Ln(Ln=Y/Gd)VO4:Er3+/Nd3+的制备及发光性能

采用高温固相法制备了Ln（Ln=Y／Gd）VO4掺Er^3＋或Nd^3＋的近红外发光材料。通过X射线粉末衍射（XRD）和光致发光（PL）对样品进行了表征。结果表明：所得产品结晶良好，属于四方晶系，锆石结构。研究了Er^3＋，Nd^3＋的含量、煅烧时间、煅烧温度等对材料近红外发光性质的影响。在Ln（Ln=Y／Gd）VO4：Er^3＋／Nd^3＋中，存在明显的从VO4^3-向Er^3＋／Nd^3＋的能量传递。两种不同的LnVO4（Ln=Y／Gd）基质对发光性质也有一定的影响。小浓度Bi^3＋的掺人可以明显提高YVO4：Er^3＋／Nd^3＋的近红外发光强度。     

Preparation and up-conversion luminescence of hollow La2O3:Ln (Ln = Yb/Er, Yb/Ho) microspheres

Hollow La(2)O(3):Ln (Ln = Yb/Er, Yb/Ho) microspheres with up-conversion (UC) luminescence properties were successfully synthesized via a facile sacrificial template method by employing carbon spheres as hard templates followed by a subsequent heating process. The structure, morphology, formation process, and fluorescent properties are well investigated by various techniques. The results indicate that the hollow La(2)O(3):Ln microspheres can be well indexed to the hexagonal La(2)O(3) phase. The hollow La(2)O(3):Ln microspheres with uniform diameter of about 270 nm maintain the spherical morphology and good dispersion of the carbon spheres template. The shell of the hollow microspheres consists of numerous nanocrystals with the thickness of approximately 40 nm. Moreover, the possible formation mechanism of evolution from the carbon spheres to the amorphous precursor and to the final hollow La(2)O(3):Ln microspheres has also been proposed. The Yb/Er and Yb/Ho codoped La(2)O(3) hollow spheres exhibit bright up-conversion luminescence with different colors derived from different activators under the 980 nm NIR laser excitation. Furthermore, the doping concentration of the Yb(3+) is optimized under fixed concentration of Er(3+)/Ho(3+). This material may find potential applications in drug delivery, hydrogen and Li ion storage, and luminescent displays based on the uniform hollow structure, dimension, and UC luminescence properties.     

Controllable synthesis and tunable luminescence properties of Y2(WO4)3:Ln3+ (Ln = Eu, Yb/Er, Yb/Tm and Yb/Ho) 3D hierarchical architectures

Yttrium tungstate precursors with novel 3D hierarchical architectures assembled from nanosheet building blocks were successfully synthesized by a hydrothermal method with the assistance of sodium dodecyl benzenesulfonate (SDBS). After calcination, the precursors were easily converted to Y(2)(WO(4))(3) without an obvious change in morphology. The as-prepared precursors and Y(2)(WO(4))(3) were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The results reveal that the morphology and dimensions of the as-prepared precursors can be effectively tuned by altering the amounts of organic SDBS and the reaction time, and the possible formation mechanism was also proposed. Upon ultraviolet (UV) excitation, the emission of Y(2)(WO(4))(3):x mol% Eu(3+) microcrystals can be tuned from white to red, and the doping concentration of Eu(3+) has been optimized. Furthermore, the up-conversion (UC) luminescence properties as well as the emission mechanisms of Y(2)(WO(4))(3):Yb(3+)/Ln(3+) (Ln = Er, Tm, Ho) microcrystals were systematically investigated, which show green (Er(3+), (4)S(3/2), (2)H(11/2)→(4)I(15/2)), blue (Tm(3+), (1)G(4)→(3)H(6)) and yellow (Ho(3+), (5)S(2)→(5)I(8)) luminescence under 980 nm NIR excitation. Moreover, the doping concentration of the Yb(3+) has been optimized under a fixed concentration of Er(3+) for the UC emission of Y(2)(WO(4))(3):Yb(3+)/Er(3+).     

K5LnLi2F10(Ln=La,Gd, Y)的合成和Ce^3^+在其中的发光

在Ar气氛中, 采用高温固相反应法合成了K5LnLi2F10(Ln=La, Ce, Gd, Y)化合物,X射线衍射图表明: 除K5YLi2F10外, 均具有与K5NdLi2F10(KNLF)相同的结构。计算了K5LnLi2F10(Ln=Ln, Ce, Gd)的晶胞参数和晶胞体积, 它们随着La^3^+, Ce^3^+,Gd^3^+的离子半径减小而有规律地减小, 测定了K5CexLn1-xLi2F10化合物的激发光谱和荧光光谱, 发现Ce^3^+的激发波长和发射波长随着La^3^+, Gd^3^+, Y^3^+离子的改变几乎不变, 并对这种现象进行了讨论。     

掺三价铈离子四偏磷酸盐NaLn(PO3)4 (Ln=La, Gd)的真空紫外光谱研究

用高温固相法合成了NaLn（PO3）4：1．0％（原子分数）Ce^3＋（Ln=La,Gd）两种粉末发光材料,在合肥国家同步辐射实验室（NSRL）测得两种样品中Ce^3＋的真空紫外光谱。根据真空紫外光谱图,得到了两种稀土偏磷酸盐中所掺Ce^3＋离子5d轨道的能级分裂图。结合NaLa（PO3）4和NaGd（PO3）4的单晶结构数据,发现随着Ln-O平均键长的减小,Ce^3＋离子5d轨道的晶场劈裂（εcfs）、重心位移（εc）和总的红移（total redshilt,D）均增大。根据配体极化模型,计算了两种化合物中掺杂Ce^3＋离子的有效平均键长（Reff）和光谱极化率（αsp）,发现随着平均键长Rav（Ln—O）变短,Ce^3＋离子的光谱极化率（αsp）也随之减小。     

Magnetism of cyano-bridged hetero-one-dimensional Ln3+-M3+ complexes (Ln3+ = Sm,Gd, Yb; M3+ = FeLS,Co)

The reaction of Ln(NO(3))(3).aq with K(3)[Fe(CN)(6)] or K(3)[Co(CN)(6)] and 2,2'-bipyridine in water led to five one-dimensional complexes: trans-[M(CN)(4)(mu-CN)(2)Ln(H(2)O)(4) (bpy)](n)().XnH(2)O.1.5nbpy (M = Fe(3+) or Co(3+); Ln = Sm(3+), Gd(3+), or Yb(3+); X = 4 or 5). The structures for [Fe(3)(+)-Sm(3+)] (1), [Fe(3)(+)-Gd(3+)] (2), [Fe(3)(+)-Yb(3+)] (3), [Co(3)(+)-Gd(3+)] (4), and [Co(3)(+)-Yb(3+)] (5) have been solved; they crystallize in the triclinic space P1 and are isomorphous. The [Fe(3+)-Sm(3+)] complex is a ferrimagnet, its magnetic studies suggesting the onset of weak ferromagnetic 3-D ordering at 3.5 K. The [Fe(3+)-Gd(3+)] interaction is weakly antiferromagnetic. The isotropic nature of Gd(3+) allowed us to evaluate the exchange interaction (J = 0.77 cm(-)(1)).     

Thermal stability, Judd-Ofelt theory analysis and spectroscopic properties of a new Er3+/Yb3+-codoped germano-tellurite glass

The Er3+/Yb3+-codoped 70TeO2-5Li2O-10B2O3-15GeO2 glass was prepared. The thermal stability, absorption spectra, emission spectra and up-conversion spectra were measured and investigated. The Judd-Ofelt analysis based on absorption spectra was performed in order to determine the Judd-Ofelt intensity parameters Omega(t) (t = 2, 4, 6), spontaneous emission probability, radiative lifetime and branching ratios of several Er3+ transitions. It was found that this studied glass has good thermal stability, broad fluorescence full width at half maximum (FWHM), large stimulated emission cross-section and strong up-conversion emissions at about 532, 546 and 659 nm, corresponding to the 2H(11/2)-->4I(15/2), 4S(3/2)-->4I(15/2) and 4F(9/2)-->4I(15/2) transitions of Er3+, respectively under the excitation at 970 nm. The results suggest that this Er3+/Yb3+-codoped germano-tellurite glass may be a potentially useful material for developing potential amplifiers and up-conversion optical devices.     

Crystal Structures of Ln（NO3）3（Ln=La,Yb）Complexes with 12—crown—4

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Luminescence of Sb3+ in rare earth orthoborates LnBO3 (Ln = Sc,Y, La,Gd, Lu)

The luminescence of several Sb³⁺-activated rare earth orthoborates (LnBO₃Sb³⁺; Ln = Sc, Y, La, Gd, Lu) are reported. In all compositions the Stokes shift of the Sb³⁺ luminescence is rather large, resulting in rather low quenching temperatures (200 K or lower). The Stokes shift appears to be dependent on the coordination number and on the radius of the host lattice cation. This is explained from the assumed tendency of the Sb³⁺ ion to occupy an off-center position which becomes more apparent when the space available for the Sb³⁺ ion increases. The present results are compared with those on LnBO₃Bi³⁺. It appears that the Stokes shift of the Bi³⁺ luminescence is more sensitive to the host lattice and is smaller than the Stokes shift of the Sb³⁺ luminescence. This is explained by the large radius of the Bi³⁺ ion compared to the Sb³⁺ ion. In GdBO₃Sb³⁺ thermally activated energy transfer is observed from Gd³⁺ to Sb³⁺.     

Syntheses,structures, and properties of the bis(cyclopentadienyl) rare-earth imidodiphosphinochalocogenido compounds Cp2Ln[N(QPPh2)2] (Ln = La,Gd, Er,or Yb for Q = Se; Ln = Yb for Q = S)

The compounds Cp2Ln[N(QPPh2)2] (Ln = La (1), Gd (2), Er (3), or Yb (4) for Q = Se, Ln = Yb (5) for Q = S) have been synthesized from the corresponding rare-earth tris(cyclopentadienyl) compound and H[N(QPPh2)2]. The structures of compounds 1, 2, 3, and 5, as determined by X-ray crystallography, consist of a Cp2Ln fragment, coordinated eta 3 through two chalcogen atoms and an N atom of the imidodiphosphinochalcogenido ligand [N(QPPh2)2]-. In compound 4, the Cp2Yb moiety is coordinated eta 2 through the two Se atoms of the [N(SePPh2)2]-ligand. 31P and 77Se (for 1) NMR spectroscopies lend insight into the solution nature of these species. Crystal data: 1, C34H30LaNP2Se2, triclinic, P1, a = 9.7959(10) A, b = 12.4134(13) A, c = 13.9077(14) A, alpha = 88.106(2) degrees, beta = 88.327(2) degrees, gamma = 68.481(2) degrees, V = 1572.2(3) A3, T = 153 K, Z = 2, and R1(F) = 0.0257 for the 5947 reflections with I > .2 sigma(I); 2, C34H30GdNP2Se2, triclinic, P1, a = 9.7130(14) A, b = 12.2659(17) A, c = 13.953(2) A, alpha = 88.062(2) degrees, beta = 87.613(2) degrees, gamma = 69.041(2) degrees, V = 1550.7(4) A3, T = 153 K, Z = 2, and R1(F) = 0.0323 for the 5064 reflections with I > 2 sigma(I); 3, C34H30ErNP2Se2, triclinic, P1, a = 9.704(2) A, b = 12.222(3) A, c = 13.980(4) A, alpha = 88.230(4) degrees, beta = 87.487(4) degees, gamma = 69.107(4) degrees, V = 1547.4(7) A3, T = 153 K, Z = 2, and R1(F) = 0.0278 for the 6377 reflections with I > 2 sigma(I); 4, C34H30NP2Se2Yb.C4H8O, triclinic, P1, a = 12.087(4) A, b = 12.429(4) A, c = 23.990(7) A, alpha = 89.406(5) degrees, beta = 86.368(5) degrees, gamma = 81.664(5) degrees, V = 3558.8(18) A3, T = 153 K, Z = 4, and R1(F) = 0.0321 for the 11,883 reflections with I > 2 sigma(I); and 5, C34H30NP2S2Yb, monoclinic, P21/n, a = 13.8799(18) A, b = 12.6747(16) A, c = 17.180(2) A, beta = 91.102(3) degrees, V = 3021.8(7) A3, T = 153 K, Z = 4, and R1(F) = 0.0218 for the 6698 reflections with I > 2 sigma(I).     

Facile synthesis and multicolor luminescent properties of uniform Lu2O3:Ln (Ln=Eu3+, Tb3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) nanospheres

Multicolor Lu(2)O(3):Ln (Ln=Eu(3+), Tb(3+), Yb(3+)/Er(3+), Yb(3+)/Tm(3+), and Yb(3+)/Ho(3+)) nanocrystals (NCs) with uniform spherical morphology were prepared through a facile urea-assisted homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), Fourier transformed infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), and photoluminescence (PL) spectra as well as kinetic decays were employed to characterize these samples. The XRD results reveal that the as-prepared nanospheres can be well indexed to cubic Lu(2)O(3) phase with high purity. The SEM images show the obtained Lu(2)O(3):Ln samples consist of regular nanospheres with the mean diameter of 95 nm. And the possible formation mechanism is also proposed. Upon ultraviolet (UV) excitation, Lu(2)O(3):Ln (Ln=Eu(3+) and Tb(3+)) NCs exhibit bright red (Eu(3+), (5)D(0)→(7)F(2)), and green (Tb(3+), (5)D(4)→(7)F(5)) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Lu(2)O(3):Ln (Ln=Yb(3+)/Er(3+), Yb(3+)/Tm(3+), and Yb(3+)/Ho(3+)) NCs display the typical up-conversion (UC) emissions of green (Er(3+), (4)S(3/2),(2)H(11/2)→(4)I(15/2)), blue (Tm(3+), (1)G(4)→(3)H(6)) and yellow-green (Ho(3+), (5)F(4), (5)S(2)→(5)I(8)), respectively.     

Syntheses, structures and properties of seven isomorphous 1D Ln3+complexes Ln(BTA)(HCOO)(H2O)3 (H2BTA = bis(tetrazoly)amine, Ln = Pr, Gd, Eu, Tb, Dy, Er, Yb) and two 3D Ln3+ complexes Ln(HCOO)3 (Ln = Pr, Nd)

Seven isomorphous 1D chain Ln3+ complexes Ln(BTA)(HCOO)(H2O)3 (Ln = Pr (1), Gd (2), Eu (3), Tb (4) Dy (5), Er (6) and Yb (7)), and two formate coordinating and bridging 3D Ln3+ complexes Ln(HCOO)3 (Ln = Pr (8) and Nd (9)) have been synthesized and characterized by single crystal X-ray diffraction analysis. Although the Ln3+ ions in 1-7 have different radius, the trivalent lanthanide ions in 1-7 show the same coordinated environment. The well-defined single crystal structures of 8 and 9 are first samples for formate-bridged Ln3+ metallic complexes. The luminescent properties of solid samples of 2-5 at room temperature and the magnetic property of 2 have been also reported and discussed in this paper.     

Ce3+在LnOX(Ln=La,Gd或Y;X=Cl,Br或I)中的发光

以激发光谱和发光光谱研究了Ce³⁺在LnOX中的发光。光谱表明当X相同而Ln不同时,谱图上Ce³⁺峰的位置只有较小的移动;而X不同时Ce³⁺峰的位置有明显和有规律地移动,即按照Cl——Br——I次序往长波方向移动,这个次序与X的电负性减小的次序是一致的。还可以看到Ln=La时与Ln=Gd或Y时有差别,而且Ln=La时stokes位移较大,从离子半径角度对这些进行了讨论。     

Electrospinning synthesis and luminescence properties of one-dimensional La(9.33)(SiO4)6O2: Ln3+ (Ln = Ce, Eu, Tb) microfibers

One-dimensional La(9.33)(SiO(4))(6)O(2): Ln(3+) (Ln = Ce, Eu, Tb) microfibers were fabricated by a simple and cost-effective electrospinning method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) and low voltage cathodoluminescence (CL) as well as kinetic decay were used to characterize the resulting samples. SEM and TEM results indicated that the diameter of the microfibers annealed at 1000 °C for 3 h was 200-245 nm. The microfibers were further composed of fine and closely linked nanoparticles. La(9.33)(SiO(4))(6)O(2): Ln(3+) (Ln = Ce, Eu, Tb) phosphors showed the characteristic emission of Ce(3+) (5d → 4f), Eu(3+) ((5)D(0)→(7)F(J)) and Tb(3+) ((5)D(3,4)→(7)F(J)) under ultraviolet excitation and low-voltage electron beams (3-5 kV) excitation. An energy transfer from Ce(3+) to Tb(3+) was observed in the La(9.33)(SiO(4))(6)O(2): Ce(3+), Tb(3+) phosphor under ultraviolet excitation and low-voltage electron beam excitation. Luminescence mechanisms were proposed to explain the observed phenomena. Blue, red and green emission can be realized in La(9.33)(SiO(4))(6)O(2): Ln(3+) (Ln = Ce, Eu, Tb) microfibers by changing the doping ions. So the La(9.33)(SiO(4))(6)O(2): Ln(3+) (Ln = Ce, Eu, Tb) phosphors have potential applications in full-color field emission displays.     

Cation Distribution and Interatomic Interactions in Oxides with Heterovalent Isomorphism: III. Complex Aluminates LnCaAlO4 (Ln = Y,La, Nd,Gd, Ho,Er, Yb)

The heterovalent isomorphism of Ln³+⁺ and Ca^{2 +} cations in stoichiometric LnCaAlO₄ oxides was studied. The X-ray diffractometry of the intensity of Laue background modulations revealed a positive short-range order in Ln^{3 +} and Ca^{2 +} distribution over points of one structural site common for both ions, which results in formation of stable Ln³⁺-Ca²⁺ couples in adjacent nine-coordinate oxygen polyhedra. The degree of order and the interchange energy estimated in the quasichemical approximation depend both on the effective cationic charges and on the number of unpaired f electrons of the lanthanide atom.     

LnBaB9O16:Eu3+(Ln=La,Y)的结构与荧光性质

利用电子衍射、X射线衍射和荧光光谱等方法研究了LnBaB₉O₁₆(Ln=La,Y)的结构特性.LnBaB₉O₁₆为单斜晶系,其中LaBaB₉O₁₆的晶胞参数a=1.3660nm,b=0.7882nm,c=1.6253nm,β=106.15°;YBaB₉O₁₆的晶胞参数a=1.3476nm,b=0.7776nm,c=1.6040nm,β=106.38°.荧光光谱研究表明,这两种化合物结构不同,Y³⁺在YBaB₉O₁₆结构中处于中心对称格位,而LaBaB₉O₁₆中La³⁺的格位则无中心对称性.Gd³⁺部分取代LaBaB₉O₁₆:Eu³⁺中的La³⁺可改善Eu³⁺离子的发光性质.LaBaB₉O₁₆:Eu³⁺在真空紫外区的吸收比较弱,这可能与硼氧比较小有关.     

Er^3＋／Yb^3＋：Sr3Y2（BO3）4晶体的光谱和激光性质

采用提拉法生长了双掺Yb3+和Er3+离子浓度分别为18.63%和0.87%(原子分数)的Sr3Y2(BO3)4晶体.利用测量的偏振吸收谱结合Judd-Ofeh理论,拟合得到了该晶体中Er3+离子的偏振和有效J-O参数.测量了Er3+离子4I13/2能级和Yb3+离子2F5/2能级的荧光衰减曲线,并计算了4I13/2能级的荧光量子效率和Yb3+到Er3+的能量传递效率.利用Fuchtbauer-Ladenberg公式计算了Er3+离子4I13/2→4I15/2跃迁的偏振受激发射截面.在平-凹谐振腔中,利用97nm波长光纤耦合准连续半导体激光端面泵浦1.12mm厚的该晶体,当输出镜透过率为1.5%时,获得了最大输出功率为1.3 w和斜率效率为20%的1560 nm附近的激光输出.结果表明,Er3+/Yb3+:Sr3+Y2+(BO3)4晶体是一种优良的1.5～1.6 μm波段激光的增益介质.     

Neue Thiophosphate: Die Verbindungen Li6Ln3(PS4)5 (Ln: Y,Gd, Dy,Yb, Lu) und Ag3Y(PS4)2

New Thiophosphates: The Compounds Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) and Ag₃Y(PS₄)₂ The new thiophosphates Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) were synthesized by heating mixtures of Ln, P, S, and Li₂S₄ at 900 °C (100 h) and they were investigated by single crystal X‐ray methods. The compounds with Ln = Y (a = 28.390(2), b = 10.068(1), c = 33.715(2) Å, β = 113.85(1)°), Gd (a = 28.327(2), b = 10.074(1), c = 33.822(2) Å, β = 114.297(7)°), Dy (a = 28.124(6), b = 10.003(2), c = 33.486(7) Å, β = 113.89(3)°), Yb (a = 28.178(3), b = 9.977(1), c = 33.392(4) Å, β = 113.65(1)°), and Lu (a = 28.169(6), b = 10.002(2), c = 33.432(7) Å, β = 113.54(3)°) are isotypic and crystallize in a new structure type (C2/c; Z = 12). Main feature are PS₄ tetrahedra isolated from each other surrounding the Ln and Li atoms via their S atoms. The coordination number of the five crystallographically independent Ln atoms is eight, but the polyhedra are quite different and they are interlinked to larger units extending in [010]. The environment of the Li atoms is irregular and formed by five to six S atoms. The crystal structure is compared with that of Li₉Ln₂(PS₄)₅ (Ln: Nd, Gd). For the synthesis of Ag₃Y(PS₄)₂ (a = 16.874(3), b = 9.190(2), c = 9.312(2) Å, β = 123.17(3)°) a mixture of Y, P, S, and Ag₂S was heated to 700 °C (50 h). The thiophosphate crystallizes in a new structure type (C2/c; Z = 4) composed of isolated PS₄ tetrahedra. The two crystallographically independent Ag atoms are surrounded by four S atoms in the shape of distorted tetrahedra. The Ag(1)S₄ polyhedra are cornershared to strands running along [001], which are linked together via Ag(2)S₄ tetrahedra. The environment of the Y atoms is composed of eight S atoms each building distorted square antiprisms. These polyhedra are connected with each other via common edges to a strand running along [001].