A novel blue phosphor based on phosphate host matrix, KSrPO4 doped with Eu2+, was prepared by solid state reaction. The phosphor invariably emits blue luminescence with a peak wavelength at 424nm under ultraviolet excitation at 360nm. Eu2+-doped KSrPO4 phosphors show higher thermally stable luminescence which was found to be better than commercially available Y3Al5O12:Ce3+ phosphor at temperature higher than 225°C.

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Substitutional solid solutions of metal hexacyanometalates in which low-spin iron(III) and cobalt(III) ions populate the carbon-coordinated sites were synthesized and studied by powder diffraction including Rietveld refinement, cyclic voltammetry of immobilized microparticles, diffuse reflection vis-spectrometry, and magnetization techniques. The continuous solid solution series of potassium copper(II), potassium nickel(II), and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] show that the substitution of low-spin iron(III) by cobalt(III) in the hexacyanometalate units more strongly affects the formal potentials of the nitrogen-coordinated copper(II) and high-spin iron(III) ions than those of the remaining low-spin iron(III) ions. In the case of copper(II) and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] the peak currents decrease much more than can be explained by stoichiometry, indicating that the charge propagation is slowed by the substitution of low-spin iron(III) by cobalt(III). The Rietveld refinement of all compounds confirmed the structure initially proposed by Keggin for Prussian blue and contradicts the structure described later by Ludi. The dependencies of lattice parameters on composition exhibit in all series of solid solutions studied similar, although small, deviations from ideality, which correlate with the electrochemical behavior. Finally, a series of solid solutions of the composition KNi(0.5)(II)Cu(0.5)(II)[Fe(III)(CN)(6)](1-x)[Co(III)(CN)(6)](x), where both the nitrogen- and carbon-coordinated metal ions are mixed populated and were synthesized and characterized. These are the first examples of solid solutions of metal hexacyanometalates with four different metal ions, where both the nitrogen- and the carbon-coordinated sites possess a mixed population.

The authors report here the enhanced luminescence properties of SrSi 2 O 2 N 2 doped with Eu and M ͑M = Ce, Dy, and Mn͒. The Eu and Eu, Mn-codoped powders were prepared by a solid state reaction at temperatures between 1400 and 1600 °C under H 2 ͑25% ͒ -N 2 ͑75%͒ atmosphere. The Eu, M-codoped Sr 1−x−y Si 2 N 2 O 2 phosphors have the monoclinic structure with lattice parameters a ϳ 15.6 Å, b ϳ 16.2 Å, c ϳ 9.4 Å, and ␤ ϳ 91°. The phosphors can be efficiently excited in the UV to visible region, making them attractive as conversion phosphors for a light emitting diode application. A green-yellow emission was observed for Eu, M-codoped Sr 1−x−y Si 2 N 2 O 2 . The addition of M in the Eu site in SrSi 2 O 2 N 2 remarkably enhances the luminescent intensity by the factor of 144%, 148%, and 168% for Ce, Dy, and Mn, respectively.

Sr 3 ( Al 2 O 5 ) Cl 2 phosphor doped with Eu2+ was prepared by a soli-state reaction. This phosphor emits a broad orange-yellow luminescence with a peak wavelength of 620nm and a full width at half maximum of about 175nm under near-ultraviolet (NUV) excitation at ∼400nm. Yellow light-emitting diodes (LEDs) for general lighting were fabricated by combining Sr3(Al2O5)Cl2:Eu2+ phosphor with an NUV chip. The phosphor-converted LEDs had a color temperature of about 2300K and their color rendering index was 74.