigerants.
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Вид документа : Статья из журнала
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Автор(ы) : Rudakova N. V., Bikbaev R. G., Tyryshkina L. E., Vetrov S. Ya., Timofeev I. V.
Заглавие : Tuning Q-factor and perfect absorption using coupled Tamm states on polarization-preserving metasurface
Колич.характеристики :12 с
Место публикации : Photonics. - 2023. - Vol. 10, Is. 12. - Ст.1391. - ISSN 23046732 (eISSN), DOI 10.3390/photonics10121391
Примечания : Cited References: 58
Аннотация: The circular polarization of light flips its handedness after a conventional metallic mirror reflection. Therefore, a polarization-preserving metasurface is a crucially important element in a series of chiral photonic structures. They include tunable cholesteric LCs and anisotropic photonic crystals. Chiral structures are rich in interfacial localized modes including Tamm states. In this report, coupled modes formed as a result of the interaction between two chiral optical Tamm states or a chiral optical Tamm state and a chiral Tamm plasmon polariton are analytically and numerically investigated. It is shown that the effective control of coupled modes can be carried out by changing the pitch of the cholesteric and the angle between the optical axis of the cholesteric and the polarization-preserving anisotropic mirror. The influence of the metasurface period on the spectral characteristics of coupled modes is investigated. The possibility of realizing a bound state in the continuum of the Friedrich–Wintgen type, resulting from the destructive interference of coupled modes, which leads to the collapse of the resonance line corresponding to the chiral optical Tamm state, has been demonstrated.
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Вид документа : Статья из журнала
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Автор(ы) : Zhou, Cheng, Peng, L.u., Kong, Zihui, Wu, Meihan, Molokeev M. S., Zhou, Zhi, Wang, Jing, Xia, Mao
Заглавие : A high thermal stability Cr3+-doped gallate far red phosphor for plant lighting: structure, luminescence enhancement and application prospect
Место публикации : J. Mater. Chem. C. - 2022. - Vol. 10, Is. 15. - P.5829-5839. - ISSN 2050-7526, DOI 10.1039/d2tc00614f. - ISSN 2050-7534(eISSN)
Примечания : Cited References: 39. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (Grant no. 51974123), the Distinguished Youth Foundation of Hunan Province (Grant no. 2020JJ2018), Key R & D projects in Hunan Province (2020WK2016 & 2020SK2032), the Hunan High Level Talent Gathering Project (2019RS1077 & 2020RC5007), the Natural Sciences Foundation of Hunan Agricultural University (19QN11), the Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), the Changsha Science and technology plan (KH2005114), the Scientific Research Fund of Hunan Provincial Education Department (19C0903) and the Innovation Training Program for College Students of Hunan Province (No. S202010537012)
Предметные рубрики: EMITTING PHOSPHOR
TUNING PHOTOLUMINESCENCE
LEDS
Аннотация: Cationic substitution is a common material modification strategy. Generally, it follows the principles of radius matching, valency equilibrium and stoichiometric substitution. However, radius-mismatched, nonstoichiometric-ratio ion substitution can achieve unexpected experimental results. Such unexpected results are very important for expanding the research of materials, but the modification mechanism is still unclear. In this work, the optical performance of ZnGa2O4:0.02Cr3+ (ZGO:0.02Cr3+) is effectively regulated by chemical unit cosubstitution (Ge4+–Li+/Na+ for Ga3+–Zn2+) and excess cation substitution synergetic strategies, and the thermal stability is retained at 97.7% at room temperature and 150 °C. Ge4+–Li+ and Ge4+–Na+ replace the lattice position of Ga3+–Zn2+ to enhance the photoluminescence (PL) intensity and quantum efficiency (QE) of ZGO:0.02Cr3+. The optimal doping contents of Ge4+–Li+ and Ge4+–Na+ are all 0.3 mol (PL intensity is 130.3% and 153.4% and QE = 77.4% and 85.1%). With further addition of Li+ ions, the emission intensity and QE continued to increase to 176.4% and 83.8%, respectively. The synergistic effect of the mechanism on optical properties is explained via Rietveld refinement, optical band gap energy and thermoluminescence. Finally, LED devices were fabricated by using the ZGO:0.02Cr3+,0.03Ge4+,0.11Li+ phosphor to investigate the effect on plant growth. The growth period was reduced and the fruit quality was improved in dwarf potted tomato, which shows the application prospect in plant growth of the ZGO:0.02Cr3+ phosphor.
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Вид документа : Статья из журнала
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Автор(ы) : Yan W., Wei Y., Molokeev M. S., Wang S., Li G.
Заглавие : Green-emitting Bi3+-doped La2SrSc2O7 phosphor for pc-WLED lighting: Luminescent properties and energy transfer strategy
Место публикации : J. Alloys Compd. - 2022. - Vol. 908. - Ст.164621. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2022.164621
Примечания : Cited References: 63. - This work was supported by the National Natural Science Foundation of China (Grant Nos. 52072349)
Аннотация: The crystal structure, photoluminescence properties, thermal stability and corresponding mechanisms of the novel Bi3+, Eu3+-doped La2SrSc2O7 (LSS) phosphors have been measured and analyzed in details. The emission spectrum of LSS: 1.0%Bi3+ phosphor shows a novel green emission centered at 530 nm under 340 nm excitation, which is attributed to the 3P1→1S0 transition of Bi3+ ions. By designing Bi3+→Eu3+energy transfer strategy, luminescence colors of LSS: 1.0%Bi3+, yEu3+ (y = 0–5.0%) phosphors can be tuned from green to orange with increasing Eu3+ concentration, which achieve multiple emission colors in LSS host. The photoluminescence decay curves, average decay lifetimes, energy transfer efficiency and time-resolved emission spectra of LSS: 1.0%Bi3+, yEu3+ (y = 0–5.0%) phosphors prove the existence of energy transfer from Bi3+ to Eu3+. The prototype pc-WLED device with green-emitting LSS: 1.0%Bi3+ possesses high color rendering index (CRI = 96.0) and low correlated color temperature (CCT = 4306 K). These results provide clear evidences that LSS: Bi3+and LSS: 1.0%Bi3+, Eu3+ phosphors would be novel promising green-to-orange tunable phosphor candidates for pc-WLED applications.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gao P. -X., Dong P., Zhou Z. -Y., Zhang X. -J., Li Y. -N., Yang J. -K., Li Q., Chen K., Molokeev M. S., Zhou Z., Xia M.
Заглавие : Novel far-red phosphors (La, Gd, Y)2MgTiO6:Cr3+ with tunable luminescence spectra for grow light
Разночтения заглавия :
Место публикации : Faguang Xuebao/Chin. J. Lumines. - 2022. - Vol. 43, Is. 1. - P.58-68. - ISSN 10007032 (ISSN), DOI 10.37188/CJL.20210327
Примечания : Cited References: 27. - Supported by National Natural Science Foundation of China(51974123); The Distinguished Youth Foundation of Hunan Province(2020JJ2018); Key R & D Projects in Hunan Province(2020WK2016&2020SK2032&2022NK2044), Hunan High Level Talent Gathering Project(2019RS1077&2020RC5007); Natural Science Foundation of Hunan Province(2021JJ40261); The Scientific Research Fund of Hunan Provincial Education Department(19C0903); The Natural Sciences Foundation of Hunan Agricultural University(19QN11); Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation(19KFXM12); Changsha Science and Technology Plan(KH2005114)
Аннотация: Cr3+-activated double perovskite structure phosphor has drawn wide attention due to its far-red and near-infrared emission. In this work, we synthesized a series of (La,Gd,Y)2MgTiO6∶Cr3+ phosphors which can be excited by ultraviolet light of about 345 nm, and the emission bands are in the range of 700-900 nm. The spectra were tuned by ions substitution strategy. The main emission peaks were blue shifted from 766 nm to 737 nm and 757 nm by substituting the La site with Gd and Y, respectively. Meanwhile, the thermal stability at 150 ℃ increased from 41.7% to 69.1% and 67%, respectively. The crystal structure, microstructure, decay time, thermal stability and band gap were investigated systematically. The substitution of Gd/Y ions causes the lattice contraction, which results in the change of the nephelauxetic effect, and eventually leads to the blue shift of the spectra. The emission spectra of these phosphors have good matching with the 730 nm absorption peak of phytochrome FR(PFR), indicating their application prospect in plant growth lighting. Cationic substitution strategy can regulate the luminescence properties of Cr3+, which provides ideas for the development of phosphors for plant growth lamps in the future.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gao P., Li Q., Li S., Gai S., Li Y., Ma Y., Zhang Z., Molokeev M. S., Zhou Z., Xia M.
Заглавие : Multiple strategies to approach high-efficiency luminescence controllable in blue/cyan/green-emitting Bi3+-activated phosphors
Место публикации : J. Phys. Chem. C. - 2022. - Vol. 126, Is. 21. - P.9195-9206. - ISSN 19327447 (ISSN), DOI 10.1021/acs.jpcc.2c02560
Примечания : Cited References: 53. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (grant no. 51974123), the Distinguished Youth Foundation of Hunan Province (grant no.2020JJ2018), the Key R&D projects in Hunan Province (2020WK2016, 2020SK2032, 2021SK2047, and 2022NK2044), the Natural Science Foundation of Hunan Province, China (grant no. 2021JJ40261), the Hunan High Level Talent Gathering Project (2019RS1077 and 2020RC5007), the Scientific Research Fund of Hunan Provincial Education Department (19C0903), the Natural Sciences Foundation of Hunan Agricultural University, China (grant no. 19QN11), the Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), the Changsha Science and Technology Plan (KH2005114, KH2201428), and the College Students’ Innovative Training (S202110537012)
Аннотация: Cyan gap is a major block in achieving high-quality white light-emitting diodes (WLEDs). Hence, a novel cyan-emitting phosphor Sr2GdGaO5/0.02Bi3+ with optical tuning performance is synthesized based on the local crystal field regulation strategy surrounding the luminescence center. With the substitution of Al3+ for Ga3+, the photoluminescence (PL) spectra of Sr2GdGa1–xAlxO5/0.02Bi3+ (0 ≤ x ≤ 1) phosphors adjust from cyan (466 nm) to blue (450 nm). Moreover, such a Ba2+ doping adjusts the PL spectra of Sr2–xBaxGdGaO5/0.02Bi3+ (0 ≤ x ≤ 0.5) phosphors from cyan (466 nm) to green (482 nm). These phenomena are contributed to the crystal field splitting and nephelauxetic effect. The energy transfer from Bi3+ to Eu3+ is realized by co-doping Bi3+ and Eu3+ ions in the A2GdBO5/Bi3+ (A = Sr, Ba; B = Ga, Al) host materials, and two single-phase white phosphors Sr2GdGaO5/0.02Bi3+, 0.05Eu3+ and Sr1.5Ba0.5GdGaO5/0.02Bi3+, 0.05Eu3+ are obtained. Finally, a WLED with high color rendering index (Ra = 93.6) is prepared by using red/green/blue (RGB) phosphors and Sr2GdGaO5/0.02Bi3+ phosphor, which is higher than that of the WLED prepared by RGB phosphors (Ra = 86.7), indicating that Sr2GdGaO5/0.02Bi3+ phosphor can close the cyan gap. These results provide multiple strategies in achieving luminescence controllable and WLED.
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Вид документа : Статья из журнала
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Автор(ы) : Liu Q., Dang P., Zhang G., Lian H., Li G., Molokeev M. S., Cheng Z., Lin J.
Заглавие : Broad luminescence tuning in Mn2+-doped Rb2Zn3(P2O7)2 via doping level control based on multiple synergies
Место публикации : CrystEngComm. - 2022. - Vol. 24, Is. 31. - P.5622-5629. - ISSN 14668033 (ISSN), DOI 10.1039/d2ce00719c
Примечания : Cited References: 31. - We acknowledge the financial support from the National Natural Science Foundation of China (NSFC No. 51932009, 51720105015, 51929201, 52072349, and 52172166), Projects for the Science and Technology Development Plan of Jilin Province (20210402046GH), and the Natural Science Foundation of Zhejiang Province (LR22E020004)
Аннотация: Here we constructed a series of novel non-centrosymmetric structure phosphors [Rb2Zn3(P2O7)2:Mn2+] by a high-temperature solid-state reaction. The multiband emission can be designed by Mn2+ preferentially occupying three types of crystallographic sites in Rb2Zn3(P2O7)2:Mn2+. The emission color could be continuously tuned from yellow-green to orange-red via multiple synergies among crystallographic site engineering, energy transfer, and Mn-Mn dimmers alone through the dopant concentration. These color-tunable phosphors have good thermal stability (I150 °C/I25 °C = 91%). The as-prepared pc-WLED has a low corresponding color temperature (CCT = 4820 K) and a high color rendering index (Ra = 90.4) with CIE color coordinates of (0.351, 0.358). These results show that emission-tunable Rb2Zn3(P2O7)2:xMn2+ phosphors are potential candidates for application in n-UV-based pc-WLED devices. This study offers a new insight for wide-range tuning of PL properties by using crystallographic site engineering through changing the doping level in Mn-activated phosphors.
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Вид документа : Статья из журнала
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Автор(ы) : Gai S. J., Zhou C., Peng L., Wu M. H., Gao P. X., Su L. J., Molokeev M. S., Zhou Z., Xia M.
Заглавие : A novel Cr3+-doped stannate far red phosphor for plant lighting: structure evolution, broad-narrow spectrum tuning and application prospect
Место публикации : Mater. Today Chem. - 2022. - Vol. 26. - Ст.101107. - ISSN 24685194 (ISSN), DOI 10.1016/j.mtchem.2022.101107
Примечания : Cited References: 50. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (Grant No. 51974123), the Distinguished Youth Foundation of Hunan Province (Grant No.2020JJ2018), the Key R & D projects in Hunan Province (2020WK2016, 2020SK2032, 2021SK2047, 2022NK2044), the Natural Science Foundation of Hunan Province, China (Grant No. 2021JJ40261), the Hunan High Level Talent Gathering Project (2019RS1077&2020RC5007), the Scientific Research Fund of Hunan Provincial Education Department (19C0903), the Natural Sciences Foundation of Hunan Agricultural University, China (Grant No. 19QN11), Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Resource Utilization Science Foundation (19KFXM12), Changsha Science and technology plan (KH2005114 and KH2201428), the Hunan Graduate Scientific Research Innovation Project (2022XC017) and the College Students' Innovative Training (S202110537012 and s202210537079x)
Аннотация: Chemical unit cosubstitution is an effective strategy to regulate the luminescence properties of phosphors, and it has attracted huge attention in the last few years. Following the design principles of the match of effective ion radius, atomic valence equilibrium and stoichiometric substitution, the local structure of crystal can be well customized, which is beneficial to develop high-performance luminescent materials. In this work, Mg2+-Sn4+ sites were cosubstituted by Zn2+-Ti4+ ion pairs in Mg2SnO4: Cr3+, respectively, and the emission spectra was successfully serially tuned from broad-band to narrow-band along with a unique variation trend of blue shift first and then slightly red shift. The photoluminescence excitation (PLE), photoluminescence (PL) spectra, lifetime decay, Raman spectra and electron paramagnetic resonance (EPR) were used to analyze the mechanism of luminescence tuning. Based on the manipulation of local structure, the as-observed distinct luminescence tuning can be well understood by the crystal field theory, nephelauxetic effect and changed Cr3+ capacity in this phosphor. Moreover, the adjusted narrow-band far-red emission spectra peak at 732 nm, matching the characteristic absorption of plant phytochrome PFR, has broad application prospects in the field of plant growth lighting. In addition, light-regulated dwarf potted tomato experiments were carried out to verify the application of far-red light in plant growth.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Yaroslavtsev R. N., Krasikov A. A., Velikanov D. A., Mikhlin Y. L., Volochaev M. N., Bayukov O. A., Stolyar S. V., Iskhakov R. S.
Заглавие : Tuning of the interparticle interactions in ultrafine ferrihydrite nanoparticles
Место публикации : Adv. Nano Res. - 2022. - Vol. 12, Is. 6. - P.605-616. - ISSN 2287237X (ISSN), DOI 10.12989/anr.2022.12.6.605
Примечания : Cited References: 73. - This study was supported by the Russian Science Foundation, project no. 21-72-00025 “Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions” (https://rscf.ru/project/21-72-00025/)
Аннотация: We prepared two samples of ultrafine ferrihydrite (FH) nanoparticle ensembles of quite a different origin. First is the biosynthesized sample (as a product of the vital activity of bacteria Klebsiella oxytoca (hereinafter marked as FH-bact) with a natural organic coating and negligible magnetic interparticle interactions. And the second one is the chemically synthesized ferrihydrite (hereinafter FH-chem) without any coating and high level of the interparticle interactions. The interparticle magnetic interactions have been tuned by modifying the nanoparticle surface in both samples. The coating of the FH-bact sample has been partially removed by annealing at 150℃ for 24 h (hereinafter FH-annealed). The FH-chem sample, vice versa, has been coated (1.0 g) with biocompatible polysaccharide (arabinogalactan) in an ultrasonic bath for 10 min (hereinafter FH-coated). The changes in the surface properties of nanoparticles have been controlled by XPS. According to the electron microscopy data, the modification of the nanoparticle surface does not drastically change the particle shape and size. A change in the average nanoparticle size in sample FH-annealed to 3.3 nm relative to the value in the other samples (2.6 nm) has only been observed. The estimated particle coating thickness is about 0.2-0.3 nm for samples FH-bact and FH-coated and 0.1 nm for sample FH-annealed. Mössbauer and magnetization measurements are definitely shown that the drastic change in the blocking temperature is caused by the interparticle interactions. The experimental temperature dependences of the hyperfine field hf(T) for samples FH-bact and FH-coated have not revealed the effect of interparticle interactions. Otherwise, the interparticle interaction energy Eint estimated from the hf(T) for samples FH-chem and FH-annealed has been found to be 121kB and 259kB, respectively.
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11.

Вид документа : Статья из журнала
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Автор(ы) : Lai S., Hu T., Molokeev M. S., Xia Z.
Заглавие : Photoluminescence tuning in Ba3ScB3O9:Eu2+ phosphor by crystal-site engineering
Место публикации : Phys. Open. - 2021. - Vol. 8. - Ст.100077. - ISSN 26660326 (ISSN), DOI 10.1016/j.physo.2021.100077
Примечания : Cited References: 31. - The present work was supported by the National Natural Science Foundation of China (Grant Nos. 51972118 and 51961145101), International Cooperation Project of National Key Research and Development Program of China (2021YFE0105700), the Guangzhou Science & Technology Project (202007020005), and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137). This work is also funded by RFBR according to the research project No. 19-52-80003
Аннотация: Controlled photoluminescence tuning is essential for optimizing and accelerating the application of phosphor materials. Here, we adopt the crystal-site engineering method to tailor the photoluminescence properties in Ba3ScB3O9:Eu2+. Ba3ScB3O9 host contains multiple cationic sites which help to finely regulate Eu2+ site occupancies and thus the emission color. The relationship between Eu2+ emission and the local environments has been analyzed, and we demonstrate that the emission colors of the phosphors can be widely tuned from NIR to yellow by chemically driving the Eu2+ from octahedrally-coordinated Sc3+ sites to nine-fold coordinated Ba2+ sites. Our study will initiate and guide more explorations on discovering new phosphors through crystal-site engineering.
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12.

Вид документа : Статья из журнала
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Автор(ы) : Kazakova M. A., Semikolenova N. V., Korovin E. Y., Zhuravlev V. A., Selyutin A. G., Velikanov D. A., Moseenkov S. I., Andreev A. S., Lapina O. B., Suslyaev V. I., Matsko M. A., Zakharov V. A., Lacaillerie J. -B.D.D.
Заглавие : Co/multi-walled carbon nanotubes/polyethylene composites for microwave absorption: Tuning the effectiveness of electromagnetic shielding by varying the components ratio
Место публикации : Compos. Sci. Technol. - 2021. - Vol. 207. - Ст.108731. - ISSN 02663538 (ISSN), DOI 10.1016/j.compscitech.2021.108731
Примечания : Cited References: 45. - This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the state assignment for Boreskov Institute of Catalysis (project # АААА-А21-121011390054-1)
Аннотация: We present novel polyethylene (PE) composites for electromagnetic interference (EMI) shielding application. They are based on cobalt modified multi-walled carbon nanotubes (MWCNTs) produced via in situ polymerization of ethylene, with the Ti-Ziegler–Natta catalyst preliminarily immobilized on Co/MWCNT hybrids. The electromagnetic properties of the composites were tuned by varying the filler loading and Co:MWCNT ratio. The microstructure of the composites and electromagnetic absorption process were carefully characterized by transmission and scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, ferromagnetic resonance and vector network analysis. The electromagnetic wave absorbing properties of the nanocomposite were investigated in the 10 MHz−18 GHz frequency range revealing that the EMI absorption properties can be tuned by varying the Co:MWCNT weight ratio in the filler. Interestingly, the Co/MWCNT-PE composite with a total filler and Co loading of only 12 and 1.7 wt%, respectively, showed extremely high reflection loss (RL) of −55 dB. More importantly, an effective bandwidth of 12.8–17.8 GHz (RL below −10 dB) was achieved for a matching thickness of only 1.5 mm. The specific RL value (RL/filler loading) of the composite was superior in comparison with the previously reported nanostructured carbon materials. The highly effective absorbing properties of Co/MWCNT-PE composites are explained primarily by the unprecedented uniform filler distribution in the polyethylene as well as by the synergistic effect of MWCNTs and Co nanoparticles. This approach thus offered an effective strategy to design cost-effective, lightweight and flexible EMI shielding materials with tunable dielectric and magnetic performance.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lai S., Zhao M., Zhao Y., Molokeev M. S., Xia Z.
Заглавие : Eu2+Doping concentration-induced site-selective occupation and photoluminescence tuning in KSrScSi2O7:Eu2+ phosphor
Место публикации : ACS. Mater. Au. - 2021. - Vol. 2, Is. 3. - P.374-380. - ISSN 26942461 (ISSN), DOI 10.1021/acsmaterialsau.1c00081
Примечания : Cited References: 43. - This work was supported by the International Cooperation Project of National Key Research and Development Program of China (2021YFE0105700), the National Natural Science Foundations of China (Grant Nos. 51972118 and 51961145101), the Guangzhou Science & Technology Project (202007020005), the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137), and the China Postdoctoral Science Foundation (2021M700298). This work was also funded by RFBR according to research project No. 19-52-80003
Аннотация: Regulation of Eu2+ dopants in different cation sites of solid-state materials is of great significance for designing multicolor phosphors for light-emitting diodes (LEDs). Herein, we report the selective occupation of Eu2+ for multiple cationic sites in KSrScSi2O7, and the tunable photoluminescence from blue to cyan is realized through Eu2+ doping concentration-dependent crystal-site engineering. Eu2+ preferably occupies the K and Sr sites in KSrScSi2O7 at a low doping concentration, resulting in a 440 nm blue emission. As the Eu2+ concentration increases, a new Eu2+ substitution pathway is triggered, that is, Eu2+ enters the Sc site, leading to the red-shifted emission spectra from 440 to 485 nm. The doping mechanism and photoluminescence properties are corroborated by structural analysis, optical spectroscopy study, and density functional theory calculations. The optical properties of the as-fabricated white LEDs are studied, which demonstrates that these phosphors can be applied to full-spectrum phosphor-converted LEDs. This study provides a new design strategy to guide the development of multicolor Eu2+-doped oxide phosphors for lighting applications.
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14.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Hoffman A. E. J., Wieme J., Senkovska I., Krylov A. S., Rogge S. M. J., Kaskel S., Speybroeck V. V.
Заглавие : Tuning terahertz vibrations to control flexibility in soft porous crystals
Коллективы : European conference on metal organic frameworks and porous polymers
Место публикации : 4th European conference on metal organic frameworks and porous polymers: Programme and book of abstracts. - 2021. - Ст.P-74 (S3P15). - ISBN 978-83-951195-7-6
Примечания : Cited References: 7
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lai S., Zhao M., Qiao J., Molokeev M. S., Xia Z.
Заглавие : Data-driven photoluminescence tuning in Eu2+-doped phosphors
Место публикации : J. Phys. Chem. Lett. - 2020. - Vol. 11, Is. 14. - P.5680-5685. - ISSN 19487185 (ISSN), DOI 10.1021/acs.jpclett.0c01471
Примечания : Cited References: 34. - The present work was supported by the National Natural Science Foundations of China (Grant No. 51972118, 51961145101 and 51722202), Fundamental Research Funds for the Central Universities (D2190980), Guangzhou Science & Technology Project (202007020005), Guangdong Provincial Science & Technology Project (No. 2018A050506004), and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137). This work is also funded by RFBR according to the research project No. 19-52-80003
Предметные рубрики: Phosphors
Luminescence properties
Crystal structure
Ions
Quantum mechanics
Аннотация: Discovery of rare earth phosphors has generally relied on the chemical intuition and time-intensive trial-and-error synthesis; therefore, finding new materials assisted by data-driven computations is urgent. Herein, we utilize a regression model to predict the emission wavelengths of Eu2+-doped phosphors by revealing the relationships between the crystal structure and luminescence property. The emission wavelengths of [Rb(1–x)K(x)]3LuSi2O7:Eu2+ (0 ≤ x ≤ 1) phosphors, as examples for the data-driven photoluminescence tuning, are successfully predicted on the basis of the existing data of only eight systems, also consistent with the experimental results. These phosphors can be excited by blue light and exhibit broad-band red and near-infrared emission ranging from 619 to 737 nm. These findings in Eu2+-doped silicate phosphors indicate that data-driven computations through the regression mode would have bright application in discovering novel phosphors with a target emission wavelengths.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gai S., Zhu H., Gao P., Zhou C., Kong Z., Molokeev M. S., Qi Z., Zhou Z., Xia M.
Заглавие : Structure analysis, tuning photoluminescence and enhancing thermal stability on Mn4+-doped La2-xYxMgTiO6 red phosphor for agricultural lighting
Место публикации : Ceram. Int. - 2020. - Vol. 46, Is. 12. - P.20173-20182. - ISSN 02728842 (ISSN), DOI 10.1016/j.ceramint.2020.05.095
Примечания : Cited References: 40. - The authors would like to gratefully acknowledge funds from the National Natural Science Foundation of China (Grant No. 21706060 , 51703061 , 51974123 ), the Hunan Graduate Research and Innovation Project (Grant No. CX2018B396 ), the Hunan provincial Engineering Technology Research Center for Optical Agriculture (Grant No. 2018TP2003 ), the Scientific Research Fund of Hunan Provincial Education Department (15K058, 19C0903), the Natural Sciences Foundation of Hunan agricultural university, China (Grant No. 19QN11), the Science and Technology project of Changsha (KH1801219) and the Huxiang high level talent gathering project (2019RS1077)
Аннотация: Currently, phosphor-converted LEDs (pc-LEDs) are revolutionizing the industry of plant growth lighting. To meet the requirements of this technology, phosphors with tunable photoluminescence, high thermal stability and luminous intensity are required. Herein, we found that the simple substitution of yttrium for lanthanum in La2MgTiO6:Mn4+ (LMT:Mn4+) system could satisfy above three criteria simultaneously. The photoluminescence properties can be regulated by continuously controlling the chemical composition of La2-xYxMgTiO6:Mn4+ solid solution. The La sites are occupied by Y ions, causing a significant blue shift in the emission spectra which owing to the change of local crystal field strengthen. Meanwhile, the thermal stability and decay lifetimes are also varied due to the variation of local structure and band gap energy. The thermal stability of the material reaches 83.5% at 150 °C, which is better than the reported La2MgTiO6:Mn4+ and Y2MgTiO6:Mn4+ phosphors. The electronic luminescence (EL) of pc-LED devices using La2-xYxMgTiO6:Mn4+ red phosphor is evaluated, which matching the absorption regions of plant pigments well, reflecting the superiority of the studied phosphors in plant growth lighting areas.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Liu, Dongjie, Yun, Xiaohan, Li, Guogang, Dang, Peipei, Molokeev M. S., Lian, Hongzhou, Shang, Mengmeng, Lin, Jun
Заглавие : Enhanced cyan emission and optical tuning of Ca3Ga4O9:Bi3+ for high-quality full-spectrum white light-emitting diodes
Место публикации : Adv. Opt. Mater. - 2020. - Vol. 8, Is. 22. - Ст.2001037. - ISSN 2195-1071, DOI 10.1002/adom.202001037
Примечания : Cited References: 55. - This work was financially supported by the National Natural Science Foundation of China (NSFC No. 51932009, 51720105015, 51672265, 51672266, 51672257 and 51672259), the Key Research Program of Frontier Sciences, CAS (Grant No. YZDY-SSW-JSC018), Science and Technology Cooperation Project between Chinese and Australian Governments (2017YFE0132300), the Jiangmen Innovative Research Team Program (2017), and the Major Program of Basic Research and Applied Research of Guangdong Province (2017KZDXM083)
Предметные рубрики: ENERGY-TRANSFER
TUNABLE LUMINESCENCE
PHOSPHOR
CRYSTAL
MODULATION
Аннотация: Highly efficient cyan‐emitting phosphor materials are indispensable for closing the cyan gap in spectra of the traditional phosphor‐converted white light‐emitting diodes (WLEDs) to achieve high‐quality full‐spectrum white lighting. In this work, bright cyan‐emitting Ca3Ga4O9 (CGO):0.02Bi3+,0.07Zn2+ phosphor is developed to bridge the cyan gap. Such a Bi3+,Zn2+ codoping enhances the cyan emission of CGO:0.02Bi3+ by 4.1 times due to the influence of morphology and size of phosphor particles, charge compensation and lattice distortion. Interestingly, codoping La3+ ions into the current system can achieve a photoluminescence tuning of CGO:0.02Bi3+ from cyan to yellowish‐green by crystallographic site engineering. Besides, Bi3+–Eu3+ energy transfer is successfully realized in CGO:0.02Bi3+,0.07Zn2+,nEu3+ phosphors and the emission color tuning from cyan to orange is observed. The investigation of thermal quenching behaviors reveals that the incorporation of Zn2+ and La3+ improves the thermal stability of CGO:0.02Bi3+. Finally, CGO:0.02Bi3+,0.07Zn2+,0.10Eu3+ phosphor is employed to obtain a single‐phased warm WLED device. A full‐spectrum WLED device with remarkable color rendering index (Ra) of 97.4 and high luminous efficiency of 69.72 lm W−1 is generated by utilizing CGO:0.02Bi3+,0.07Zn2+ phosphor. This result suggests the important effect of CGO:0.02Bi3+,0.07Zn2+ phosphor on closing the cyan gap, providing new insights of cyan‐emitting phosphors applied in full‐spectrum white lighting.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sukhikh, Taisiya S., Khisamov, Radmir M., Bashirov D. A., Komarov, Vladislav Yu, Molokeev M. S., Ryadun, Alexey A., Benassi E., Konchenko, Sergey N.
Заглавие : Tuning of the coordination and emission properties of 4-amino-2,1,3-benzothiadiazole by introduction of diphenylphosphine group
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [19-73-00030]; RFBRRussian Foundation for Basic Research (RFBR) [19-52-80003]
Место публикации : Cryst. Growth Des. - 2020. - Vol. 20, Is. 9. - P.5796-5807. - ISSN 1528-7483, DOI 10.1021/acs.cgd.0c00406. - ISSN 1528-7505(eISSN)
Примечания : Cited References: 58. - This work is supported by the Russian Science Foundation (project no. 19-73-00030) and partly by RFBR (viz., powder XRD data processing and determination of the structure of 1. CINF7/INFHINF8/INF using powder XRD) according to the research project no. 19-52-80003. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and thank Prof. Andrew N. Fitch. We are grateful to Siberian Supercomputer Centre of Institute of Computational Mathematics and Mathematical Geophysics for computational capability and thank the technical staff of the Institute for the assistance
Предметные рубрики: COMPLEXES
BENZOTHIADIAZOLE
CHEMISTRY
SUBSTITUENTS
LIGANDS
PROGRAM
Аннотация: A novel amino-benzothiadiazole bearing diphenylphosphine groups (L) was designed and synthesized. A number of its coordination compounds of Cu(I) (1·0.75C7H8, 2a,b), Pd(II) (4), and Pt(II) (5) were prepared demonstrating the coordination of L ligand via N and/or P atoms. The reaction with strong Lewis acid Zn(II) resulted in the rearrangement of P—N—P to P–P–N moiety and formation of complex 3. The structures of L, 2–5 were determined by single crystal X-ray (XRD) diffraction, while that of 1·0.75C7H8 was determined by powder XRD analysis. Intermolecular secondary bonding of S···S interactions in the compounds, unusual for benzothiadiazoles, was discussed supported by quantum chemical calculations. Differences in the structures of the compounds cause significant changes of photophysical properties. In particular, the position of the electronic absorption band is featured by the conformation of L, viz., the dihedral angle between the benzothiadiazole unit and the P—N—P moiety, as proved by TD-DFT calculations performed on model molecules. The photophysical properties of the compounds also strongly depend on the coordination mode of L: the presence of a bond between the metal and the N atom of the thiadiazole unit plays an essential role in defining the position of the absorption and emission bands as well as emission lifetime of these compounds. The thermally activated delayed fluorescence and phosphorescence mechanisms in a thermal equilibrium were determined for 1·0.75C7H8. Complex 5 features a broad emission band spanning the entire visible region; moreover, it shows an unusual clear-white luminescence, which remains visible even in the daylight.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhao M., Xia Z., Huang X., Ning L., Gautier R., Molokeev M. S., Zhou Y., Chuang Y. -C., Zhang Q., Liu Q., Poeppelmeier K. R.
Заглавие : Li substituent tuning of LED phosphors with enhanced efficiency, tunable photoluminescence, and improved thermal stability
Место публикации : Science Adv. - 2019. - Vol. 5, Is. 1. - Ст.eaav0363. - ISSN 2375-2548, DOI 10.1126/sciadv.aav0363
Примечания : Cited References: 38. - This research was supported by the National Natural Science Foundation of China (nos. 51722202, 91622125, 51572023, and 11574003) and Natural Science Foundations of Beijing (2172036), and this work was also supported by funding from the National Science Foundation (award DMR-1608218) and French National Agency for Research (ANR Young Researchers: ANR-16-CE08-0003-01).
Предметные рубрики: MATERIALS SCIENCE
Аннотация: Solid-state phosphor-converted white light-emitting diodes (pc-WLEDs) are currently revolutionizing the lighting industry. To advance the technology, phosphors with high efficiency, tunable photoluminescence, and high thermal stability are required. Here, we demonstrate that a simple lithium incorporation in NaAlSiO4:Eu system enables the simultaneous fulfillment of the three criteria. The Li substitution at Al sites beside Na sites in NaAlSiO4:Eu leads to an enhanced emission intensity/efficiency owing to an effective Eu3+ to Eu2+ reduction, an emission color tuning from yellow to green by tuning the occupation of different Eu sites, and an improvement of luminescence thermal stability as a result of the interplaywith Li-related defects. A pc-WLED using the Li-codoped NaAlSiO4:Eu as a green component exhibits improved performance. The phosphorswithmultiple activator sites can facilitate the positive synergistic effect on luminescence properties.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou, Guojun, Jiang, Xingxing, Zhao, Jing, Molokeev M. S., Lin, Zheshuai, Liu, Quanlin, Xia, Zhiguo
Заглавие : Two-dimensional-layered perovskite ALaTa2O7:Bi3+ (A = K and Na) phosphors with versatile structures and tunable photoluminescence
Место публикации : ACS Appl. Mater. Interfaces. - 2018. - Vol. 10, Is. 29. - P.24648-24655. - ISSN 1944-8244, DOI 10.1021/acsami.8b08129
Примечания : Cited References: 48. - The authors acknowledge the support from the National Natural Science Foundation of China (Nos. 51722202, 91622125, and 51572023) and the Natural Science Foundations of Beijing (2172036) and RFBR (17-52-53031).
Предметные рубрики: GENERALIZED GRADIENT APPROXIMATION
YELLOW-EMITTING PHOSPHOR
Ключевые слова (''Своб.индексиров.''): 2d-layered perovskite--bi3+ emission--ion exchange--photoluminescence tuning--white light leds
Аннотация: Topological chemical reaction methods are indispensable for fabricating new materials or optimizing their functional properties, which is particularly important for two-dimensional (2D)-layered compounds with versatile structures. Herein, we demonstrate a low-temperature (∼350 °C) ion exchange approach to prefabricate metastable phosphors ALa1–xTa2O7:xBi3+ (A = K and Na) with RbLa1–xTa2O7:xBi3+ serving as precursors. The as-prepared ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) share the same Dion–Jacobson type 2D-layered perovskite phase, and photoluminescence analyses show that ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) phosphors exhibit broad emission bands peaking at 540, 550, and 510 nm, respectively, which are attributed to the nonradiative transition of Bi3+ from excited state 3P1 or 3P0 to ground state 1S0. The various Bi3+ local environments at the crystallographic sites enable the different distributions of emission and excitation spectra, and the photoluminescence tuning of ALa0.98Ta2O7:0.02 Bi3+ (A = Rb, K, and Na) phosphors are realized through alkali metal ion exchange. Notably, the combination of superior trivalent bismuth emission and low-temperature ion exchange synthesis leads to a novel yellow-emitting K(La0.98Bi0.02)Ta2O7 phosphor which is successfully applied in a white LED device based on a commercially available 365 nm LED chip. Our realizable cases of this low-temperature ion exchange strategy could promote exploration into metastable phosphors with intriguing properties.
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