Near ultraviolet excitable cyan-green phosphors of BaLaAlScO:Ce and BaLaAlScO:Ce,Tb: investigations on the crystal structure, site assignment of Ce and Tb ions, and an energy transfer process from Ce to Tb.

An energy transfer from Ce to Tb is feasible in energy transition processes for the development of optical devices, especially phosphor-converted white LEDs (pc-wLEDs). Most of the energy transfer phosphors co-doped with Ce and Tb, unfortunately, have weak absorption under a near-ultraviolet light of around 405 nm and blue light excitation, making them incapable for use as near ultraviolet or blue LEDs. In this study, novel energy transfer luminescent materials, BaLaAlScO:Ce,Tb, isostructural with existing BaLa(Al,Fe)O, were successfully synthesized through a conventional solid-state reaction as a single phase.

Structure and Luminescence Studies of a Ce-Activated BaLaMgAlO Green-Emitting Phosphor.

Novel green-emitting BaLaMgAlO:Ce (BLMAO:Ce) is successfully obtained by a solid-state reaction. In this study, BLMAO, which is inspired from the BaLaAFeO crystal structure, shows a green emission approximately peaked around 500 nm under near-ultraviolet light excitation at 412 nm by Ce doping. Moreover, internal and external quantum efficiencies of BLMAO:0.

Porous Lanthanide Metal-Organic Frameworks Using Pyridine-2,4-dicarboxylic Acid as a Linker: Structure, Gas Adsorption, and Luminescence Studies.

Two types of new lanthanide coordination networks, [Ln(pdc)(Hpdc)(HO)]·8HO [Hpdc = pyridine-2,4-dicarboxylic acid; Ln = Ce (), Pr (), Sm (), Eu (); type A) and [Tb(pdc)(Hpdc)]·3HO (type B), have been synthesized using a hydrothermal synthetic method. The former type A compound has an unfamiliar architecture, even basically comprised of primitive cubic (pcu) topology, and demonstrate porous gas adsorption behavior, giving several hundreds of square meters per gram surface areas after evacuation of the water molecules, while the latter type B compound does not show any porous properties. Most interestingly, the solvothermal synthetic method using ,-dimethylformamide (DMF) as a solvent gives compounds that crystallize in a structure analogous to that of type A for Ln = La-Ho, probably formulated as [Ln(pdc)(Hpdc)·(DMF)]·DMF.

Single Crystal Growth and Crystal Structure Analysis of Novel Orange-Red Emission Pure Nitride CaAlSiN:Eu Phosphor.

Single crystal of novel orange-red emission CaAlSiN:Eu phosphor was grown by our original vapor phase technique, and the precise crystal structure was investigated for the first time by single crystal X-ray diffraction analysis. The crystal structure of CaAlSiN:Eu single crystal was verified to be an α-SiN-type trigonal structure (space group 31) with = 0.79525(9) nm, = 0.

Structure of tri-aqua-tris-(1,1,1-tri-fluoro-4-oxo-pentan-2-olato)cerium(III) as a possible fluorescent compound.

Luminescence due to the transition of Ce is quite rare in metal-organic complexes where concentrate quenching frequently occurs. One of the possible ways to avoid this is to design an architecture with elongated metal-metal distances. In the structure of the title complex, tri-aqua-tris-(1,1,1-tri-fluoro-4-oxo-pentan-2-olato-κ,')cerium(III), [Ce(CHFO)(HO)], the Ce complex is linked to neighbouring ones by hydrogen bonding.

Bluish-White Luminescence in Rare-Earth-Free Vanadate Garnet Phosphors: Structural Characterization of LiCaMVO (M = Zn and Mg).

Extensive attention has been focused toward studies on inexpensive and rare-earth-free garnet-structure vanadate phosphors, which do not have a low optical absorption due to the luminescence color being easily controlled by its high composition flexibility. However, bluish emission phosphors with a high quantum efficiency have not been found until now. In this study, we successfully discovered bluish-white emitting, garnet structure-based LiCaMVO (M = Zn and Mg) phosphors with a high quantum efficiency, and the detailed crystal structure was refined by the Rietveld analysis technique.

A new lanthanum(III) complex containing acetyl-acetone and 1-imidazole.

In the title complex, di-aqua-(1-imidazole-κ)(nitrato-κ,')bis-(4-oxo-pent-2-en-2-olato-κ,')lanthanum(III), [La(CHO)(NO)(CHN)(HO)], the La atom is coordinated by eight O atoms of two acetyl-acetonate (acac) anions acting as bidentate ligands, two water mol-ecule as monodentate ligands, one nitrate anions as a bidentate ligand and one N atom of an imidazolate (ImH) molecule as a monodentate ligand. Thus, the coordination number of the La atom is nine in a monocapped square anti-prismatic polyhedron. There are three types of inter-molecular hydrogen bonds between ligands, the first involving nitrate-water O⋯H-O inter-actions running along the [001] direction, the second involving acac-water O⋯H-O inter-actions along the [010] direction and the third involving an Im-nitrate N-H⋯O inter-action along the [100] direction (five inter-actions of this type).

Rare-earth-free white emitting Ba2TiP2O9 phosphor: revealing its crystal structure and photoluminescence properties.

A high intensity bluish-white emitting Ba2TiP2O9 phosphor was synthesized by a conventional solid-state reaction method and the precise crystal structure was investigated for the first time by Rietveld refinement analysis. Ba2TiP2O9 has a monoclinic crystal structure with a space group C2/c (no. 15), which is built out of PO4 tetrahedra and TiO5 pyramidal polyhedra connected to form a chain structure along the c-axis.

Material Exhibiting Efficient CO2 Adsorption at Room Temperature for Concentrations Lower Than 1000 ppm: Elucidation of the State of Barium Ion Exchanged in an MFI-Type Zeolite.

Carbon dioxide (CO2) gas is well-known as a greenhouse gas that leads to global warming. Many efforts have been made to capture CO2 from coal-fired power plants, as well as to reduce the amounts of excess CO2 in the atmosphere to around 400 ppm. However, this is not a simple task, particularly in the lower pressure region than 1000 ppm.

Hydrothermal synthesis of meso/macroporous BiVO4 hierarchical particles and their photocatalytic degradation properties under visible light irradiation.

An ordered hierarchical meso/macroporous monoclinic bismuth vanadate (BiVO4) particle was fabricated for the first time by a simple two-step melamine template hydrothermal method followed by calcination. The physiochemical parameters of as-prepared porous materials were characterized by means of X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Raman, Barrett-Emmett-Teller, and UV-vis techniques. The nitrogen adsorption-desorption measurement and pore size distribution curve suggest that meso/macropores exist in these hierarchical microarchitectures.

Long phosphorescent Ca2SnO4 with minuscule rare earth dopant concentration.

Rare-earth doped Ca2SnO4 phosphors were synthesized using a conventional solid state reaction method. The red phosphorescence of Eu(3+) was observed in this system with persistence time. In the as-prepared samples, the doped rare earth ions occupied both Ca and Sn sites in the host lattice.

Redetermination of the low-temperature polymorph of Li(2)MnSiO(4) from single-crystal X-ray data.

Crystals of dilithium manganese(II) silicate were grown under high-temperature hydro-thermal conditions in the system LiOH-MnO(2)-SiO(2). The title compound crystallizes in the β(II)-Li(3)PO(4) structure type. The coordination polyhedra of all cations are slightly distorted tetra-hedra (m symmetry for MnO(4) and SiO(4)), which are linked by corner-sharing to each other.

Combinatorial synthesis of phosphors using arc-imaging furnace.

We have applied a novel 'melt synthesis technique' rather than a conventional solid-state reaction to rapidly synthesize phosphor materials. During a synthesis, the mixture of oxides or their precursors is melted by light pulses (10-60 s) in an arc-imaging furnace on a water-cooled copper hearth to form a globule of 1-5 mm diameter, which is then rapidly cooled by turning off the light. Using this method, we synthesized several phosphor compounds including YAlO:Ce(YAG) and SrAlO:Eu,Dy.