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Synthesis,structure and optical properties of novel thermally robust Dy^(3+)-doped Ca_(9)Sc(PO_(4))_(7) phosphors for NUV-excited white leds

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Journal of Rare Earths 2021年第3期39卷 277-283,I0002页

作者： Haiyan Wu Huimin Li Lihong Jiang Ran Pang Su Zhang Da Li Guanyu Liu Chengyu Li Jing Feng Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China Engineering Product Development Singapore University of Technology and Design8 Somapah Road487372Singapore

The powder samples of Ca_(9)Sc(PO_(4))_(7):xDy^(^(3+))white emitting phosphors were prepared via a solid state reaction *** Ca_(9)Sc(PO_(4))_(7):Dy^(3+)samples were researched by using the GSAS Rietveld refinement and X-ray diffraction(XRD) methods,and SEM images and elemental maps were *** 350 nm excitatio n,the emission spectra of Ca_(9)Sc(PO_(4))_(7):xDy^(3+)samples have two obvious peaks and one weak peak at 484,572 and660 nm,corresponding to the characteristic electron transitions of(^(4)F_(9/2)→ ^(6)H_(15/2),blue),(^(4)F_(9/2)→ ^(6)H_(13/2),yellow) and(^(4)F_(9/2)→ 6 H11/2,red),*** concentration quenching effect,decay lifetime and thermal quenching of the as-synthesized Ca_(9)Sc(PO_(4))_(7):Dy^(3+)samples were researched *** Ca_(9)Sc(PO_(4))_(7):0.02 Dy^(3+)phosphor possesses a good thermal stability,of which the emission intensity at 423 K can maintain 79% of the initial value(273 K).In addition,through the study of the chro maticity coordinates of the Ca_(9)Sc(PO_(4))_(7):0.02 Dy^(3+)phosphor,it is found that it is located in the white region,and the Commission Internationalede L’Eclairage(CIE) chromaticity coordinates are(0.339,0.389),The above results show that Ca_(9)Sc(PO_(4))_(7):xDy^(3+)phosphors can be excellent candidate material for applications in NUV-excited white leds.

关键词： Ca_(9)Sc(PO_(4))7:Dy^(3+) white leds Phosphate Photoluminescence Rare earths

Tunable Emission and Energy Transfer of the Novel KY_(1-x)(MoO_(4))_(2-y)(WO_(4))y:xLn^(3+)(Ln^(3+)=Dy^(3+),Eu^(3+),and Tm^(3+))Single-phase white Luminescence Phosphor for white leds

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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1278-1286页

作者： ZHU Hai HE Bin HUANG Weigang Department of Oncology The Third People's Hospital of ChengduAfiliated Hospital of Southwest Jiaotong University&The Second Affiliated Hospital of ChengduChongqing Medical UniversityChengdu 610031China Medical Research Center The Third People's Hospital of ChengduAfiliated Hospital of Southwest Jiaotong University&The Second Afiliated Hospital of ChengduChongqing Medical UniversityChengdu 610031China National Engineering Research Center for Biomaterials College of Biomedical MaterialsSichuan UniversityChengdu 610064China College of Materials Science and Engineering Sichuan UniversityChengd 610064China

The phosphors of KY_(1-x)(MoO_(4))_(2-y)(WO_(4))y:xLn^(3+)(Ln^(3+)=Tm^(3+),Dy^(3+),Eu^(3+))were synthesized by using a sol-gel ***,the crystal structure,luminescence properties,energy transfer,and white emission of the prepared materials were *** molar ratio of the anion group on the photoluminescence(PL)emission and excitation intensity were investigated,revealing that the optimum intensity could be obtained by using=3:*** optimal Dy^(3+) doping concentration of KY(MoO_(4))1.5(WO4)0.5was *** addition,the color-tunable emissions of Dy^(3+)/Eu^(3+)-codoped KY(MoO_(4))1.5(WO4)0.5phosphors were observed because of the effective energy transfer(ET)from Dy^(3+)to Eu^(3+)***,by doping appropriate concentrations of Tm^(3+),Dy^(3+),and Eu^(3+)and different concentrations of(WO_(4))^(2-),white light emitting phosphors KY_(0.92)(WO_(4))2:0.01Tm^(3+),0.06Dy^(3+),0.01Eu^(3+)with excellent color-rending properties were *** chromaticity coordinate was calculated as(x=0.3238,y=0.3173),closing to the artificial daylight(D65,x=0.313,y=0.329)illuminant,and which indicates the potential application of near ultraviolet white light-emitting diodes(Wleds).

关键词： rare earth phosphors white leds energy transfer sol-gel method

Photoluminescent properties of tunable green-emitting oxynitride （Baa-xSrx）Si6012N2 ：Eu2＋ phosphor and its application in white leds

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Journal of Rare Earths 2013年第10期31卷 944-949页

作者： Guantong CHEN Weidong ZHUANG Ronghui LIU Yuanhong LIU Yunsheng HU Huaqiang HE National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced Materials Co. Ltd. Beijing 100088 China

Green emitting Eu2＋-doped （Ba3_xSrx）Si6012N2 solid solutions were synthesized through solid state reaction at 1350 ℃ for 10 h under a N2/H2 atmosphere. The XRD patterns revealed that the solid solution series of （Ba3 x-ySrx）Si6Ol2N2：yEu2＋ with x value ranging from 0-0.6 were established. An efficient and intense tunable green light was observed by varying the cation Sr/Ba ratio. The emission spectra exhibited an entire shift towards long wavelength with increasing ofx value, which was caused by large crystal field splitting and Stokes shift. The x value dependence of emission intensity was discovered and explained by the enhanced probability of electron from excited 4f state to 5d ground state via nonradioactive transition. Highly thermal stability and feasible color coordinates were verified. white leds with excellent photochromic properties were fabricated by packing GaN based blue chips and （Ba Sr）3Si6012N2：Eu2＋ phosphors. All results indicated that the （Ba3_xSrx）SirO12N2：Eu2＋ phosphors were confirmed to be a promising candidate for pc-white leds in solid state lighting.

关键词： oxynitride phosphor solid solution white leds rare earths

Emission-tunable Ba_(2)Y_(1-x)Sc_(x)NbO_(6):Bi^(3+)(0≤x≤1.0)phosphors for white leds

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Journal of Rare Earths 2022年第12期40卷 1819-1826,I0001页

作者： Zhihua Gao Fengyan Fu Lili Niu Min Jin Xiaohong Wang Department of Applied Chemistry Hengshui UniversityHengshui 053000China Sichuan University Chengdu 610041China

Here,we report a series of Bi^(3+)-doped Ba_(2)Y_(1-x)Sc_(x)NbO_(6)(0≤x≤1.0 mol)phosphors by using the traditional high temperature solid-state *** achieve the structural and photoluminescent(PL)information,several experimental characterizations and theoretical calculations were carried out,including X-ray diffraction(XRD),Rietveld refinement,UV-visible diffuse reflectance and PL spectra,temperature dependent PL spectra,and density functional theo retical(DFT)*** XRD results show that the Bi^(3+)-doped Ba_(2)Y_(1-x)Sc_(x)NbO_(6)samples belong to the double-perovskite phase with a cubic space group of Fm3 m,and the diffraction positions shift toward high diffraction angle when the larger Y^(3+)ions are gradually replaced by the smaller Sc^(3+)*** addition,the refined XRD findings show that the Bi^(3+)ions tend to substitute the Y^(3+)and Sc^(3+)sites in the Bi^(3+)-doped Ba_(2)Y_(1-x)Sc_(x)NbO_(6)0white LED device,with the color temperature(CT)of 3678 K,color rendering index(CRI)of 67.9,and CIE coordinates at(0.371,0.376),is achieved.

关键词： Bi^(3+) Double-perovskite Tunable emission Energy transfer white leds Rare earths

Luminescence characteristics of Eu^(2+) activated Ca_2SiO_4,Sr_2SiO_4 and Ba_2SiO_4 phosphors for white leds

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Chinese Physics B 2009年第5期18卷 2068-2071页

作者：王志军杨志平郭庆林李盼来傅广生 College of Physics Science & Technology Hebei University

This paper investigates the luminescence characteristics of Eu2＋ activated Ca2SiO4, Sr2SiO4 and Ba2SiO4 phosphors. Two emission bands are assigned to the f-d transitions of Eu2＋ ions doped into two different cation sites in host lattices, and show different emission colour variation caused by substituting M2＋ cations for smaller cations. This behaviour is discussed in terms of two competing factors of the crystal field strength and covalence. These phosphors with maximum excitation of around 370 nm can be applied as a colour-tunable phosphor for light-emitting diodes （leds） based on ultraviolet chip/phosphor technology.

关键词： luminescence white leds Eu2+ silicate

Synthesis and photoluminescence properties of a red emitting phosphor NaSr_2(NbO_3)_5:RE^(3+)(RE=Sm,Pr) for white leds

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Journal of Rare Earths 2013年第11期31卷 1049-1052页

作者：朱革慈志鹏史玉茸王育华 Department of Materials Science School of Physical Science and Technology Lanzhou University

Rare earth Sm3＋, Pr3＋doped NaSr2（NbO3）5 red phosphors were successfully synthesized. X-ray diffraction analysis indi-cated that all the samples were single phased. The luminescence property was investigated in detail by diffuse-reflectance spectra and photoluminescence spectra measurement. Both NaSr2（NbO3）5：Sm3＋and NaSr2（NbO3）5：Pr3＋phosphors showed strong absorption in near ultraviolet region, which was suitable for application in leds. When excited by UV light, they both emitted bright red emission with CIE chromaticity coordinates （0.603, 0.397） and （0.669, 0.330）, respectively. The optimal doping concentration of Sm3＋doped NaSr2（NbO3）5 was measured to be 0.04 and that for Pr3＋doped NaSr2（NbO3）5 was 0.01. The integral emission intensity was also measured and compared with the commercial red phosphor Y2O3：Eu3＋. The results indicated that NaSr2（NbO3）5：RE3＋（RE=Sm, Pr） have potential to serve as a red phosphor for UV pumped white leds.

关键词： NaSr2(NbO3)5 red phosphor white leds rare earths

Facile Synthesis of BCNO Yellow-Emitting Phosphors Applications for white leds by Microwave Heating

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Acta Metallurgica Sinica(English Letters) 2017年第2期30卷 113-119页

作者： Yan-Fang Yang Jing-Jing Chen Zhi-Yong Mao Guang-Hao Li Jiao Xu Da-Jian Wang Bradley D.Fahlman Tianjin Key Laboratory for Photoelectric Materials and Devices School of Materials Science and EngineeringTianjin University of Technology Department of Chemistry and Biochemistry Science of Advanced Materials ProgramCentral Michigan University

Yellow-emitting BCNO phosphors,applied for white light-emitting-diodes（leds）,were synthesized by a facile microwave heating route at lower temperature within short *** prepared BCNO phosphors exhibited amorphous form and tunable yellow emission in the range of 510–550 nm under the excitation of 450-nm blue *** effects of carbon content on the photoluminescence properties for these BCNO phosphors and their application performances in white leds were investigated in *** demonstrated microwave synthesis route is promising in preparing low-cost phosphors,and the prepared BCNO phosphor may find potential application in blue-based white leds.

关键词： BCNO phosphors Photoluminescence Microwave heating white leds

Luminescence characteristics of LiCaBO_3:Tb^(3+) phosphor for white leds

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Journal of Rare Earths 2010年第1期28卷 30-33页

作者：王志军杨志平李盼来郭庆林杨艳民 College of Physics Science & Technology Hebei University

A novel green phosphor,LiCaBO3:Tb3+,was synthesized by solid state reaction method,its luminescence characteristics were investigated,and the formation of phosphors were confirmed by X-ray powder diffraction(XRD).Its excitation band extended from 220 to 400 nm,which was coupled well with the emission of UV LED(350-410 nm).It exhibited a strong green emission located at 544 nm with chromatic coordination(0.25,0.58).The emission intensities of LiCaBO3:Tb3+ phosphor were influenced by varying Tb3+ concentratio...

关键词： luminescence white leds LiCaBO3:Tb3+ rare earths

Luminous efficacy and color rendering index of high power white leds packaged by using red phosphor

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Journal of Semiconductors 2011年第1期32卷 69-71页

作者：卢鹏志杨华王国宏 Institute of Semiconductors Chinese Academy of Sciences

We packaged a series of high power white leds by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio, respectively, and discussed the excitation and emission spectrum of yellow phosphor and red phosphor and the characteristics of the leds. We found that the luminous efficacy of the white leds covered with the two phosphors mixed by appropriate mass ratio was lower than that of the white leds covered with yellow phosphor, but the color rendering index was improved observably.

关键词： white leds yellow phosphor red phosphor color rendering index luminous efficacy excitation spectrum