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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H. P., Huang Z. H., Xia, Zhiguo, Molokeev M. S., Atuchin V. V., Huang S. F.
Заглавие : Cation substitution dependent bimodal photoluminescence in whitlockite structural Ca3-xSrx(PO4)2:Eu2+ (0 ≤ x ≤ 2) solid solution phosphors
Место публикации : Inorg. Chem.: American Chemical Society, 2014. - Vol. 53, Is. 20. - P.11119-11124. - ISSN 0020-1669, DOI 10.1021/ic501679f. - ISSN 1520-510X
Примечания : Cited References: 37. - This work was supported by the National Natural Science Foundations of China (Grant Nos. 51032007, 51002146, 51272242), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130022110006), the Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), and Beijing Youth Excellent Talent Program (YETP0635). V.V.A. acknowledges the Ministry of Education and Science of the Russian Federation for financial support.
Предметные рубрики: LIGHT-EMITTING-DIODES
EFFICIENT ENERGY-TRANSFER
EMISSION-TUNABLE PHOSPHOR
EXCITED WHITE LEDS
CRYSTAL-STRUCTURE
LUMINESCENCE PROPERTIES
Mn2+ PHOSPHOR
COLOR TONE
PHASE
Eu2+
Аннотация: Cation substitution dependent tunable bimodal photoluminescence behavior was observed in the Ca3-xSrx(PO4)2:Eu2+ (0 ≤ x ≤ 2) solid solution phosphors. The Rietveld refinements verified the phase purity and whitlockite type crystal structure of the solid solutions. The tunable photoluminescence evolution was studied as a function of strontium content, over the composition range 0.1 ≤ x ≤ 2. In addition to the emission band peak at 416 nm in Ca3(PO4)2:Eu2+, the substitution of Ca2+ by Sr2+ induced the emerging broad-band peak at 493-532 nm. A dramatic red shift of the emission peak located in the green-yellow region was observed on an increase of x in the samples with 0.75 ≤ x ≤ 2.00. The two emission bands could be related to the EuOn-Ca9 and EuOn-Ca9-xSrx emitting blocks, respectively. The values for the two kinds of emitting blocks in the solid solutions can be fitted well with the observed intensity evolution of the two emission peaks.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang Z. Y., Xia, Zhiguo, Molokeev M. S., Atuchin V. V., Liu Q. L.
Заглавие : Blue-shift of Eu2+ emission in (Ba,Sr)3Lu(PO4)3:Eu2+ eulytite solid-solution phosphors resulting from release of neighbouring-cation-induced stress
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2014. - Vol. 43, Is. 44. - P.16800-16804. - ISSN 1477-9226, DOI 10.1039/c4dt02319f. - ISSN 1477-9234
Примечания : Cited References: 16. - The present work was supported by the National Natural Science Foundations of China (grant no. 51002146, no. 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in the University of the Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635) and the Funds of the State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University (KF201306). V.V.A. is partly supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: TUNABLE COLOR TONE
EXCITED WHITE LEDS
CRYSTAL-STRUCTURE
TEMPERATURE
IONS
Аннотация: A series of iso-structural eulytite-type (Ba,Sr)(3)Lu(PO4)(3):Eu2+ solid-solution phosphors with different Sr/Ba ratios were synthesized by a solid-state reaction. Crystal structures of (Ba,Sr)(3)Lu(PO4)(3):Eu2+ were resolved by the Rietveld method, which shows an eulytite-type cubic Bi-4(SiO4)(3) structure with cations disordered in a single C-3 site while the oxygen atoms were distributed over two partially occupied sites. The emission peaks of Ba(3-x)SrxLu(PO4)(3):Eu2+ (0
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H. P., Huang Z. H., Xia Z. G., Molokeev M. S., Atuchin V. V., Fang M. H., Huang S. F.
Заглавие : New yellow-emitting whitlockite-type structure Sr1.75Ca 1.25(PO4)2:Eu2+ phosphor for near-UV pumped white light-emitting devices
Место публикации : Inorg. Chem.: American Chemical Society, 2014. - Vol. 53, Is. 10. - P.5129-5135. - ISSN 0020-1669, DOI 10.1021/ic500230v. - ISSN 1520-510X
Примечания : Cited References: 31. - This work was supported by the National Natural Science Foundations of China (Grant Nos. 51032007, 51002146, 51272242), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130022110006), and the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950). V.V.A. gratefully acknowledges the Ministry of Education and Science of the Russian Federation for the financial support. S.H. would like to acknowledge the China Scholarship Council (CSC) for providing a doctoral scholarship for his Ph.D. study at the University of Auckland.
Предметные рубрики: LUMINESCENCE PROPERTIES
CRYSTAL-STRUCTURE
RED PHOSPHOR
DIODES
LEDS
SR
CA
ORTHOPHOSPHATE
CA-3(PO4)2
EUROPIUM
Аннотация: New compound discovery is of interest in the field of inorganic solid-state chemistry. In this work, a whitlockite-type structure Sr1.75Ca1.25(PO4)2 newly found by composition design in the Sr3(PO4)2–Ca3(PO4)2 join was reported. Crystal structure and luminescence properties of Sr1.75Ca1.25(PO4)2:Eu2+ were investigated, and the yellow-emitting phosphor was further employed in fabricating near-ultraviolet-pumped white light-emitting diodes (w-LEDs). The structure and crystallographic site occupancy of Eu2+ in the host were identified via X-ray powder diffraction refinement using Rietveld method. The Sr1.75Ca1.25(PO4)2:Eu2+ phosphors absorb in the UV–vis spectral region of 250–430 nm and exhibit an intense asymmetric broadband emission peaking at 518 nm under λex = 365 nm which is ascribed to the 5d–4f allowed transition of Eu2+. The luminescence properties and mechanism are also investigated as a function of Eu2+ concentration. A white LED device which is obtained by combining a 370 nm UV chip with commercial blue phosphor and the present yellow phosphor has been fabricated and exhibit good application properties.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yu, Shixin, Xia, Zhiguo, Molokeev M. S., Miao, Hao, Atuchin V. V.
Заглавие : Synthesis and luminescence properties of blue-emitting phosphor Li3c2(PO4)3:Er2+
Место публикации : ECS J. Solid State Sci. Technol. - 2014. - Vol. 3, Is. 8. - P.R159-R163. - ISSN 2162-8769, DOI 10.1149/2.0071408jss. - ISSN 2162-8777
Примечания : Cited References: 33. - The present work was supported by the National Natural Science Foundations of China (Grant No. 51002146, No. 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in the University of the Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635) and the Funds of the State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University (KF201306). Z. G. Xia is also grateful for the financial support from University of Science and Technology Beijing. V.V.A. gratefully acknowledge the Ministry of Education and Science of the Russian Federation for the financial support.
Предметные рубрики: ENERGY-TRANSFER
PHOTOLUMINESCENCE PROPERTIES
INORGANIC-COMPOUNDS
EMISSION COLOR
FULL-COLOR
DIODES
Eu2+
IONS
LEDS
Tb
Аннотация: A new blue-emitting phosphor Li3Sc2(PO4)3:Eu2+ was synthesized by a high temperature solid-state reaction method, and the crystal structure and photoluminescence properties were investigated in detail. The preferred crystallographic position of the Eu2+ ions in the Li3Sc2(PO4)3 host were determined from the structural analysis and spectroscopic properties. The as-prepared phosphor gave an intense blue emission band centered at 439 nm with the CIE coordinate of (0.1540, 0.0317) upon the excitation of the near ultraviolet light. The critical quenching concentration of Eu2+ in Li3Sc2(PO4)3:Eu2+ was about 15 mol%, and the corresponding concentration quenching mechanism was verified to be the dipole-quadrupole interaction. The fluorescence lifetime of Eu2+ emission and the thermal stable luminescence property have been investigated. Li3Sc2(PO4)3:Eu2+ was found to be a promising candidate as a blue-emitting n-UV convertible phosphor for the application in white light emitting diodes (w-LEDs).
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lim, Chang Sung, Atuchin V. V., Aleksandrovsky A. S., Molokeev M. S., Oreshonkov A. S.
Заглавие : Microwave sol–gel synthesis of CaGd2(MoO4)4:Er3+/Yb3+ phosphors and their upconversion photoluminescence properties
Место публикации : J. Am. Ceram. Soc.: Wiley-Blackwell, 2015. - Vol. 98, Is. 10. - P.3223-3230. - ISSN 0002, DOI 10.1111/jace.13739. - ISSN 15512916(eISSN)
Примечания : Cited References:69. - This study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2014-046024). VVA and ASA are partially supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: RED-EMITTING PHOSPHORS
VIBRATIONAL PROPERTIES
LUMINESCENCE PROPERTIES
WHITE LEDS
SPECTROSCOPIC PROPERTIES
HYDROTHERMAL SYNTHESIS
CRYSTAL-STRUCTURE
ROOM-TEMPERATURE
ENERGY-TRANSFER
SR
Аннотация: CaGd2(MoO4)4:Er3+/Yb3+ phosphors with the doping concentrations of Er3+ and Yb3+ (x = Er3+ + Yb3+, Er3+ = 0.05, 0.1, 0.2, and Yb3+ = 0.2, 0.45) have been successfully synthesized by the microwave sol–gel method, and the crystal structure refinement and upconversion photoluminescence properties have been investigated. The synthesized particles, being formed after heat-treatment at 900°C for 16 h, showed a well-crystallized morphology. Under the excitation at 980 nm, CaGd2(MoO4)4:Er3+/Yb3+ particles exhibited strong 525 and 550-nm emission bands in the green region and a weak 655-nm emission band in the red region. The Raman spectrum of undoped CaGd2(MoO4)4 revealed about 15 narrow lines. The strongest band observed at 903 cm−1 was assigned to the ν1 symmetric stretching vibration of MoO4 tetrahedrons. The spectra of the samples doped with Er and Yb obtained under 514.5 nm excitation were dominated by Er3+ luminescence preventing the recording Raman spectra of these samples. Concentration quenching of the erbium luminescence at 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions in the CaGd2(MoO4)4:Er3+/Yb3+ crystal structure was established to be approximately at the 10 at.% doping level.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhu J., Xia, Zhiguo, Zhang Y., Molokeev M. S., Liu Q.
Заглавие : Structural phase transitions and photoluminescence properties of Eu3+ doped Ca(2-x)BaxLaNbO6 phosphors
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2015. - Vol. 44, Is. 42. - P.18536-18543. - ISSN 1477-9226, DOI 10.1039/c5dt03430b
Примечания : Cited References: 27. - The present work was supported by the National Natural Science Foundation of China (Grant No. 51272027, 51472028 and 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in the University of the Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635), and the Funds of the State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University (KF201306)
Предметные рубрики: Double-perovskite
Luminescence properties
Thermal-stability
Crystal-chemistry
Red phosphors
White LEDs
Symmetry
Band
Ta
Ln
Аннотация: Crystal structures of the series of double perovskites Ca(2-x)BaxLaNbO6:Eu3+ phosphors have been examined by powder X-ray diffraction and Rietveld refinements. Ca2LaNbO6 has a monoclinic (P21/n) and Ba2LaNbO6 has a monoclinic (C2/m) structure. The structural phases of Ca(2-x)BaxLaNbO6:Eu3+ samples are divided into three sections depending on different Ca/Ba ratios: (1) monoclinic phase (P21/n) as Ca2LaNbO6 in the range of x = 0-0.1, (2) mixed phases containing Ca2LaNbO6 and Ba2LaNbO6 between 0.15 and 1.2, and (3) monoclinic phase (C2/m) as Ba2LaNbO6 for x = 1.4-2. Eu3+ ions act as the structural probes to study the structural phase transitions, and the evolution of the photoluminescence properties and thermal stability behaviours has been also comparatively investigated depending on different structural symmetries from Ca2LaNbO6 to Ba2LaNbO6 phase. The strong red emission from 5D0-7F2 peaking at 618 nm can be found in Ca2LaNbO6:Eu3+ phosphors, which is attributed to the low crystal field effect of the activator ions located in the highly distorted [Lao8] polyhedra sites. The composition-optimized phosphors can find applications in white light emitting diodes (LEDs).
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Cheng F., Xia, Zhiguo, Molokeev M. S., Jing X.
Заглавие : Effects of composition modulation on the luminescence properties of Eu3+ doped Li1-xAgxLu(MoO4)2 solid-solution phosphors
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2015. - Vol. 44, Is. 41. - P.18078-18089. - ISSN 1477-9226, DOI 10.1039/c5dt02760h
Примечания : Cited References: 42. - The present work was supported by the National Natural Science Foundations of China (Grant No. 51272242, 51572023, 51511130035), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635), the Funds of the State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (RERU2015022), and the excellent tutor section of the Fundamental Research Funds for the Central Universities of China University of Geosciences, Beijing (2-9-2015-028). This work was also partly supported by the Russian Foundation for Basic Research (Grant No. 15-52-53080 GFEN_a).
Предметные рубрики: RED PHOSPHORS
PHOTOLUMINESCENCE PROPERTIES
ENERGY-TRANSFER
WHITE LEDS
IONS
NA
POLYMORPHISM
TUNGSTATES
RELAXATION
MOLYBDATES
Аннотация: Double molybdate scheelite-type solid-solution phosphors Li1−xAgxLu1−y(MoO4)2:yEu3+ were synthesized by the solid state reaction method, and their crystal structures and luminescence properties were investigated in detail. The composition modulation and structural evolution of this series of samples were studied and the selected AgEu(MoO4)2, AgLu(MoO4)2, LiLu(MoO4)2 and LiEu(MoO4)2 phases were analyzed based on the Rietveld refinement. Depending on the variation of the Li/Ag ratio in Li1−xAgxLu1−y(MoO4)2:yEu3+ phosphors, the difference in the luminescence properties of Li1−xAgxLu1−y(MoO4)2:yEu3+ phosphors was ascribed to two factors, one reason could be assigned to the coupling effect and the nonradiative transition between the energy levels of LixAg1−xLu(MoO4)2 matrices and the activator Eu3+, another could be due to the near ultraviolet energy absorption and transmission efficiency between the charge-transfer (CT) band of O2−–Mo6+ and the 4f → 4f emissive transitions of Eu3+. The ultraviolet-visible diffuse reflection spectra (UV-vis DRS) and Raman spectra analysis were also used to verify the above mechanism.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou, Jun, Xia, Zhiguo, Chen, Mingyue, Molokeev M. S., Liu, Quanlin
Заглавие : New insight into phase formation of MxMg2Al4+xSi5-xO18:Eu2+ solid solution phosphors and its luminescence properties
Место публикации : Sci. Rep. - 2015. - Vol. 5. - Ст.12149. - ISSN 2045-2322, DOI 10.1038/srep12149
Примечания : Cited References:17. - The present work was supported by the National Natural Science Foundations of China (Grant No. 51002146, No. 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635), the Funds of the State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University (KF201306), and Fundamental Research Funds for the Central Universities (FRF-TP-14-005A1).
Предметные рубрики: CRYSTAL-STRUCTURE
ENERGY-TRANSFER
WHITE LEDS
CORDIERITE
Eu2+
Mg2Al4Si5O18
EMISSION
Аннотация: Here we reported the phase formation of MxMg2Al4+xSi5-xO18:Eu2+ (M = K, Rb) solid solution phosphors, where M+ ions were introduced into the void channels of Mg2Al4Si5O18 via Al3+/Si4+ substitution to keep the charge balance. XRD results revealed that the as-prepared phosphors with different M+ contents were iso-structural with Mg2Al4Si5O18 phase. The combined analysis of the Rietveld refinement and high resolution transmission electron microscopy (HRTEM) results proved that M+ ions were surely introduced into the intrinsic channels in Mg2Al4Si5O18. The emission peaks of MxMg2Al4+xSi5-xO18:Eu2+ (M = K, Rb) phosphors with various x values performed a systematic red-shift tendency, which was ascribed to the elongation of [MgO6] octahedra. The temperature stable photoluminescence and internal quantum efficiency (QE) of MxMg2Al4+xSi5-xO18:Eu2+ (M = K, Rb) phosphors were enhanced owing to the filling of M+ in the void channels suggesting a new insight to design the solid solution phosphors with improved photoluminescence properties.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Guo Q., Liao L., Molokeev M. S., Mei L., Liu H.
Заглавие : Color tunable emission and energy transfer of Ce3+ and Tb3+ co-doped novel La6Sr4(SiO4)6F2 phosphors with apatite structure
Место публикации : Mater. Res. Bull.: Elsevier, 2015. - Vol. 72. - P.245-251. - ISSN 0025-5408, DOI 10.1016/j.materresbull.2015.07.029
Примечания : Cited References: 37. - This present work is supported by the National Natural Science Foundations of China (Grant No. 41172053).
Предметные рубрики: LIGHT-EMITTING-DIODES
LUMINESCENCE PROPERTIES
PHOTOLUMINESCENCE PROPERTIES
EU2+
LEDS
Ключевые слова (''Своб.индексиров.''): inorganic compounds--luminescence--phosphors--optical properties--crystal structure
Аннотация: Single-phase La6Sr4(SiO4)6F2: Ce3+, Tb3+ samples with apatite-like structure have been synthesized via solid-state reaction method. The phase structure, luminescence properties, lifetime, the PL thermal stability, as well as the fluorescence decay curves of the samples were investigated to characterize the resulting samples. Effective energy transfer occurs from Ce3+ to Tb3+ in La6Sr4(SiO4)6F2, which shows more intense Blue-Green light under UV light excitation. In addition, a possible mechanism of the energy-transfer from Ce3+ to Tb3+ ion is also proposed. The critical distance RC of Ce3+ to Tb3+ ions in La6Sr4(SiO4)6F2 host was calculated to be 11.878 Å. All the results indicate that La6Sr4(SiO4)6F2:Ce3+, Tb3+ phosphors have potential applications to be used as near UV-convertible phosphors for white light-emitting diodes. © 2015 Elsevier Ltd. All rights reserved.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Guo Q. F., Ma B., Liao L. B., Molokeev M. S., Mei L. F., Liu H. K.
Заглавие : Crystal structure and luminescence properties of novel Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphor with apatite structure
Место публикации : Ceram. Int.: Elsevier Science, 2016. - Vol. 42, Is. 10. - P.11687-11691. - ISSN 0272-8842, DOI 10.1016/j.ceramint.2016.04.086. - ISSN 1873-3956(eISSN)
Примечания : Cited References:26. - This present work is supported by the National Natural Science Foundation of China (Grant no. 41172053).
Предметные рубрики: Light-Emitting-Diodes
Energy-transfer
Tunable phosphor
LEDs
Eu-2+
Ions
Ce3+
Ключевые слова (''Своб.индексиров.''): crystal structure--apatite--phosphor
Аннотация: In this paper, a series of novel luminescent Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors with apatite structure were synthesized by a high temperature solid-state reaction. The phase structure, photoluminescence (PL) properties, as well as the PL thermal stability were investigated. Sr9.92(SiO4)3(SO4)3O:0.08Eu2+ phosphor exhibits better thermal quenching resistance, retaining the luminance of 66.55% at 150 °C compared with that at 25 °C. The quenching concentration of Eu2+ in Sr10(SiO4)3(SO4)3O was about 0.08 (mol) with the dipole–quadrupole interaction. The Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors exhibited a broad-band green emission at 538 nm upon excitation at 396 nm. The results indicate that Sr10−x(SiO4)3(SO4)3O:xEu2+ phosphors have potential applications as near UV-convertible phosphors for white-light UV LEDs.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wei Y., Lin C. C., Quan Z., Molokeev M. S., Atuchin V. V., Chan T. -S., Liang Y., Lin J., Li G.
Заглавие : Structural evolution induced preferential occupancy of designated cation sites by Eu2+ in M5(Si3O9)2 (M = Sr, Ba, Y, Mn) phosphors
Место публикации : RSC Adv.: Royal Society of Chemistry, 2016. - Vol. 6, Is. 62. - P.57261-57265. - ISSN 20462069 (ISSN), DOI 10.1039/c6ra11681g
Примечания : Cited References: 28. - This project is financially supported by the National Natural Science Foundation of China (Grants No. NSFC 21301162, 21571162, 60977013, 91433110, U1301242, 21221061), the National College Students' Innovative Training Program (Nos. 201510491109, 201610491067, 201610491070), and the Ministry of Science and Technology of Taiwan (No. MOST 104-2917-1-564-060). Zewei Quan acknowledges the funding support (FRG-SUSTC1501A-17) from South University of Science and Technology of China.
Предметные рубрики: LUMINESCENCE PROPERTIES
RED LUMINESCENCE
UP-CONVERSION
WHITE LEDS
PHOTOLUMINESCENCE
NANOPHOSPHORS
YELLOW
WLEDS
Аннотация: In this paper, we present new insight into a changing Eu2+ crystallographic site preference in Eu-doped M5(Si3O9)2 (M = Sr, Ba, Y, Mn), which is related to the structural variation induced by M cation substitutions. The effect of the local structural geometry on the luminescence properties of Eu2+ is revealed. By substitution of Ba2+ for Sr2+, the lattice expansion is restricted to specific cation sites, resulting in the abrupt blue shifted emission of Eu2+ ions. The abnormal blue shift on replacing Sr2+ with Mn2+ is attributed to the preferential 6-fold coordination for Mn2+ that moves the Eu2+ ions to other sites. The results elucidate the mechanisms of emission band adjustment by local site coordination change and it can be potentially extended to crystals which properties are sensitive to local lattice variations. © 2016 The Royal Society of Chemistry.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H., Wang L., Molokeev M. S., Hirosaki N., Xie R., Huang Z., Xia Z., Ten Kate O. M., Liu L., Atuchin V. V.
Заглавие : Structure evolution and photoluminescence of Lu3(Al,Mg)2(Al,Si)3O12:Ce3+ phosphors: New yellow-color converters for blue LED-driven solid state lighting
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 28. - P.6855-6863. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc00966b
Примечания : Cited References: 44. - This work was partially supported by the National Natural Science Foundations of China (Grant No. 51511130035, 51272259, 61575182, 51561135015, and 51572232) and the Russian Foundation for Basic Research (Grant No. 15-52-53080). We are also grateful to financial support from the JSPS KAKENHI (No. 15K06448). H. J. thanks the China Scholarship Council (CSC) for scholarship support. V. V. A. was partially supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: WHITE LEDS
LUMINESCENCE PROPERTIES
EMITTING-DIODES
GARNET PHOSPHORS
SUBSTITUTION
Ce3+
PHASE
Ca
Аннотация: This paper reports the development of new phosphors using the chemical unit cosubstituting solid solution design strategy. Starting from Lu3Al5O12, the Al3+-Al3+ couple in respective octahedral and tetrahedral coordination was simultaneously substituted by a Mg2+-Si4+ pair forming the Lu3(Al2-xMgx)(Al3-xSix)O12:Ce3+ (x = 0.5-2.0) series; as a result, the CeO8 polyhedrons were compressed and the emission got red-shifted from green to yellow together with the broadening. The evolution of, the unit cell, the local structural geometry as well as the optical properties of Ce3+ in these garnet creations, in response to the gradual Mg-Si substitution for Al-Al, were studied by combined techniques of structural refinement and luminescence measurements. The new composition Lu2.97Ce0.03Mg0.5Al4Si0.5O12 was comprehensively evaluated regarding its potential application in blue LED-driven solid state white lighting: the maximum emission is at 550 nm under ?ex = 450 nm; the internal and external quantum efficiencies can reach 85% and 49%, respectively; a 1-phosphor-converted wLED lamp fabricated using the as-prepared phosphor exhibits the luminous efficacy of 105 lm W-1, the correlated color temperature of 6164 K and the color rendering index (Ra) of 75.6. The new solid solution composition series is open for further optimization to enhance the competence for commercial consideration. © 2016 The Royal Society of Chemistry.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia Y. F., Liu Y. G., Huang Z. H., Fang M. H., Molokeev M. S., Mei L. F.
Заглавие : Ca6La4(SiO4)2(PO4)4O2:Eu2+: a novel apatite green-emitting phosphor for near-ultraviolet excited w-LEDs
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 21. - P.4675-4683. - ISSN 2050-7526, DOI 10.1039/c6tc01418f. - ISSN 2050-7534(eISSN)
Примечания : Cited References:37. - This study was sponsored by the National Natural Science Foundation of China (Grant No. 51472223), the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-12-0951) and the Fundamental Research Funds for the Central Universities (Grant No. 2652015020 and Grant No. 2652015008).
Предметные рубрики: SOLID-SOLUTION PHOSPHORS
PULSED-LASER DEPOSITION
HIGH THERMAL-STABILITY
WHITE-LIGHT
LUMINESCENCE PROPERTIES
ENERGY-TRANSFER
SINGLE-PHASE
CRYSTAL-STRUCTURE
RED LUMINESCENCE
EPITAXIAL-GROWTH
Аннотация: A novel apatite phosphor Ca6La4(SiO4)2(PO4)4O2:Eu2+ was prepared by conventional high-temperature solid-state reaction. Phase purity was examined by XRD and XPS analysis. The crystal structure information, such as space group, cell parameters and atomic coordinates, were refined by the Rietveld method, revealing that Eu2+ occupied the sites of Ca2+ ions. Moreover, low-temperature experiments, including low-temperature PL spectra and low-temperature decay curve, were used to prove the existence of two luminescence centers in Ca6La4(SiO4)2(PO4)4O2:Eu2+. With the increase in doping concentration of Eu2+, the emission wavelength shows a red shift from 498 nm to 510 nm, which is mainly caused by the increase in crystal-field splitting by Eu2+. The optimized concentration of Eu2+ was confirmed to be 0.01, the Rc was calculated to be 20.09 Å and the energy transfer between Eu2+ was demonstrated to be by exchange interaction. Moreover, good thermal stability has been proved by a temperature-dependence experiment; it shows that the phosphor can maintain 55% of emitting intensity at 150 °C compared to that at room temperature. Finally, the Ca6La4(SiO4)2(PO4)4O2:Eu2+ phosphor was fabricated with commercial red (CaAlSiN3:Eu2+) and blue (BAM:Eu2+) phosphor coating on a n-UV chip. This proves that this green phosphor has the potential to be used in a w-LED lamp.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia Y., Chen J., Liu Y.-G., Molokeev M. S., Guan M., Huang Z., Fang M.
Заглавие : Crystal structure evolution and luminescence properties of color tunable solid solution phosphors Ca2+xLa8-x(SiO4)6-x(PO4)xO2:Eu2+
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2016. - Vol. 45, Is. 3. - P.1007-1015. - ISSN 14779226 (ISSN), DOI 10.1039/c5dt03786g
Примечания : Cited References: 42. - This work was sponsored by National Natural Science Foundation of China (Grant No. 51472223), the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-12-0951) and the Fundamental Research Funds for the Central Universities (Grant No. 2652015020).
Предметные рубрики: LIGHT-EMITTING-DIODES
WHITE-LIGHT
ENERGY-TRANSFER
SILICATE GLASS
SINGLE-PHASE
EU2+
LEDS
PHOTOLUMINESCENCE
EMISSION
UV
Аннотация: A series of apatite solid solution phosphors Ca2+xLa8-x(SiO4)6-x(PO4)xO2:Eu2+ (x = 0,2,4,6) were synthesized by a conventional higherature solid-state reaction. The phase purity was examined using XRD, XPS and XRF. The crystal structure information, such as the concentration, cell parameters and occupation rate, was analyzed using a Rietveld refinement, demonstrating that the Eu2+ activated the Ca2La8(SiO4)6O2 and Ca8La2(PO4)6O2 to form continuous solid solution phosphors. Different behaviors of luminescence evolution in response to structural variation were verified among the series of phosphors. Two kinds of Eu2+ ion sites were proved using low temperature PL spectra (8k) and room temperature decay curves. The substitution of large La3+ ions by small Ca2+ ions induced a decreased crystal field splitting of the Eu2+ ions, which caused an increase in emission energy from the 5d excited state to the 4f ground state and a resultant blue-shift from 508 nm to 460 nm. Therefore, with the crystal structure evolution, the emitted color of the series of phosphors could be tuned from green to blue by adjusting the ratio of Ca/La. © 2016 The Royal Society of Chemistry.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia Z., Miao S., Molokeev M. S., Chen M., Liu Q.
Заглавие : Structure and luminescence properties of Eu2+ doped LuxSr2-xSiNxO4-x phosphors evolved from chemical unit cosubstitution
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 6. - P.1336-1344. - ISSN 20507534 (ISSN), DOI 10.1039/c5tc04222d
Примечания : Cited References: 32. - This work was supported by the National Natural Science Foundation of China (Grant No. 51572023 and 51272242), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), the Funds of the State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS (RERU2015022), and Fundamental Research Funds for the Central Universities (FRF-TP-15-003A2).
Предметные рубрики: SOLID-SOLUTION PHOSPHORS
WHITE-LIGHT
PHOTOLUMINESCENCE
SUBSTITUTION
DISCOVERY
TRANSITIONLEDS
EVOLUTION
HOST
LEDS
Аннотация: The design scheme of the chemical unit cosubstitution of [Lu3+-N3-] for [Sr2+-O2-] in Sr2SiO4:Eu2+ has been put into practice to discover the new phosphor systems with tunable luminescence properties, and the structures and photoluminescence tuning of yellow-emitting LuxSr2-xSiNxO4-x:Eu2+ phosphors have been investigated. Crystal structures of LuxSr2-x-ySiNxO4-x:yEu2+ samples were resolved using the Rietveld method, suggesting that the as-prepared Sr2SiO4 belonged to monoclinic symmetry (P21/n) of β-phase Sr2SiO4, while Sr1.97Eu0.03SiO4 and Sr1.965Eu0.03Lu0.005SiO3.995N0.005 belonged to orthorhombic symmetry (Pnma) of α-Sr2SiO4. The emission peaks of LuxSr1.97-xSiNxO4-x:0.03Eu2+ phosphors were red-shifted from 563 to 583 nm upon increasing the [Lu3+-N3-] substitution content from x = 0 to x = 0.005, furthermore, the PL emission peaks of Lu0.005Sr1.965-ySiN0.005O3.995:yEu2+ also showed a red-shift from 583 nm to 595 nm with increasing Eu2+ concentration (y = 0.03, 0.07, 0.10 and 0.15), and their corresponding red-shift mechanism has been discussed. The temperature dependent luminescence results further verified that the introduction of [Lu3+-N3-] for [Sr2+-O2-] in Sr2SiO4:Eu2+ can improve the thermal stability of the photoluminescence, which indicated that the LuxSr2-x-ySiNxO4-x:yEu2+ phosphors have potential applications in white light-emitting diodes (wLEDs). © 2016 The Royal Society of Chemistry.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Liu H., Liao L., Molokeev M. S., Guo Q., Zhang Y., Mei L.
Заглавие : A novel single-phase white light emitting phosphor Ca9La(PO4)5(SiO4)F2:Dy3+: Synthesis, crystal structure and luminescence properties
Место публикации : RSC Adv.: Royal Society of Chemistry, 2016. - Vol. 6, Is. 29. - P.24577-24583. - ISSN 20462069 (ISSN), DOI 10.1039/c5ra23348h
Примечания : Cited References: 33. - We gratefully acknowledge the financial support by the National Natural Science Foundations of China (Grant no. 41172053), the Fundamental Research Funds for the Central Universities (Grant no. 2652013043), and Science and Technology Innovation Fund of the China University of Geosciences (Beijing).
Предметные рубрики: Energy-transfer
Diodes
LEDs
Emission
Ions
Excitation
Ce3+
Eu2+
Ln
Аннотация: A novel single-phase white light emitting phosphor Ca9La(PO4)5(SiO4)F2:Dy3+ was prepared through traditional high-temperature solid state technology. The crystal structures of Ca9La(PO4)5(SiO4)F2 with or without Dy3+ ions were refined by the Rietveld method. The diffuse reflection spectra, excitation spectra, emission spectra, and decay times were characterized to investigate the photoluminescence properties for application in white light-emitting diodes. The results showed that the Ca9La(PO4)5(SiO4)F2:Dy3+ phosphor could efficiently assimilate n-UV light and emit blue (∼485 nm) and yellow light (∼580 nm), originating from the f-f transitions of Dy3+. The critical Dy3+ quenching concentration (QC) was determined to be about 15 mol%, and the corresponding QC mechanism was verified to be the dipole-dipole interaction. Additionally, the emission colors of all samples were located close to the ideal white light region, and the optimal chromaticity coordinates and correlated color temperature (CCT) were determined to be (x = 0.338, y = 0.336) and 5262 K. All the above results indicate that the as-prepared Ca9La(PO4)5(SiO4)F2:Dy3+ phosphor could serve as a promising candidate for white-light n-UV-LEDs. © The Royal Society of Chemistry 2016.
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17.

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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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhou Z., Zhang N., Chen J., Zhou X., Molokeev M. S., Guo C.
Заглавие : The Vis-NIR multicolor emitting phosphor Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ for LED towards plant growth
Место публикации : J. Ind. Eng. Chem. - 2018. - Vol. 65. - P.411-417. - ISSN 1226086X (ISSN), DOI 10.1016/j.jiec.2018.05.014
Примечания : Cited References: 36. - This work was supported by National Natural Science Foundation of China (No. 11704312, 11274251), Research Fund for the Doctoral Program of Higher Education of China (RFDP) (No.20136101110017), Foundation of Key Laboratory of Photoelectric Technology in Shaanxi Province (15JS101).
Ключевые слова (''Своб.индексиров.''): phosphor--plant growth--leds--energy transfer
Аннотация: Photosynthesis process is the basic for plant growth, which needs energy from the light. The pigments of chlorophyll a, b and bacteriochlorophyll are responsible for the absorption of light, in which blue, red and near-infrared (NIR) light directly or indirectly promote the plant growth and enhancement of nurtiments. It is important for plant to support absorbable light, and phosphhor-converted light emitting diodes (pc-LEDs) are low-cost, energy-saving and enviromental friendly devices for plant growth. To develop a phosphor with emission covering the blue, red and NIR, a series of phosphors Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ with blue, red and NIR multi-emitting were prepared. Their emissions not only match well with the absorption spectra of pigments in the plant, but also could be excited by near ultraviolet (n-UV) LED chip. The crystal structure of host Ba4Gd3Na3(PO4)6F2 was refined from the XRD data and three different crystallographic sites occupied by Eu2+ were determined through low temperature photoluminescence spectra. The energy transfer from Eu2+ to Pr3+ ions was also discussed in detail. Results indicated that the multi-emitting Ba4Gd3Na3(PO4)6F2: Eu2+, Pr3+ can serve as a phosphor candidate for plant growth LEDs.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zheng Y., Zhang H., Zhang H., Xia Z., Liu Y., Molokeev M. S., Lei B.
Заглавие : Co-substitution in Ca1−xYxAl12−xMgxO19 phosphors: local structure evolution, photoluminescence tuning and application for plant growth LEDs
Место публикации : J. Mater. Chem. C. - 2018. - Vol. 6, Is. 15. - P.4217-4224. - ISSN 20507534 (ISSN), DOI 10.1039/c8tc00165k
Примечания : Cited References: 47. - The present work was supported by the National Natural Science Foundation of China (Grant No. 21671070), the Project for Construction of High-level University in Guangdong Province, and the Teamwork Projects funded by the Guangdong Natural Science Foundation (Grant No. S2013030012842), and the Guangzhou Science & Technology Projects (No. 201704030086, 201605030005), and the reported study was funded by the RFBR according to the research project 17-52-53031. Special Funds for the Cultivation of Guangdong College Students’ Scientific and Technological Innovation (‘‘Climbing Program’’ Special Funds) were granted for Dr Yinjian Zheng.
Ключевые слова (''Своб.индексиров.''): co substitution--crystal structure transformation--high temperature solid-state reaction--lighting systems--local structure--luminescence measurements--structural refinement--tunable luminescences
Аннотация: Herein, Mn4+-activated Ca1-xYxAl12-xMgxO19 (x = 0-0.50) solid solutions were prepared using a conventional high-temperature solid-state reaction. Crystal structure transformation via chemical co-substitution of Y3+/Mg2+ for Ca2+/Al3+ was investigated in detail. The optical properties of Ca1-xYxAl12-xMgxO19 (x = 0-0.50) have been reported for the first time using a combination of techniques including structural refinement and luminescence measurements. Co-doping of Mg and Y cations within the CaAl12O19 host in a controlled manner resulted in the as-prepared samples with red/far-red ratio-tunable luminescence properties. The emission bands well-matched with the absorption band of phytochrome. Interestingly, enhanced Mn4+ luminescence can be obtained upon the addition of Mg2+ and Y3+. Unexpectedly, the quantum yields exhibit a slight change when x is in the range from 0.05 to 0.40; this indicates that these solid solutions have significant potential as lighting systems for plant growth.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhao, Ming, Liao, Hongxu, Molokeev M. S., Zhou, Yayun, Zhang, Qinyuan, Liu, Quanlin, Xia, Zhiguo
Заглавие : Emerging ultra-narrow-band cyan-emitting phosphor for white LEDs with enhanced color rendition
Место публикации : Light: Sci. Appl. - 2019. - Vol. 8. - Ст.38. - ISSN 2047-7538, DOI 10.1038/s41377-019-0148-8
Примечания : Cited References: 31. - The present work was supported by the National Natural Science Foundations of China (Grant Nos. 51722202, 51572023 and 91622125), Natural Science Foundations of Beijing (2172036), Fundamental Research Funds for the Central Universities (FRF-TP-18-002C1), and the Guangdong Provincial Science & Technology Project (No. 2018A050506004). M.S.M. is grateful for the support from the Russian Foundation for Basic Research (Grant No. 17-52-53031).
Предметные рубрики: LUMINESCENCE PROPERTIES
TEMPERATURE
ROUTE
Аннотация: Phosphor-converted white LEDs rely on combining a blue-emitting InGaN chip with yellow and red-emitting luminescent materials. The discovery of cyan-emitting (470–500 nm) phosphors is a challenge to compensate for the spectral gap and produce full-spectrum white light. Na0.5K0.5Li3SiO4:Eu2+ (NKLSO:Eu2+) phosphor was developed with impressive properties, providing cyan emission at 486 nm with a narrow full width at half maximum (FWHM) of only 20.7 nm, and good thermal stability with an integrated emission loss of only 7% at 150 °C. The ultra-narrow-band cyan emission results from the high-symmetry cation sites, leading to almost ideal cubic coordination for UCr4C4-type compounds. NKLSO:Eu2+ phosphor allows the valley between the blue and yellow emission peaks in the white LED device to be filled, and the color-rendering index can be enhanced from 86 to 95.2, suggesting great applications in full-spectrum white LEDs.
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