Eu‐Doped Barium Aluminum Oxynitride with the β‐Alumina‐Type Structure as New Blue‐Emitting Phosphor

Abstract

Attractive new blue-emitting phosphors for use in low-pressure mercury gas discharge lamps are synthesized by Eu-substitution in the barium aluminum oxynitride host lattice with the -alumina-type structure. The emission spectra of these phosphors for 254 nm excitation show a band at about 450 nm with a shoulder at higher wavelength. The maximum quantum efficiency of these materials is about 85-90% just like commercial BaMgAl 10 O 17 :Eu with the -alumina type structure. The nonoptimized oxynitride phosphors are more sensitive to oxidation (at 873 K) and to short-term depreciation due to 185 nm irradiation compared to commercial BaMgAl 10 O 17 :Eu. However, the maintenance of the oxynitride phosphors in single component fluorescent lamps is improved. Calculations indicate that by using these phosphors in tricolor fluorescent lamps instead of BaMgAl 10 O 17 :Eu with the -alumina type structure, the color rendering index will improve while the lumen output remains high.