共查询到20条相似文献,搜索用时 46 毫秒
1.
Firasat Hussain Stefan Sandriesser Greta R. Patzke 《Journal of solid state chemistry》2011,184(1):214-219
A series of head-on complexes of lanthanoid containing germanotungstates was isolated from a one pot reaction in an acetate buffer at pH 4.5. This convenient approach brought forward the [{Ln(CH3COO)GeW11O39(H2O)}2]12− (Ln=EuIII, GdIII, TbIII, DyIII, HoIII, ErIII, TmIII, and YbIII) family with acetate chelators in the rarely observed μ2: η2-η1 mode. All compounds were structurally characterized using various solid state analytics, such as single crystal X-ray diffraction, FT-IR spectroscopy, and thermogravimetric analysis. The isostructural polyanions crystallize in the monoclinic system (S.G. P21/c). Temperature-dependent magnetic susceptibility measurements were performed on the GdIII-complex which exhibits near perfect Curie-type behavior. 相似文献
2.
The luminescent nanocrystalline Yb3+ and Er3+ codoped KLa(WO4)2 has been prepared by Pechini method. X-ray diffraction and transmission electron microscope were used to study the structure of the obtained samples. The average grain size of these samples depended on the annealing temperature, increasing with the increase of the temperature. The cell parameters and the crystallite size of KYbxEr0.02La0.98−x(WO4)2 nanocrystalline decreased with the increase of x value. Luminescence studies showed that the intensity of upconversion emission of the Yb3+ and Er3+ codoped samples was much stronger than that of the Er3+ single doped samples (pumped by 980 nm LD). The upconversion emission mechanisms suggested that all the three bands of upconversion emissions were two-photon process. 相似文献
3.
J. del-Castillo A. C. Yanes J. Méndez-Ramos V. K. Tikhomirov V. V. Moshchalkov V. D. Rodríguez 《Journal of Sol-Gel Science and Technology》2010,53(3):509-514
89.5(SiO2)10(PbF2)0.5(REF3) silicate glasses have been prepared using room temperature sol–gel processing of Si(OCH2CH3)4, Pb(CH3COO)2·3H2O, RE(CH3COO)3·nH2O and trifluoroacetic acid as a fluorinating agent, where RE stands for rare-earth ions, such as Yb3+, Er3+, Ho3+, Tm3+, or combinations of those ions. On heat treatment of these glasses at about 300–400 °C, the rare-earth doped spherical PbF2 nanocrystals precipitate within SiO2 glass matrix providing transparent nano-structured glass–ceramics, while the diameter of the nanocrystals can be set in the range from 5 to 25 nm by varying time and temperature of the heat
treatment. The structural and photoluminescence studies confirm the incorporation of rare-earth ions into the PbF2 nanocrystals and white and tuneable colour up-conversion luminescence has been detected in case of Yb3+-Er3+-Tm3+ and Yb3+-Ho3+-Tm3+ co-doped nanocrystals by varying dopant ratio and pump power. 相似文献
4.
Kan Zhu Zhengwen Yang Dong Yan Zhiguo Song Dacheng Zhou Rongfei Wang Jianbei Qiu 《Journal of Sol-Gel Science and Technology》2012,62(2):149-152
Tb3+–Yb3+ co-doped Ca5(PO4)3F inverse opal photonic crystals were prepared by a self-assembly technique in combination with a sol–gel method. Upconversion
luminescence characteristics of the inverse opals were investigated. The results indicate that photonic band gap has a significant
effect on upconversion luminescence of Tb3+–Yb3+ co-doped Ca5(PO4)3F inverse opal. Significant inhibition of the green or blue upconversion luminescence was inspected if the photonic band gap
overlapped with the emission band of Tb3+ ions. 相似文献
5.
H. Wang 《Journal of solid state chemistry》2009,182(10):2716-171
Spherical SiO2 particles have been coated with rare earth oxide layers by a Pechini sol-gel process, leading to the formation of core-shell structured SiO2@RE2O3 (RE=rare earth elements) and SiO2@Gd2O3:Ln3+ (Ln=Eu, Tb, Dy, Sm, Er, Ho) particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence spectra as well as lifetimes were used to characterize the resulting SiO2@RE2O3 (RE=rare earth elements) and SiO2@Gd2O3:Ln3+ (Eu3+, Tb3+, Dy3+, Sm3+, Er3+, Ho3+) samples. The obtained core-shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 380 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (40 nm for two deposition cycles). Under the excitation of ultraviolet, the Ln3+ ion mainly shows its characteristic emissions in the core-shell particles from Gd2O3:Ln3+ (Eu3+, Tb3+, Sm3+, Dy3+, Er3+, Ho3+) shells. 相似文献
6.
To develop new emission-tunable upconversion (UC) phosphors, the Sr3AlO4F:5%Yb3+, xEr3+, yHo3+ (0 ≤ x ≤ 1%, 0 ≤ y ≤ 1%) samples were prepared by conversional solid-state reaction method, and their luminescence properties upon 980 nm excitation were studied. Upon 980 nm excitation, Yb3+-Er3+ codoped Sr3AlO4F shows a predominant emission peak between 645 and 700 nm which is attributed to the 4F9/2-4I15/2 transition of Er3+, and the Er3+ green emissions have been almost quenched. In this case, the yellowish green emitting light is obtained. The possible reason was interpreted by the energy level diagram and the proposed UC mechanism. For Yb3+-Ho3+ codoped Sr3AlO4F, three emissions are observed obviously which are all derived from the Ho3+ ion. The corresponding chromaticity coordinates indicate a red emission has been gained. To realize the tunable emission, the typical Sr3AlO4F:5%Yb3+, 0.2%Er3+, 1%Ho3+ phosphor was developed, and its emission spectrum includes the emission peaks of both Er3+ and Ho3+. Correspondingly, the sample gives a yellow emission. 相似文献
7.
采用水热法制备出Ca9Y(PO4)7:Ce3+,Tb3+纳米荧光粉,通过XRD、SEM和荧光光谱等对样品进行了分析,研究在Ca9Y(PO4)7基质中引入Ce3+,Tb3+离子对发光性能的影响规律。研究发现因Tb3+离子自身能量交叉驰豫的存在,使得单掺Tb3+时,通过调节Tb3+离子的浓度可以实现对发光颜色的控制。同时研究了Ce3+-Tb3+之间的能量传递为电多极相互作用的偶极-四极机制,Ce3+-Tb3+之间最大的能量传递效率为55.6%。Ca9Y(PO4)7:Ce3+,Tb3+的发光颜色可以通过激活离子之间的能量传递和共发射得到可控调节。SEM分析表明荧光粉颗粒尺寸在100 nm左右,分散性好。 相似文献
8.
Karolina Kazmierczak 《Journal of solid state chemistry》2011,184(5):1221-1226
The lanthanide sulphate octahydrates Ln2(SO4)3·8H2O (Ln=Ho, Tm) and the respective tetrahydrate Pr2(SO4)3·4H2O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln2(SO4)3·8H2O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, aHo=13.4421(4) Å, bHo=6.6745(2) Å, cHo=18.1642(5) Å, βHo=102.006(1) Å3 and aTm=13.4118(14) Å, bTm=6.6402(6) Å, cTm=18.1040(16) Å, βTm=101.980(8) Å3), Pr2(SO4)3·4H2O adopts space group P21/n (a=13.051(3) Å, b=7.2047(14) Å, c=13.316(3) Å, β=92.55(3) Å3). The vibrational and optical spectra of Ho2(SO4)3·8H2O and Pr2(SO4)3·4H2O are also reported. 相似文献
9.
Yao Xie Guotao Sun Gabrielle A. Mandl Steven L. Maurizio Jiabo Chen Prof. John A. Capobianco Prof. Lining Sun 《Angewandte Chemie (International ed. in English)》2023,62(4):e202216269
Lanthanide-doped metal–organic frameworks (Ln-MOFs) have versatile luminescence properties, however it is challenging to achieve lanthanide-based upconversion luminescence in these materials. Here, 1,3,5-benzenetricarboxylic acid (BTC) and trivalent Yb3+ ions were used to generate crystalline Yb-BTC MOF 1D-microrods with upconversion luminescence under near infrared excitation via cooperative luminescence. Subsequently, the Yb-BTC MOFs were doped with a variety of different lanthanides to evaluate the potential for Yb3+-based upconversion and energy transfer. Yb-BTC MOFs doped with Er3+, Ho3+, Tb3+, and Eu3+ ions exhibit both the cooperative luminescence from Yb3+ and the characteristic emission bands of these ions under 980 nm irradiation. In contrast, only the 497 nm upconversion emission band from Yb3+ is observed in the MOFs doped with Tm3+, Pr3+, Sm3+, and Dy3+. The effects of different dopants on the efficiency of cooperative luminescence were established and will provide guidance for the exploitation of Ln-MOFs exhibiting upconversion. 相似文献
10.
The new oxyborate phosphors, Na3La9O3(BO3)8:Eu3+ (NLBO:Eu) and Na3La9O3(BO3)8:Tb3+ (NLBO:Tb) were prepared by solid-state reactions. The photoluminescence characteristics under UV excitation were investigated. The dominated emission of Eu3+ corresponding to the electric dipole transition 5D0→7F2 is located at 613 nm and bright green luminescence of NLBO:Tb attributed to the transition 5D4→7F5 is centered at 544 nm. The concentration dependence of the emission intensity showed that the optimum doping concentration of Eu and Tb is 30% and 10%, respectively. 相似文献
11.
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
12.
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
13.
Dr. Qiushui Chen Prof. Xiaoji Xie Prof. Bolong Huang Liangliang Liang Dr. Sanyang Han Zhigao Yi Dr. Yu Wang Prof. Ying Li Prof. Dianyuan Fan Prof. Ling Huang Prof. Xiaogang Liu 《Angewandte Chemie (International ed. in English)》2017,56(26):7605-7609
A new class of lanthanide-doped upconversion nanoparticles are presented that are without Yb3+ or Nd3+ sensitizers in the host lattice. In erbium-enriched core–shell NaErF4:Tm (0.5 mol %)@NaYF4 nanoparticles, a high degree of energy migration between Er3+ ions occurs to suppress the effect of concentration quenching upon surface coating. Unlike the conventional Yb3+-Er3+ system, the Er3+ ion can serve as both the sensitizer and activator to enable an effective upconversion process. Importantly, an appropriate doping of Tm3+ has been demonstrated to further enhance upconversion luminescence through energy trapping. This endows the resultant nanoparticles with bright red (about 700-fold enhancement) and near-infrared luminescence that is achievable under multiple excitation wavelengths. This is a fundamental new pathway to mitigate the concentration quenching effect, thus offering a convenient method for red-emitting upconversion nanoprobes for biological applications. 相似文献
14.
Novel rare earth ions-doped oxyfluoride nano-composite with efficient upconversion white-light emission 总被引:1,自引:0,他引:1
Daqin Chen Yunlong Yu Ping Huang Fangyi Weng 《Journal of solid state chemistry》2008,181(10):2763-2767
Transparent SiO2-Al2O3-NaF-YF3 bulk nano-composites triply doped with Ho3+, Tm3+ and Yb3+ were fabricated by melt-quenching and subsequent heating. X-ray diffraction and transmission electron microscopy measurements demonstrated the homogeneous precipitation of the β-YF3 crystals with mean size of 20 nm among the glass matrix, and rare earth ions were found to partition into these nano-crystals. Under single 976 nm laser excitation, intense red, green and blue upconversion emissions were simultaneously observed owing to the successive energy transfer from Yb3+ to Ho3+ or Tm3+. Various colors of luminescence, including bright perfect white light, can be easily tuned by adjusting the concentrations of the rare earth ions in the material. The overall energy efficiency of the white-light upconversion was estimated to be about 0.2%. 相似文献
15.
The structural and optical properties of the Er3+-Tm3+-Yb3+codoped CaMoO4 phosphors prepared by chemical route have been explored. The crystalline structures of the prepared phosphors have been investigated with the help of X-ray diffraction analysis. The presence of different vibrational modes and absorption bands arising due to the transitions from the ground state to different excited states of rare earth ions have been identified using the Raman and UV-VIS-NIR absorption spectra of the developed phosphor, respectively. The concentration quenching effect on the luminescence property of the prepared materials has been explained in detail. The upconversion luminescence property of the Er3+-Tm3+-Yb3+codoped CaMoO4 phosphor annealed at different temperatures under 980 nm and 808 nm excitations have been reported. The energy transfer Er3+ → Tm3+, Yb3+ → Er3+ and Tm3+ has been found to be responsible for efficient UC emission. The dipole-dipole interaction is observed to be responsible for the concentration quenching of the luminescence intensity. The effect of annealing temperature on the upconversion luminescence property has been explained in detail. The results suggest that the developed tri-doped phosphor may be suitable in making the efficient NIR to visible upconverter and lighting based optical devices. 相似文献
16.
Anna Dobrowolska 《Journal of solid state chemistry》2011,184(7):1707-1714
Powders of calcium yttrium silicate, Ca3Y2(Si3O9)2, containing 0.1-3% Tb3+ were prepared using a sol-gel method and characterized with XRD, IR, UV-vis and UV-VUV spectroscopies at room temperature and 10 K. Structural analysis revealed pure monoclinic phase of Ca3Y2(Si3O9)2 after heat-treatment at 1000 °C. Infrared spectroscopy showed that between 800 and 900 °C a short-range structural organization of the components proceeded, yet without crystallization. A strong emission of Tb3+ had been observed both in the green part of the spectrum due to the 5D4→7FJ transitions and in the blue-violet region owing to the 5D3→7FJ radiative relaxation. The color of the light could be tuned from yellowish-green to bluish-white both by means of the dopant content and the temperature of synthesis. Efficient luminescence of Tb3+-doped Ca3Y2(Si3O9)2 phosphors could also be obtained upon stimulation with vacuum ultraviolet synchrotron radiation demonstrating that an energy transfer from the host to the Tb3+ ions takes place. 相似文献
17.
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
18.
Chu-Chi Ting Yi-Shan Chiu Chia-Wei Chang Liang-Chih Chuang 《Journal of solid state chemistry》2011,184(3):563-9
Er3+-doped Y2Ti2O7 nanocrystals were fabricated by the sol-gel method. While the annealing temperature exceeds 757 °C, amorphous pyrochlore phase ErxY2−xTi2O7 transfers to well-crystallized nanocrystals, and the average crystal size increases from ∼70 to ∼180 nm under 800-1000 °C/1 h annealing. ErxY2−xTi2O7 nanocrystals absorbing 980 nm photons can produce the upconversion (526, 547, and 660 nm; 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2, respectively) and Stokes (1528 nm; 4I13/2→4I15/2) photoluminescence (PL). The infrared PL decay curve is single-exponential for Er3+ (5 mol%)-doped Y2Ti2O7 nanocrystals but slightly nonexponential for Er3+ (10 mol%)-doped Y2Ti2O7 nanocrystals. For 5 and 10 mol% doping concentrations, the mechanism of up-converted green light is the two-photon excited-state absorption. Much stronger intensity of red light relative to green light was observed for the sample with 10 mol% dopant. This phenomenon can be attributed to the reduced distance between Er3+-Er3+ ions, resulting in the enhancement of the energy-transfer upconversion and cross-relaxation mechanisms. 相似文献
19.
Anatase TiO2 nanobelts doped with rare earth (RE) ions Yb3+, Er3+ or Yb3+/Er3+ have been prepared using layered titanate nanobelts (LTO NBs) with RE ions as the precursor obtained by ion-exchange between LTO NBs and RE ions under hydrothermal process. Various measurement results demonstrate that the RE ions have doped into the lattice of TiO2, and the Er3+ or Yb3+/Er3+ doped nanobelts show strong visible up-conversion (UC) fluorescence under 980 nm excitation. The UC emission intensity of LTO NBs embedded with Er3+ or Yb3+/Er3+ is slightly higher than that of the corresponding TiO2 nanobelts doped with RE ions, whereas higher RE doping content leads to the decrease of UC emission intensity due to the concentration-quenching effect. 相似文献
20.
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