New luminescent rare earth activated oxynitridosilicates and oxynitridogermanates with the apatite structure

摘要: New luminescent oxynitrides based on the apatite structure doped with Eu2+ and Ce3+ have been prepared by ammonolysis of oxysilicate or oxygermanate precursors. The host compounds general formula La10−xSrx(Si/Ge)6O27−x/2−3y/2Ny. When divalent europium trivalent cerium they present blue, green, yellowish green orange luminescence under UV/blue excitation. Remarkable long wavelength emissions centred beyond 500 nm are observed for activated oxynitridosilicates oxynitridogermanates, compositions La8.9Ce0.1SrSi6N0.37O25.95, La8.9Ce0.1SrSi6N1.06O24.91 (λem = 545 nm) La9.9Ce0.1Ge6N2.46O23.31 590 nm). treatment precursor oxides required cationic ratios in NH3 gas was used as a convenient method to prepare oxynitride materials at moderate temperatures. This allowed decreasing nitriding temperature from 1600–1400 °C 1050–600 respect generally synthesis (oxy)nitride silicates, solid state reaction between oxides, nitrides carbonates N2 N2–H2 flow.