共查询到20条相似文献,搜索用时 15 毫秒
1.
Ge Zhu Yuhua Wang Zhipeng Ci Bitao Liu Yurong Shi Shuangyu Xin 《Journal of luminescence》2012,132(2):531-536
A single-phased white-light-emitting phosphor Ca8Mg(SiO4)4Cl2:Ce3+, Tb3+ (CMSC:Ce3+, Tb3+) is synthesized by a high temperature solid-state reaction method, and its photoluminescence properties are investigated. The obtained phosphor exhibits a strong excitation band between 250 and 410 nm, matching well with the dominant emission band of a UV light-emitting-diode (LED) chip. Energy transfer from Ce3+ to Tb3+ ions has been investigated and demonstrated to be a resonant type via a dipole–dipole mechanism. The energy transfer efficiency as well as the critical distance is also estimated. Furthermore, the phosphors can generate light from yellow-green through white and eventually to blue by properly tuning the relative ratio of Ce3+ to Tb3+ ions grounded on the principle of energy transfer. The results show that this phosphor has potential applications as a single-phased phosphor for UV white-light LEDs. 相似文献
2.
Ce3+, Tb3+ codoped amorphous calcium silicate phosphor was prepared by heating (830 °C for 30 min) Ce3+, Tb3+ codoped calcium silicate hydrate phosphor formed by liquid-phase reaction. The excitation peak wavelength of the resulting phosphor was 330 nm and the emission peak wavelengths were at 544 nm, attributed to the 5D4→7F5 transition of Tb3+, and at 430–470 mm, attributed to Ce3+. The intensity ratio of the two peaks could be freely controlled by varying the Tb/Ca atomic ratio of the Ce3+, Tb3+ codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from blue to green. It was clarified that energy transfer exists from Ce3+ to Tb3+. 相似文献
3.
Nanocrystalline Y3Al5O12: Ce3+/Tb3+ (average crystalline size 30 nm) phosphor layers were coated on non-aggregated, monodisperse and spherical SiO2 particles by the sol-gel method, resulting in the formation of core-shell structured SiO2@Y3Al5O12:Ce3+/Tb3+ particles. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, photoluminescence,
cathodoluminescence spectra, as well as lifetimes were utilized to characterize the core-shell structured SiO2@Y3Al5O12:Ce3+/Tb3+ phosphor particles. The obtained core-shell structured phosphors consist of well-dispersed submicron spherical particles
with a narrow size distribution. The thickness of the Y3Al5O12:Ce3+/Tb3+ shells on the SiO2 cores (average size about 500 nm, crystalline size about 30 nm) could be easily tailored by varying the number of deposition
cycles (100 nm for four deposition cycles). Under the excitation of ultraviolet and low-voltage electron beams (1–3 kV), the
core-shell SiO2@Y3Al5O12:Ce3+/Tb3+ particles show strong yellow-green and green emission corresponding to the 5d–4f emission of Ce3+ and 5D4–7F
J
(J = 6, 5, 4, 3) emission of Tb3+, respectively. These phosphors may have potential application in field emission displays. 相似文献
4.
Ce3+ and Tb3+ co-doped Sr2B5O9Cl phosphors with intense green emission were prepared by the conventional high-temperature solid-state reaction technique. A broad band centered at about 315 nm was found in phosphor Sr2B5O9Cl: Ce3+, Tb3+ excitation spectrum, which was attributed to the 4f-5d transition of Ce3+. The typical sharp line emissions ranging from 450 to 650 nm were originated from the 5D4 → 7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions. The photoluminescence (PL) intensity of green emission from Tb3+ was enhanced remarkably by co-doping Ce3+ in the Tb3+ solely doped Sr2B5O9Cl phosphor because of the dipole-dipole mechanism resonant energy transfer from Ce3+ to Tb3+ ions. The energy transfer process was investigated in detail. In light of the energy transfer principles, the optimal composition of phosphor with the maximum green light output was established to be Sr1.64Ce0.08Tb0.1Li0.18B5O9Cl by the appropriate adjustment of dopant concentrations. The PL intensity of Tb3+ in the phosphor was enhanced about 40 times than that of the Tb3+ single doped phosphor under the excitation of their optimal excitation wavelengths. 相似文献
5.
Qian Wang Degang Deng Youjie Hua Lihui Huang Huanping Wang Shilong Zhao Guohua Jia Chenxia Li Shiqing Xu 《Journal of luminescence》2012,132(2):434-438
A novel Ce3+/Eu2+ co-activated LiSr4(BO3)3 phosphor has been synthesized by traditional solid-state reaction. The samples could display varied color emission from blue towards white and ultimately to yellow under the excitation of ultraviolet (UV) light with the appropriate adjustment of the relative proportion of Ce3+/Eu2+. The resonance-type energy transfer mechanism from Ce3+ to Eu2+ in LiSr4(BO3)3:Ce3+, Eu2+ phosphors is dominant by electric dipole–dipole interaction, and the critical distance is calculated to be about 29.14 Å by the spectra overlap method. White light was observed from LiSr4(BO3)3:mCe3+, nEu2+ phosphors with chromaticity coordinates (0.34, 0.30) upon 350 nm excitation. The LiSr4(BO3)3:Ce3+, Eu2+ phosphor has potential applications as an UV radiation-converting phosphor for white light-emitting diodes. 相似文献
6.
Ce3+ activated aluminate based phosphors prepared by combustion synthesis are reported here. The emission of Ce3+ ion is observed around 321–354 nm in the ultraviolet region of the spectrum. The intensity of strong photoluminescence emission peak of Ce3+ ion increases when Mg is added to CaAl12O19 phosphor. The Ce3+ emission in CaAl12O19:Ce,Mg phosphor may be useful for scintillation application. 相似文献
7.
Jiayue Sun Yining Sun Jinli Lai Zhiguo Xia Haiyan Du 《Journal of luminescence》2012,132(11):3048-3052
Ce3+ and Tb3+ co-doped BaAl2B2O7 phosphors were synthesized by the solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The photoluminescent properties of Ce3+ and Tb3+ co-doped BaAl2B2O7 phosphors were investigated by using the photoluminescence emission and excitation spectra. Under the excitation of near ultraviolet (n-UV) light, BaAl2B2O7:Ce3+,Tb3+ phosphors exhibited blue emission corresponding to the f–d transition of Ce3+ ions and green emission bands corresponding to the f–f transition of Tb3+ ions, respectively. Effective energy transfer occurred from Ce3+ to Tb3+ in BaAl2B2O7 host due to the observed spectra overlap between the emission spectrum of Ce3+ ion and the excitation spectrum of Tb3+ ion. The energy transfer efficiency from Ce3+ ion to Tb3+ ion was also calculated to be 71%. Furthermore, the concentration quenching and critical distance of BaAl2B2O7:Ce3+,Tb3+ phosphors were also discussed. The energy transfer from Ce3+ to Tb3+ in BaAl2B2O7 host was demonstrated to be resonant type via a dipole–dipole interaction mechanism with the energy transfer critical distance of 16.13 Å. 相似文献
8.
Photoluminescence properties of Ca9Lu(PO4)7:Ce3+, Mn2+ prepared by conventional solid-state reaction
Chengchun Zhao Xin Yin Yaoming Wang Fuqiang Huang Yin Hang 《Journal of luminescence》2012,132(3):617-621
A new red-emitting phosphor Ca9Lu(PO4)7:Ce3+, Mn2+ has been synthesized by solid-state reaction, and its luminescence properties have been investigated. The broad red emission peaked at 645 nm of Mn2+ is greatly enhanced by the sensitizer Ce3+ due to efficient energy transfer from Ce3+ to Mn2+. The energy transfer was demonstrated to belong to a resonant type via a dipole–quadrupole mechanism. The critical distance for Ce3+→Mn2+ energy transfer was calculated to be 15.04 Å by concentration quenching method. Preliminary results indicate that the phosphor might be a promising red phosphor for UV-based white LEDs. 相似文献
9.
Hong Yu Wenwen Zi Shi Lan Shucai Gan Haifeng Zou Xuechun Xu Guangyan Hong 《Optics & Laser Technology》2012,44(7):2306-2311
Sr3MgSi2O8:Ce3+, Tb3+ phosphor samples were prepared using a solid-state reaction technique, and the photoluminescence properties and energy transfer were investigated. Effective energy transfer occurred in Ce3+/Tb3+ co-doped Sr3MgSi2O8 phosphors. Co-doping of Ce3+ was found to enhance the emission intensity of Tb3+ to a certain extent by transferring energy to Tb3+. The Ce3+/Tb3+ energy transfer was thoroughly investigated through its emission/excitation spectra and photoluminescence decay behavior. The color emitted by Sr3MgSi2O8:Ce3+, Tb3+ phosphors varied from blue to green and can be controlled by altering the concentration ratio of Ce3+ to Tb3+. These results indicate that Sr3MgSi2O8:Ce3+, Tb3+ may be useful as a green-emitting phosphor for ultraviolet whitelight-emitting diodes. 相似文献
10.
Blue and green double emitting phosphor, Ce3+ and Tb3+ co-doped NaSr4(BO3)3, was synthesized in a weak reducing atmosphere by a conventional high temperature solid-state reaction technique. For comparison, Ce3+ or Tb3+ singly doped NaSr4(BO3)3 was also prepared. The emission and excitation spectra of all samples have been investigated. NaSr4(BO3)3:Tb3+ excitation includes a strong absorption at about 240 nm and some weak sharp lines in near-ultraviolet (n-UV) spectral region. The excitation of Ce3+ and Tb3+ co-doped NaSr4(BO3)3 shows a strong broad band absorption in the n-UV region from the contribution of Ce3+, which makes it suitable for excitation by a n-UV LED chip. The emission of NaSr4(BO3)3:Ce3+,Tb3+ consists of a blue emission band from Ce3+ and a green emission from Tb3+ under the excitation of n-UV light. Energy transfer between Ce3+ and Tb3+ is also discussed, and the relative intensity of blue emission and green emission could be tuned by adjusting the concentration of Ce3+ and Tb3+. The phosphor NaSr4(BO3)3:Ce3+,Tb3+ could be considered as a double emission phosphor for n-UV excited white light-emitting diodes. 相似文献
11.
Ce3+ and Dy3+-doped LiAl5O8 were synthesized in the present study. The luminescence properties of Ce3+ and Dy3+, and the energy transfer from Ce3+ to Dy3+ were investigated. The Ce3+ species in LiAl5O8 emit one broad band that peaks at 351 nm under the excitation of ultraviolet light, which is attributed to the 5d–4f transitions of Ce3+. The luminescence of Dy3+ in singly doped LiAl5O8 can not be detected due to its low oscillator strength. However, Dy3+ emit intense blue (477 nm) and yellow (569 nm) light after the introduction of Ce3+. This phenomenon demonstrates that there exists effective energy transfer from Ce3+ to Dy3+, which occurs because the emission spectrum of Ce3+ perfectly overlays the excitation spectrum of Dy3+. The energy transfer from Ce3+ to Dy3+ is performed through dipole–dipole interactions. The experimental results show that LiAl5O8 co-doped with Ce3+ and Dy3+ can be a potential two-band (blue and yellow) phosphor. 相似文献
12.
LiCaBO3 was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Dy3+, Tb3+, Tm3+ and Ce3+, on thermoluminescence (TL) of LiCaBO3 phosphor was discussed. We studied the TL properties and some dosimetric characteristics of Ce3+-activated LiCaBO3 phosphor in detail. The effect of the concentration of Ce3+ on TL was investigated, the result of which showed that the optimum Ce3+ concentration was 1 mol%. The TL kinetic parameters of LiCaBO3:0.01Ce3+ were studied by computer glow curve deconvolution (CGCD) method. The three-dimensional (3D) TL emission spectra were also studied, peaking at 431 and 474 nm due to the characteristic transition of Ce3+. We also studied the linearity, annealing condition, reproducibility, fading and different heating rate of the LiCaBO3:0.01Ce3+ phosphor. 相似文献
13.
Luminescent properties and singlet oxygen production using CeF3:Tb3+-based nanoparticles modified with SiO2 and protoporphyrin IX (PpIX) were studied. CeF3:Tb3+ nanopowder was prepared via sol–gel route, with subsequent surface coating by SiO2 layer and the conjugation with photosensitive PpIX molecules. Radioluminescence spectra suggest an energy transfer from Ce3+ to Tb3+ ions and from Tb3+ to molecules of PpIX photosensitizer. The energy transfer was confirmed by photoluminescence decay curves. Singlet oxygen production was detected using a reaction of 1O2 with 3’-(p-aminophenyl) fluorescein (APF) chemical probe after X-Ray excitation. Qualitative changes in time resolved photoluminescence spectra in the region of 520 nm indicate 1O2 generation. Studied nanocomposites may be good candidates for the application in X-ray induced photodynamic therapy. 相似文献
14.
This letter reports the novel three emission bands based on phosphate host matrix, KBaPO4 doped with Eu2+, Tb3+, and Sm3+ for white light-emitting diodes (LEDs). The phosphors were synthesized by solid-state reaction and thermal stability was elucidated by measuring photoluminescence at higher temperatures. Eu2+-doped KBaPO4 phosphor emits blue luminescence with a peak wavelength at 420 nm under maximum near-ultraviolet excitation of 360 nm. Tb3+-doped KBaPO4 phosphor emits green luminescence with a peak wavelength at 540 nm under maximum near-ultraviolet excitation of 370 nm. Sm3+-doped KBaPO4 phosphor emits orange-red luminescence with a peak wavelength at 594 nm under maximum near-ultraviolet excitation of 400 nm. The thermal stabilities of KBaPO4:Ln (Ln=Eu2+, Tb3+, Sm3+), in comparison to commercially available YAG:Ce3+ phosphor were found to be higher in a wide temperature range of 25-300 °C. 相似文献
15.
Ca<sub>2</sub>BO<sub>3</sub>Cl:Ce<sup>3+</sup>,Tb<sup>3+</sup>:A novel tunable emitting phosphor for white light-emitting diode
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<正>Ca2BO3Cl:Ce3+,Ca2BO3Cl:Tb3+,and Ca2BO3Cl:Ce3+,Tb3+ phosphors are synthesized by a high temperature solid-state reaction.The emission intensity of Ce3+ or Tb3+ in Ca2BO3Cl is influenced by the Ce3+ or Tb3+ doping content,and the optimum concentrations of Ce3+ and Tb3+ are 0.03 mol and 0.05 mol,respectively.The concentration quenching effect of Ce3+ or Tb3+ in Ca2BO3Cl occurs,and the concentration quenching mechanism is d-d interaction for either Ce3+ or Tb3+.The Ca2BO3Cl:Ce3+,Tb3+ can produce colour emission from blue to green by properly tuning the relative ratio between Ce3+ and Tb3+,and the emission intensity of Tb3+ in Ca2BO3Cl can be enhanced by the energy transfer from Ce3+ to Tb3+.The results indicate that Ca2BO3Cl:Ce3+,Tb3+ may be a promising double emission phosphor for UV-based white light emitting diodes. 相似文献
16.
A.S. Gouveia-Neto A.F. da Silva L.A. Bueno E.B. da Costa 《Journal of luminescence》2012,132(2):299-304
Rare-earth doped oxyfluoride 75SiO2:25PbF2 nano-structured phosphors for white-light-emitting diodes were synthesized by thermal treatment of precursor sol–gel derived glasses. Room temperature luminescence features of Eu3+, Sm3+, Tb3+, Eu3+/Tb3+, and Sm3+/Tb3+ ions incorporated into low-phonon-energy PbF2 nanocrystals dispersed in the aluminosilicate glass matrix and excited with UV light emitting diode were investigated. The luminescence spectra exhibited strong emission signals in the red (600, 610, 625, and 646 nm), green (548 and 560 nm), and blue (485 nm) wavelength regions. White-light emission was observed in Sm/Tb and Eu/Tb double-doped activated phosphors employing UV-LED excitation at 395 nm. The dependence of the luminescence emission intensities upon annealing temperature and rare-earth concentration was also examined. The results indicated that there exist optimum annealing temperature and activator ion concentration in order to obtain intense visible emission light with high color rendering index. The study suggests that the nanocomposite phosphor based upon 75SiO2:25PbF2 host herein reported is a promising contender for white-light LED applications. 相似文献
17.
《Current Applied Physics》2020,20(5):696-702
Ca3(PO4)2:1mol%Ce3+/xGd3+ (where x = 0.5, 1.0, 3.0 and 5.0 mol%) phosphors were synthesized by the conventional combustion synthesis method. The X-ray diffraction patterns showed their rhombohedral structure with space group of R3c. The optical properties including reflectance, excitation and emission were investigated. The band gaps of the phosphors were calculated from diffuse reflectance spectra data using the Kubelka–Munk function. The photoluminescence (PL) excitation spectra exhibited the broadband 4f–5d transition of Ce3+ ions centered at ~265 nm. The PL emission properties of the Ca3(PO4)2:Ce3+/Gd3+ phosphors were studied as a function of the Gd3+ ion concentration. The Ca3(PO4)2:Ce3+/Gd3+ phosphor had a wide emission band ranging from 320 to 400 nm, and peaking at 365 nm. This emission is ascribed to the transition from the higher 5d band to 2F7/2, 2F5/2 states of the Ce3+ ion. The 365 nm peak shifted to longer wavelengths with increasing concentration of the Gd3+ ion. The CIE chromaticity diagram of Ca3(PO4)2:Ce3+/Gd3+ phosphor showed tunable emission colour from violet to violet-blue, suggesting that this phosphor can act as a source of violet-blue colour for application in information displays, phototherapy and photoluminescent liquid crystal displays. 相似文献
18.
Kwangwon Park Jaebum Lee Jehong Park Jongsu Kim Patrick Kung Seongsin M. Kim Gawngchul Kim 《Journal of luminescence》2010,130(12):2442-2445
Hexagonal Ba1.20Ca0.8?2x?ySiO4:xCe3+,xLi+,yMn2+ phosphors exhibit two emission bands peaking near 400 and 600 nm from the allowed f–d transition of Ce3+ ions and the forbidden 4T1–6A1 transition of Mn2+ ions, respectively. The strong interaction between Ce3+/Mn2+ ions is investigated in terms of energy transfer, crystal field effect, and microstructure by varying their concentrations. They show a higher quenching temperature of 250 °C than that of a commercially used (Ba,Sr)2SiO4:Eu2+ phosphor (150 °C). Finally, mixtures of these phosphors with green-emissive Ba1.20Ca0.70SiO4:0.10Eu2+ are tested and yielded correlated color temperatures from 3500 to 7000 K, and color rendering indices up to 95%. 相似文献
19.
Synthesis and cathodoluminescent properties of Y2SiO5:Tb3+ phosphors prepared from uniform precursor
Deyong Fan Sen Yang Jieqiong Wang Aqun Zheng Xiaoping Song Demei Yu 《Journal of luminescence》2012,132(5):1122-1125
The luminescent properties of phosphors are sensitive to the size of phosphor particles. The commercial Y2SiO5:Tb3+ phosphors usually show relatively larger particle size (5–10 μm) due to the irregular morphology of rare earth oxide precursor and thus degrade the luminescent properties. In this paper, we report the Y2SiO5:Tb3+ phosphors synthesized from the uniform Tb-doped Y2O3 precursor by a homogeneous precipitation method. Compared with the commercial phosphors, the obtained Y2SiO5:Tb3+ phosphors manifest the uniform morphology with much smaller particles distributing from 0.8 μm to 1.9 μm. Consequently, the cathodoluminescent intensity under low excitation voltage (1–5 kV) was increased, demonstrating a strong green emission with a dominant wavelength of 545 nm. Our results indicate an effective way to develop the high-quality phosphors for field emission display. 相似文献
20.
A Eu3+, Tb3+ codoped amorphous calcium silicate phosphor was prepared by heating a Eu3+, Tb3+ codoped calcium silicate hydrate phosphor formed by liquid-phase reaction for 30 min at 900 °C. The excitation peak wavelength of the resulting phosphor was 379 nm and the emission peak wavelengths were at 542 nm, attributed to the 5D4→7F5 transition of Tb3+, and at 613 mm, attributed to the 5D0→7F1 transition of Eu3+. The intensity ratio of the two peaks could be freely controlled by varying the Eu/Tb atomic ratio of the Eu3+, Tb3+ codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from green to red. It was clarified that electron transfer from Tb3+ to Eu3+ is occurring. 相似文献