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The luminescence properties of strontium aluminate (Sr-Al-O) phosphors change strongly depending on the starting metal composition ratio of strontium oxide (SrO) and alumina (Al2O3). In this study, the starting metal composition effect on blue Sr-Al-O:Eu2+ phosphor synthesized on single crystalline magnesia (MgO) was investigated. The crystal structure and the emission property of the obtained Sr-Al-O:Eu2+ blue phosphors, were independent of the Al2O3/SrO ratio in the raw material. In addition, the obtained emission phases were not contained Al atom. These results indicated the correct starting metal composition for the blue phosphor synthesized on MgO is SrO:Eu. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

A violet divalent europium-doped strontium aluminate ( Sr- Al- O: Eu2+) phosphor particle was synthesized from a metal-ethylenediaminetetraacetic acid ( EDTA) solution of Sr, Al, Eu, and particulate alumina via spray drying and sintering in a reducing atmosphere. The emission properties, crystal structures, cross-sectional emissions, and elemental distributions of the obtained Sr- Al- O: Eu2+ phosphor particles were investigated. The product was determined to be secondary Sr Al12 O19: Eu2+ particles with an average diameter of 20 μm. The violet Sr Al12 O19: Eu2+ emission phase was found in a 1-μm-thick coating of the particles where elemental Al diffusion occurred. These particles are anticipated to find commercial applications such as paints. [ABSTRACT FROM AUTHOR]

Abstract: Y2O3:Eu red phosphor powder was synthesized with powders of metal–ethylenediaminetetraacetic acid (EDTA) complexes as a starting material. The compositional analysis of each metal–EDTA complexes particle and Y2O3:Eu particle was performed using a particle analyzer. In this study, first, the particles of a mixture of Y– and Eu–EDTA complexes were obtained by a spray drying method from solution consisting of Y– and Eu–EDTA·NH4. Then, the metal–EDTA complex powder was fired in obtaining the Y2O3:Eu red phosphor. The metal composition of each particle was scattered for the powder of the metal–EDTA mixture, while it became narrow for the Y2O3:Eu powder. The intensity of cathodoluminescence obtained from the Y2O3:Eu powder increased with increasing the fired temperature. In addition, the maximum intensity was obtained from the sample with x=0.12 for Y2−x O3:Eu x . [Copyright &y& Elsevier]

Abstract: The crystalline state of terbium-containing yttria is one of the important candidates for uses to ultraviolet- and electron-excited green phosphors. To increase the intensity of green emission, structural design of the polycrystalline Y2O3:Tb was carried out using a chemical-vapor-deposition technique operated under atmospheric pressure. The green luminescence intensity was strongly dependent upon the concentration of Tb. The intensity of the photoluminescence at 542nm obtained from 〈100〉 oriented Y2O3:Tb whiskers was higher than that obtained from the uniform Y2O3:Tb polycrystalline film with random orientation. [Copyright &y& Elsevier]

Abstract: Y2O3:(Eu,B) red phosphor was obtained by a thermal decomposition technique of a mixture of yttrium–ethylenediaminetetraacetic acid (Y–EDTA), Eu–EDTA and boric acid. The doping ratio of boron, [B]/([Y]+[Eu]), in the starting material was varied from 0 to 1. The properties of morphology, crystallization behavior, metal composition and photoluminescence of resulting Y2O3:(Eu,B) powder were examined. The Y2O3:(Eu,B) powder had spherical shape with a diameter of 1–5μm with some hollows on the surface. No secondary cohesive particles were seen. X-ray diffractometry revealed that although the crystallinity of powder was improved with addition of small amounts of boron, it decreased with excess amounts of boron. Several peaks indexed as the impurity phases of Y3BO6 and YBO3 were observed on the samples obtained under condition of excess amounts of boron. The photoluminescence intensity observed at 611nm was dependent upon crystallinity of the sample. [Copyright &y& Elsevier]

[Display omitted] • CaAl 4 O 7 : Eu2+, Nd3+ phosphors were synthesized on mortar substrates. • Phosphors showed a blue emission peak at approximately 440 nm. • Rapid quenching in the H 2 -O 2 flame changed the Eu3+ species to Eu2+. Calcium aluminate phosphors were synthesized on mortar substrates using an aqueous solution comprising metal (Al,Eu,Nd)-ethylenediaminetetraacetic acid (EDTA) complexes, followed by treatment with a high-heat hydrogen/oxygen (H 2 -O 2) coupled flame with a variable gas flow rate. The infrastructure functionalization performance of the cement system was evaluated through crystal structure analysis and emission/excitation properties investigation. The emission phase of the calcium aluminates was identified using cathodoluminescence microscopy. The afterglow properties were also investigated. Furthermore, a model for the formation of calcium-aluminate phosphors using a metal-EDTA aqueous solution with H 2 -O 2 flame treatment was developed. [ABSTRACT FROM AUTHOR]

Here we investigate the basic characteristics of the tissue-equivalent phantom thermoluminescence slab dosimeter with synthetic resin type 1 (TEP-TLSD/SR1), a two-dimensional TLD based on TL phosphor Li3B7012:Cu developed by the Urushiyama Research Group. Li3B7O12:Cu has a single glow peak at 120 °C at a heating rate of 0.317 °C s−1. The dose response is linear between 0.1 and 10 Gy. The phosphor, when combined with a synthetic resin, can be molded into 200 mm × 200 mm × 2.5 mm slabs. The system has a Charge Coupled Device (CCD) dependent spatial resolution (pixel pitch) of 640 μm and a pixel response standard deviation of 1.33%. Using simple pixel-based noise compensation, we were able to improve the signal-to-noise ratio (SNR) in the final image. In tests as a TEP, this system gives off axis ratio and percentage dose depth results highly correlated with those of an ion chamber suspended in a water phantom. The TEP-TLSD/SR1 produces similar images to Gafchromic film for X-ray imaging. This TEP-TLSD/SR1 is not only larger than the prototype, but also has a better SNR and improved usability. With further improvements in tissue equivalence, we foresee a system where a TEP and dosimeter are combined into a three-dimensional dosimeter. [ABSTRACT FROM AUTHOR]

Abstract: Chemical stability of 6-coodinated SrO is a fundamental problem when this is used for various applications. In this study, optical and chemical stabilities of 8-coordinated SrO:Eu2+ phosphor were investigated. SrO:Eu2+ phosphor was synthesized from thermal treatment of SrO:Eu powder located on a single crystalline MgO at 1500°C under reduction atmosphere. Obtained 8-coordinated SrO:Eu2+ phosphor exhibit strong blue luminescence and chemical stability in distilled water for 3 days. Our findings prove that obtained 8-coordinated SrO:Eu2+ possesses relative optical and chemical stabilities in water. [Copyright &y& Elsevier]

Abstract: Eu2+-doped SrO (SrO:Eu2+) phosphors were synthesized and their luminescence properties were investigated. Phosphors doped with different Eu2+ concentrations were synthesized by the thermal treatment of SrO and Eu powders on a single crystalline MgO substrate at 1500°C in a reducing atmosphere of Ar and H2. X-ray diffraction measurements showed that the synthesized phosphors contained 8-coordinated SrO with an orthorhombic crystal system. The phosphors showed a strong blue emission at 456nm, which was attributed to the Eu2+ concentration. In addition, a phosphor doped with 2at% Eu2+ showed an internal quantum efficiency of 30%. [Copyright &y& Elsevier]