共查询到20条相似文献,搜索用时 15 毫秒
1.
We present an efficient way to search a host for ultraviolet (UV) phosphor from UV nonlinear optical (NLO) materials. With the guidance, Na3La2(BO3)3 (NLBO), as a promising NLO material with a broad transparency range and high damage threshold, was adopted as a host material for the first time. The lanthanide ions (Tb3+ and Eu3+)-doped NLBO phosphors have been synthesized by solid-state reaction. Luminescent properties of the Ln-doped (Ln=Tb3+, Eu3+) sodium lanthanum borate were investigated under UV ray excitation. The emission spectrum was employed to probe the local environments of Eu3+ ions in NLBO crystal. For red phosphor, NLBO:Eu, the measured dominating emission peak was at 613 nm, which is attributed to 5D0-7F2 transition of Eu3+. The luminescence indicates that the local symmetry of Eu3+ in NLBO crystal lattice has no inversion center. Optimum Eu3+ concentration of NLBO:Eu3+ under UV excitation with 395 nm wavelength is about 30 mol%. The green phosphor, NLBO:Tb, showed bright green emission at 543 with 252 nm excited light. The measured concentration quenching curve demonstrated that the maximum concentration of Tb3+ in NLBO was about 20%. The luminescence mechanism of Ln-doped NLBO (Tb3+ and Eu3+) was analyzed. The relative high quenching concentration was also discussed. 相似文献
2.
Zuoliang Liu Guochun Zhang Jianxiu Zhang Peizhen Fu 《Journal of solid state chemistry》2010,183(6):1437-1441
Using Na2CO3-H3BO3-NaF as fluxes, transparent RE:Na3La9O3(BO3)8 (abbr. RE:NLBO, RE=Er, Yb) crystals have been grown by the top seed solution growth (TSSG) method. The X-ray powder diffraction analysis shows that the RE:NLBO crystals have the same structure with NLBO. The element contents were determined by molar to be 0.64% Er3+ in Er:NLBO, 2.70% Yb3+ in Yb:NLBO, respectively. The polarized absorption spectra of RE:NLBO have been measured at room temperature and show that both Er:NLBO and Yb:NLBO have a strong absorption bands near 980 nm with wide FWHM (Full Wave at Half Maximum) (21 nm for Er:NLBO and 25 nm for Yb:NLBO). Fluorescence spectra have been recorded. Yb:NLBO has the emission peaks at 985 nm, 1028 nm and 1079 nm and the emission peak of Er:NLBO is at 1536 nm. Spectral parameters have been calculated by the Judd-Ofelt theory for Er:NLBO and the reciprocity method for Yb:NLBO, respectively. The calculated values show that Er:NLBO is a candidate of 1.55 μm laser crystals and Yb:NLBO is a candidate for self-frequency doubling crystal. 相似文献
3.
Liya Zhou Wallace C.H. Choy Jianxin Shi Menglian Gong T.I. Yuk 《Journal of solid state chemistry》2005,178(10):3004-3009
Vacuum ultraviolet (VUV) excitation and photoluminescent (PL) properties of Eu3+ and Tb3+ ion-doped aluminate phosphors, GdCaAl3O7:Eu3+ and GdCaAl3O7:Tb3+ have been investigated. X-ray diffraction (XRD) patterns indicate that the phosphor GdCaAl3O7 forms without impurity phase at 900 °C. Field emission scanning electron microscopy (FE-SEM) images show that the particle size of the phosphor is less than 3 μm. Upon excitation with VUV irradiation, the phosphors show a strong emission at around 619 nm corresponding to the forced electric dipole 5D0→7F2 transition of Eu3+, and at around 545 nm corresponding to the 5D4→7F5 transition of Tb3+. The results reveal that both GdCaAl3O7:RE3+ (RE=Eu, Tb) are potential candidates as red and green phosphors, respectively, for use in plasma display panel (PDP). 相似文献
4.
采用优化的高温固相方法制备了稀土离子Eu3+和Tb3+掺杂的La7O6(BO3)(PO4)2系荧光材料,并对其物相行为、晶体结构、光致发光性能和热稳定性进行了详细研究。结果表明,La7O6(BO3)(PO4)2:Eu3+材料在紫外光激发下能够发射出红光,发射光谱中最强发射峰位于616 nm处,为5D0→7F2特征能级跃迁,Eu3+的最优掺杂浓度为0.08,对应的CIE坐标为(0.610 2,0.382 3);La7O6(BO3)(PO4)2:Tb3+材料在紫外光激发下能够发射出绿光,发射光谱中最强发射峰位于544 nm处,对应Tb3+的5D4→7F5能级跃迁,Tb3+离子的最优掺杂浓度为0.15,对应的CIE坐标为(0.317 7,0.535 2)。此外,对2种材料的变温光谱分析发现Eu3+和Tb3+掺杂的La7O6(BO3)(PO4)2荧光材料均具有良好的热稳定性。 相似文献
5.
采用优化的高温固相方法制备了稀土离子Eu~(3+)和Tb~(3+)掺杂的La_7O_6(BO_3)(PO_4)_2系荧光材料,并对其物相行为、晶体结构、光致发光性能和热稳定性进行了详细研究。结果表明,La_7O_6(BO_3)(PO_4)_2∶Eu~(3+)材料在紫外光激发下能够发射出红光,发射光谱中最强发射峰位于616 nm处,为5D0→7F2特征能级跃迁,Eu~(3+)的最优掺杂浓度为0.08,对应的CIE坐标为(0.610 2,0.382 3);La_7O_6(BO_3)(PO_4)_2∶Tb~(3+)材料在紫外光激发下能够发射出绿光,发射光谱中最强发射峰位于544 nm处,对应Tb~(3+)的5D4→7F5能级跃迁,Tb~(3+)离子的最优掺杂浓度为0.15,对应的CIE坐标为(0.317 7,0.535 2)。此外,对2种材料的变温光谱分析发现Eu~(3+)和Tb~(3+)掺杂的La_7O_6(BO_3)(PO_4)_2荧光材料均具有良好的热稳定性。 相似文献
6.
The complex fluoride LiBaF3 and LiBaF3:M(M=Eu, Ce) is solvothermally synthesized at 180°C and characterized by means of X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis and infrared spectroscopy. In the solvothermal process, the solvents, molar ratios of initial mixtures and reaction temperature play important roles in the formation of products. The excitation and emission spectra of the LiBaF3:M(M=Eu,Ce) have been measured by fluorescence spectrophotometer. In the LiBaF3:Eu emission spectra, there is one sharp line emission located at 360 nm arising from f→f transition of Eu2+ in the host lattice, and typical doublet 5d-4f emission of Ce3+ in LiBaF3 powder is shown. 相似文献
7.
A series of lithium europium double tungsto-molybdate phosphors LiEu(WO4)2−x(MoO4)x (x=0, 0.4, 0.8, 1.2, 1.6, 2.0) have been synthesized by solid-state reactions and their crystal structure, optical and luminescent properties were studied. As the molybdate content increases, the intensity of the 5D0→7F2 emission of Eu3+ activated at wavelength of 396 nm was found to increase and reach a maximum when the relative ratio of Mo/W is 2:0. These changes were found to be accompanied with the changes in the spectral feature, which can be attributed to the crystal field splitting of the 5D0→7F2 transition. As the molybdate content increases the emission intensity of the 615 nm peak also increases. The intense red-emission of the tungstomolybdate phosphors under near-UV excitation suggests them to be potential candidate for white light generation by using near-UV LEDs. In this study the effect of chemical compositions and crystal structure on the photoluminescent properties of LiEu(WO4)2−x(MoO4)x is investigated and discussed. 相似文献
8.
N. Lakshminarasimhan 《Journal of solid state chemistry》2004,177(10):3536-3544
Eu3+ luminescence is studied in apatite-related phosphate BiCa4(PO4)3O. Compositions of the formula Bi1−xEuxCa4(PO4)3O [x=0.05, 0.1, 0.3, 0.5, 0.8 and 1.0] are synthesized and they are isostructural with parent BiCa4(PO4)3O. Room temperature photoluminescence shows the various transitions 5D0→7FJ(=0,1,2) of Eu3+. The emission results of compositions with different Eu3+ content show the difference in site occupancy of Eu3+ in Bi1−xEuxCa4(PO4)3O. The intense 5D0-7F0 line at 574 nm for higher Eu3+ content is attributed to the presence of strongly covalent Eu-O bond that is possible by substituting Bi3+ in the Ca(2) site. This shows the preferential occupancy of Bi3+ in Ca(2) site and this has been attributed to the 6s2 lone pair electrons of Bi3+. This is further confirmed by comparing the emission results with La0.95Eu0.05Ca4(PO4)3O. 相似文献
9.
Monazite-type polyphosphate CaLaP3O10 was synthesized by solid-state reaction at 1000 °C and their photoluminescence of Eu3+ and Tb3+ in CaLaP3O10 under ultraviolet (UV) and vacuum-ultraviolet (VUV) excitation were evaluated for the first time. The emission spectra of CaLaP3O10:Eu3+showed that Eu3+ are in a site with inversion symmetry because the magnetic dipole transition 5D0-7F1 was the strongest both upon 254 and 147 nm excitation. Monitored at 621 nm the excitation spectra consisted of host absorption bands, charge transfer band of Eu-O and the intraconfiguration 4f6 transition of Eu3+. Green phosphor CaLaP3O10:Tb3+exhibited better color purity when excited by 147 nm than that excited by 254 nm. With monitored at 542 nm the host absorption bands of CaLaP3O10:Tb3+ were also observed. Besides the host absorption bands there were strong f-d and weak f-f transitions of Tb3+. 相似文献
10.
Jun Yang Guogang Li Chunxia Li Yong Fan Ziyong Cheng 《Journal of solid state chemistry》2010,183(2):451-3802
Nearly monodisperse, homogeneous and well-defined one-dimensional Tb(1−x)(OH)3:xEu3+ (x=0-3 mol%) nanorods have been prepared through hydrothermal method. The size of the Tb(OH)3:Eu3+ rods could be modulated from nano- to micro-scale by using different amount of ammonia solution. They present highly crystallinity in spite of the moderate reaction temperature. Under ultraviolet excitation into the f→f transition of Tb3+ at 382 nm, Tb(OH)3 samples show the characteristic emission of Tb3+ corresponding to 5D4→7F6, 5, 4, 3 transitions; whereas Tb(OH)3:Eu3+ samples mainly exhibit the characteristic emission of Eu3+ corresponding to 5D0→7F1, 2, 4 transitions due to an efficient energy transfer occurs from Tb3+ to Eu3+. The increase of Eu3+ concentration leads to the increase of the energy transfer efficiency from Tb3+ to Eu3+. The PL colors of Tb(OH)3:xEu3+ phosphors can be easily tuned from green, yellow, orange, to red by changing the doping concentration (x) of Eu3+. 相似文献
11.
Hyunsoo Park 《Journal of solid state chemistry》2004,177(1):159-164
The compound previously reported as Ba2Ti2B2O9 has been reformulated as Ba3Ti3B2O12, or Ba3Ti3O6(BO3)2, a new barium titanium oxoborate. Small single crystals have been recovered from a melt with a composition of BaTiO3:BaTiB2O6 (molar ratio) cooled between 1100°C and 850°C. The crystal structure has been determined by X-ray diffraction: hexagonal system, non-centrosymmetric space group, a=8.7377(11) Å, c=3.9147(8) Å, Z=1, wR(F2)=0.039 for 504 unique reflections. Ba3Ti3O6(BO3)2 is isostructural with K3Ta3O6(BO3)2. Preliminary measurements of nonlinear optical properties on microcrystalline samples show that the second harmonic generation efficiency of Ba3Ti3O6(BO3)2 is equal to 95% of that of LiNbO3. 相似文献
12.
A novel non-centrosymmetric borate, BiCd3(AlO)3(BO3)4, has been prepared by solid state reaction methods below 750 °C. Single-crystal XRD analysis showed that it crystallizes in the hexagonal group P63 with a=10.3919(15) Å, c=5.7215(11) Å, Z=2. In its structure, AlO6 octahedra share edges to form 1D chains that are bridged by BO3 groups through sharing O atoms to form the 3D framework. The 3D framework affords two kinds of channels that are occupied by Bi3+/Cd2+ atoms only or by Bi3+/Cd2+ atoms together with BO3 groups. The IR spectrum further confirmed the presence of BO3 groups. Second-harmonic-generation measurements displayed a response of about 0.5×KDP (KH2PO4). UV-vis diffuse reflectance spectrum showed a band gap of about 3.19 eV. Solid-state fluorescence spectrum exhibited the maximum emission peak at around 390.6 nm. Band structure calculations indicated that it is an indirect semiconductor. 相似文献
13.
Ye Jin Weiping Qin Jisen Zhang Yan Wang Chunyan Cao 《Journal of solid state chemistry》2008,181(4):724-729
Eu3+-doped Gd3PO7 nanospheres with an average diameter of ∼300 nm and a narrow size distribution have been prepared by a facile combustion method and structurally characterized by X-ray diffraction and field emission scanning electron microscopy. The luminescent properties were systemically studied by the measurement of excitation/emission spectra, and emission spectra under different temperatures, as well as by photostability. The strong red-emission intensity peaking at 614 nm originates the 5D0→7F2 transition and is observed under 254-nm irradiation, indicating that Eu3+ ions in Gd3PO7 mainly occupied non-centrosymmetry sites. The CIE1931 XY chromaticity coordinates of Gd3PO7:Eu3+ nanospheres are (x=0.654, y=0.345) in the red area, which is near the National Television Standard Committee standard chromaticity coordinates for red. Thus, Gd3PO7:Eu3+ nanospheres may be potential red-emitting phosphors for PDP and Xe-based mercury-free lamps. 相似文献
14.
Eu3+ photoluminescence is studied in La5Si2BO13 with apatite related structure. La5−xEuxSi2BO13 [x=0.05, 0.1, 0.3, 0.5, 0.7, 1.0, 2.0] compositions are synthesized. The emission results shows that Eu3+ ions occupy two different cationic sites viz., La(1) and La(2). The increase in the intensity of 5D0-7F0 line with increasing Eu3+ content shows the preferential occupancy of Eu3+ in La(2) site due to the existence of short La(2)-O(4) (free oxide ion) bond. The observation of antiferromagnetic interactions in Gd and Dy analogues supports the structural features elucidates from photoluminescence studies. 相似文献
15.
SrZnO2:Eu3+ has been synthesized by solid-state reaction and its photoluminescence in ultraviolet (UV)-vacuum ultraviolet (VUV) range was investigated. The broad bands around 254 nm are assigned to CT band of Eu3+-O2−. With the increasing of Eu3+ concentration, Eu3+ could occupy different sites, which leads to the broadening of CT band. A sharp band is observed in the region of 110-130 nm, which is related to the host absorption. The phosphors emit red luminescence centered at about 616 nm due to Eu3+5D0→7F2 both under 254 and 147 nm, but none of Eu2+ blue emission can be observed. 相似文献
16.
SrF2:Eu3+ nanospheres with homogeneous diameter have been synthesized by a microemulsion-mediated hydrothermal method for the first time, in which quaternary microemulsion of CTAB/water/cyclohexane/n-pentanol was used. The possible reaction mechanism and the luminescent properties of SrF2:Eu3+ nanospheres were also investigated in this paper. The morphology and grain sizes of final products were characterized by field emission scanning electron microscopy and transmission electron microscopy, indicating that most of the products were nanospheres with an average diameter of ∼50 nm. Room-temperature emission spectra, recorded under 394-nm excitation, showed that the transition of 5D0 → 7F1 emission be dominating in SrF2:Eu3+ nanospheres. From the dependence of the luminescence intensity on the concentration of Eu3+ ions, the optimal dopant concentration is 2 mol%. 相似文献
17.
Guofeng Wang Yue Xu Lili Wang Guodong Wei Peifen Zhu Ryongjin Kim 《Journal of fluorine chemistry》2008,129(11):1110-1113
The upconversion luminescent properties of YF3:Yb3+(20%)/Tm3+(1%) nanobundles with different sizes (240-500 nm in length) were studied under 980-nm excitation. Ultraviolet (1I6 → 3F4/3H6 and 1D2 → 3H6), blue (1D2 → 3F4 and 1G4 → 3H6), red (1D2 → 3H4, 1G4 → 3F4, and 3F3 → 3H6), and near infrared (3H4 → 3H6) emissions were observed. The results indicated that the relative intensity of the ultraviolet to the blue as well as the blue to the near infrared increased with decreasing the size of nanobundles. Especially, the position of the dominant red emission peak varied with the size of nanobundles. As the length of nanobundles increased to 500 nm, unusual 3F3 → 3H6 transition was observed, which was theoretically explained considering the decrease of the nonradiative transition rate of 3F3 → 3H4. 相似文献
18.
Yanlin Huang Wanxue Zhao Kiwan Jang Ho Sueb Lee Soung-Soo Yi 《Journal of solid state chemistry》2008,181(9):2161-2164
Eu3+-doped triple phosphate Ca8MgR(PO4)7 (R=La, Gd, Y) was synthesized by the general high-temperature solid-state reaction. Excitation and emission spectra as well as luminescence decay were used to characterize the phosphors. Photoluminescence excitation and emission spectra showed that the phosphor could be efficiently excited by UV-vis light from 260 to 450 nm to give bright red emission assigned to the transition (5D0→7F2) at 612 nm. The richness of the red color has been verified by determining their color coordinates (X, Y) from the CIE standard. 相似文献
19.
N. Lakshminarasimhan 《Journal of solid state chemistry》2005,178(11):3284-3292
New oxysilicates with the general formula ALa3Bi(SiO4)3O and ALa2Bi2(SiO4)3O [ACa, Sr and Ba] are synthesized and characterized. Powder X-ray diffraction of these silicates show that they are isostructural with BiCa4(VO4)3O which has an apatite-related structure. Eu3+ luminescence in the newly synthesized oxysilicates show broad emission lines due to disorder of cations. The relatively high intense magnetic dipole transition 5D0→7F1 points to a more symmetric environment. The photoluminescence results confirm that the compounds have apatite-related crystal structure. 相似文献
20.
This work reports the preparation of system containing RE2+ ions (RE=Sm and Eu)-doped in SrB4O7 matrix by ceramic, Pechini and combustion methods. These compounds were prepared by reduction of RE3+ to RE2+ in air, which exhibit some different features according to the preparation method. Photoluminescent properties of these systems were investigated based on the emission and excitation spectral data. The emission spectra of SrB4O7:Eu2+ system prepared by combustion and Pechini methods are characterized by a broad band assigned to interconfigurational 4f65d→4f7 transition, while SrB4O7:Sm2+ compound exhibit narrow emission bands arising from intraconfigurational-4f6 also shows 4G5/2→6HJ′ transitions ( and ) arising from Sm3+ ion, transitions. SrB4O7:RE system prepared by combustion method presents emission bands from RE3+ ions as intense as that arising from RE2+, suggesting that the preparation route is not efficient for the reduction RE3+→RE2+ process. Emission quantum efficiency and radiative emission rates of Sm2+ ion are determined and discussed. 相似文献