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利用固相法合成了Li + 、Eu 3+ 掺杂的NaY(WO 4 ) 2 红色荧光粉, 并且用X射线粉末衍射仪和紫外-可见光谱仪进行了表征。研究发现纯相产物可以在1100℃下制备, 然而稳定存在的温度区间仅约100℃。和已报道的燃烧法产物不同, Eu 3+ 掺杂产物的发光性质证实了浓度猝灭现象的存在, 掺杂9mol％时发光最强, 有效激发波长是393 nm, 发射光谱体现为高选择性的Eu 3+ 的 5 D 0 → 7 F 2 电偶极跃迁, 因此适合于解决白光LED中缺乏红光成分的问题。Li ＋ 掺杂既没有改变Eu 3+ 红光发射的择优性, 又能够调节发光强度。研究发现合适的Li ＋ 浓度可以增强发光, 但是浓度过大或过小对发光不利, 掺杂30mol％时发光最强。这种变化规律可以归因于点阵缺陷增加和Y原子格位不对称性增强对发光强度的不同影响之间竞争的结果。

In this work, large-scale three-dimensional "flake-ball" microarchitectures of Eu(3+) doped white light hydroxyl sodium yttrium tungstate were prepared by the well-known hydrothermal approach at 180 degrees C for 48 h in the presence of triblock-copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123). NaY(WO(4))(2):Eu(3+) phosphor was formed by annealing the hydrothermal product at approximately 630 degrees C for 2 h. A time-dependent microstructure evolution study was performed under hydrothermal reaction. The evolution process is the self-assembly process of P123, and the effects of other reaction parameters, such as influence of the concentration of P123 on morphology, and the influence of temperature on PL. The mechanism by which the "flake-ball" particles are formed is discussed in detail. The PL spectra of Eu(3+)-doped hydroxyl sodium yttrium tungstate phosphor contain two parts: the broad blue-green band and the (5)D(0)--(7)F(J) (J = 1, and 2) characteristic transition of Eu(3+). This approach provides a facile route for the production of high-quality hydroxyl sodium yttrium tungstate microstructures with an interesting optical property.

The luminescent characteristics of RE (RE3+ = Eu, Tb, Dy, Sm and Tm)-doped K2GdZr(PO4)3 have been investigated. The band in the range of 130–157 nm in the VUV excitation spectra of these compounds is attributed to the host lattice or PO43− group absorption and the band from 157 nm to 215 nm with the maximum at 188 nm is due to the O–Zr charge transfer transition. For Eu3+-doped sample, the relatively weak band of O2−–Eu3+ charge transfer (CTB) at 222 nm is observed and for Tb3+-doped sample, the band at 223 nm is related to the 4f–5d spin-allowed transition of Tb3+. For Dy3+- and Sm3+-doped samples, the O2−–Dy3+ and O2−–Sm3+ CTBs have not been observed, probably due to the 2p electrons of oxygen tightly bound to the zirconium ion in the host lattice. In Tm3+-doped sample, the weak O2−–Tm3+ CTB is located at 170 nm. It is observed that there is energy transfer between the host and the luminescent activators (e.g. Eu3+, Tb3+ and Sm3+) except for Tm3+.

A new efficient blue phosphor, Eu2+ activated SrZnP2O7, has been synthesized at 1000 °C under reduced atmosphere and the crystal structure and photoluminescence properties have been investigated. The crystal structure of SrZnP2O7 was obtained via Rietveld refinement of powder X-ray diffraction (XRD) pattern. It was found that SrZnP2O7 crystallizes in space group of P21/n (no. 14), Z=4, and the unit cell dimensions are: a=5.30906(2) A, b=8.21392(3) A, c=12.73595(5) A, β=90.1573(3)°, and V=555.390(3) A3. Under ultraviolet excitation (200–400 nm), efficient Eu2+ emission peaked at 420 nm was observed, of which the luminescent efficiency at the optimal concentration of Eu2+ (4 mol%) was estimated to be 96% as that of BaMgAl10O17:Eu2+. Hence, the SrZnP2O7:Eu2+ exhibit great potential as a phosphor in different applications, such as ultraviolet light emitting diode and photo-therapy lamps.

Three rare earth borosilicate oxyapatites, RE {sub 5}Si{sub 2}BO{sub 13} (RE=La, Gd, Y), were synthesized via wet chemical method, of which RE {sub 5}Si{sub 2}BO{sub 13} (RE=Gd, Y) were first reported in this work. In the three oxyapatites, [BO{sub 4}] and [SiO{sub 4}] share the [TO{sub 4}] tetrahedral oxyanion site, and RE {sup 3+} ions occupy all metal sites. The differential scanning calorimetry-thermo gravimetry measurements and high temperature powder X-ray diffraction pattern revealed a vitrification process within 300-1200 deg. C, which was due to the glass-forming nature of borosilicates. From the VUV excitation spectra of Eu{sup 3+} and Tb{sup 3+} in RE {sub 5}Si{sub 2}BO{sub 13}, the optical band gaps were found to be 6.31, 6.54 and 6.72 eV for RE {sub 5}Si{sub 2}BO{sub 13} (RE=La, Gd, Y), respectively. The emission and excitation bands of Eu{sup 3+} and Tb{sup 3+} are discussed relating with their coordination environments. Among the three hosts, Y{sub 5}Si{sub 2}BO{sub 13} would be the best for Eu{sup 3+} and Tb{sup 3+}-doped phosphors. - Graphical abstract: The perspective view of RE {sub 5}Si{sub 2}BO{sub 13} (RE=La, Gd, Y) oxyapatite along [001] direction. All non-tetrahedral metal sites are occupied by RE {sup 3+}, and the tetrahedral sites bymore » SiO{sub 4} and BO{sub 4} groups. Y{sub 5}Si{sub 2}BO{sub 13} is a good host for both Eu{sup 3+} and Tb{sup 3+} activated phosphors.« less

Two new anhydrous sodium borophosphates with one-dimensional structure, Na3B6PO13 (1) and Na3BP2O8 (2), were synthesized by low-temperature molten salts techniques using boric acid and sodium dihydrogen phosphate as flux, respectively. The crystal structures were solved by means of single-crystal X-ray diffraction (1, orthorhombic, Pnma (no. 62), a = 9.3727 ( 4 ) A , b = 16.2307 ( 7 ) A , c = 6.7232 ( 3 ) A , Z = 4 ; 2 , monoclinic, C2/c (no. 15), a = 12.567 ( 4 ) A , b = 10.290 ( 3 ) A , c = 10.210 ( 3 ) A , β = 92.492 ( 5 ) ° , Z = 8 ). Compound 1 is characterized by an infinite chain of ∞ 1 { [ B 6 PO 13 ] } 3 - containing eight-membered rings in which all vertexes of borate groups contribute to interconnection. Compound 2 reveals an infinite straight chain ∞ 1 { [ BP 2 O 8 ] } 3 - built of vertex-sharing four-membered rings, and chains in neighboring layers arranged along different orientations. The relations between structures and the synthetic conditions with only traced water are discussed.

Two new lanthanum phosphite hydrates, La2(H2O)(HPO3)3 (1) and La2(H2O)2(HPO3)3 (2), were synthesized by a hydrothermal method. Their crystal structures were determined by X-ray single-crystal method (1, monoclinic, C 2 / c (No. 15); a = 20.820 ( 5 ) A , b = 6.717 ( 2 ) A , c = 14.123 ( 3 ) A , β = 101.261 ( 3 ) ° , V = 1937.0 ( 8 ) A 3 ; Z = 8 ; 2, triclinic, P-1 (No. 2); a = 8.168 ( 3 ) A , b = 8.439 ( 2 ) A , c = 9.337 ( 3 ) A , α = 115.641 ( 3 ) ° , β = 98.655 ( 3 ) ° , γ = 105.124 ( 3 ) ° , V = 533.87 ( 1 ) A 3 , Z = 2 ). Both crystal structures present three-dimensional open-framework structures containing channels, and 1 adopts intersecting type. In the two structures, the face-sharing dimers of LaOn ( n = 8 , 9 ) were observed. Other characterizations by IR and TG–DSC were also described. Furthermore, both the compounds doped with Ce+3 showed intensive broad emission band around 340 nm under UV excitation.

The first lutetium diphosphate NH4LuP2O7 has been prepared by a two-step, low-temperature self-flux synthesis in the presence of the F– anion, functioning as a mineralizer, which played a significant role in the synthetic process. The crystal structure has been characterized by single-crystal X-ray diffraction. The title compound crystallizes in a monoclinic system of the space group P21/c (No. 14), a = 7.651(2) A, b = 10.789(2) A, c = 8.577(2) A, β = 105.75(3)°, V = 681.4(2) A3, Z = 4. The three-dimensional framework of NH4LuP2O7, composed of Lu2P4O14 building units formed by vertex-linking LuO6 and P2O7 goups, is isostructural with compounds of the type KAlP2O7 in the ternary diphosphate(AIMIIIP2O7) system. X-ray-excited luminescence measurements of Ce-activated samples show insteresting scintillation properties with a short decay time of 16 ns at room temperature. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

A new borophosphate NH4Cd(H2O)2(BP2O8)·0.72H2O has been synthesized under mild hydrothermal conditions. The crystal structure was characterized by single crystal X-ray diffraction method. Crystal Data: Hexagonal, P65 (No.176), a = 9.6978(16) A, c = 16.026(4) A, V = 1305.3(4) A3, Z = 6, R1 = 0.0256 and wR2 = 0.0665 for 1409 observed unique reflections and 146 variables. The structure is characterized by corner-sharing PO4 and BO4 tetrahedra, leading to infinite helical {[BP2O8]3−} ribbons, which are connected by CdO4(H2O)2 coordination octahedra. Nevertheless, the structure reveals significant difference from its other ammonium containing analogues with respect to the occupations of NH4+ and the metal cation. The abnormal changes of the unit cells comparing with cadmium borophosphates with other counter cations were presumably due to the anisotropic hydrogen bonds along the c-axis or on the ab-plane. Its UV-Vis fluorescence property was investigated for the first time.

Two transition-metal phosphites, Na2[M(HPO3)2] (M = Fe, Co) with a new structure type have been synthesised under mild hydrothermal conditions and the solid-state structures have been elucidated by single-crystal X-ray diffraction studies. The structures are of a new type with the following data: orthorhombic, Pnma, a = 12.169(4), b = 5.441(2) and c = 9.146(3) A for the iron species 1 and a = 12.091(3), b = 5.400(4) and c = 9.115(2) A for the cobalt compound 2, with Z = 4. The crystal structures of these compounds are isotypic and built up from a 3D open framework with 4-, 6- and 12-membered polyhedral rings of vertex-linked MO6 and HPO3 building units. The inorganic frameworks contains 12-membered ring channel systems in which the sodium ions are located. The topology of this structure type is remarkably similar to that of the aeschynite CaTa2O6 with much larger channels. Magnetic measurements of Na2[Co(HPO3)2] show different magnetic features in the low-temperature (5–30 K) and high-temperature ranges (100–320 K) suggesting the possible existence of a complex magnetic structure. Antiferromagnetic ordering can be observed as a broadened cusp in χ–1 at θ = 2.6 K. For Na2[Fe(HPO3)2], the magnetic behavior follows the Curie–Weiss law with μeff = 5.41 μB, fitted for 100–320 K. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

A new microporous borogermanate NH4[BGe3O8] has been synthesized by a molten boric acid flux method with "reagent" quantities of water in which GeO2, ethylenediamine, H2O, and H3BO3 (5:8:14:25) were heated together at 513 K for 4 days. The structure consists of {Ge6O18}n chains, further linked together via BO4 tetrahedra, forming a three-dimensional open framework with intersecting channel systems including one-dimensional 10-membered-ring (MR) channels. Interestingly, the infinite chains {Ge6O18}n as building blocks, built of alternating 4- and 6-MRs made of vertex-sharing GeO4 tetrahedra, construct the borogermanate framework. It is noteworthy that the high viscosity of the reactive medium and the quantity of water play important roles in the formation of the compound.

A new organically templated cadmium chlorophosphate, (C3H6N2)[Cd2Cl2(HPO4)2] (C3H6N2 = diprotonated imidazole) with a novel layered structure, was synthesized hydrothermally in the presence of imid...

Two organically templated cadmium borophosphates, (C(4)H(16)N(3))[CdClB(2)P(3)O(12)(OH)] (1) and (C(2)H(10)N(2))[CdB(2)P(3)O(12)(OH)] (2), were synthesized hydrothermally in the presence of structure-directing amines. Compound 1 has a complex layered structure (orthorhombic, Pbca (No. 61); a = 9.470(2), b = 12.307(3), c = 27.311(6) A; V = 3183 (1) A(3); Z = 8) with a 9MR channel system, while compound 2 (orthorhombic, Pbca (No. 61); a = 9.286(3), b = 12.459(3), c = 21.626(6) A; V = 2502(1) A(3); Z = 8) presents a 3-dimensional open framework structure of different types of intersecting channels. It is worth noting that both the Cl(-) anions and the organic templates play important and interesting roles in the formation of the structures.