Fluorescence in β–Al₂O₃–Like Materials of K, Ba and La Activated with Eu²⁺and Mn²⁺

Abstract

Incorporation of Mn2+ and Eu2+ ions in β-Al2O3-like host crystals has been studied. Under ultraviolet excitation, both BaO·6Al2O3: Eu, Mn and La2O3·11Al2O3: Eu, Mn show intense green fluorescence caused by the energy transfer from Eu2+ to Mn2+. The efficiency of the luminescence is comparable to that of Zn2SiO4: Mn when excited by 254 nm light. Emission and excitation spectra of the phosphors were compared with those of K β-Al2O3. The difference in the atomic packing in the mirror plane of these aluminates appears to be reflected in the emission spectra of Mn2+. The quenching temperature for the sensitized fluorescence of Mn2+ is governed by the Eu2+ ions, replacing mono-, di-, or tri-valent large cations in these compounds.