New long-afterglow phosphors: Yb~(2+)-doped strontium aluminates

摘要

New long afterglow phosphors of Sr_4Al_(14)O _(25):Yb~(2+), Dy~(3+) and SrAl_xO _((1+1.5x)):Yb~(2+) (x = 3, 4, 5) were prepared by sintering the thermally decomposed precursors under reducing condition at 1200-1400°C. The thermally decomposed precursors were obtained by heating either hydroxide or nitrate mixtures at temperatures below 300°C. The phosphor Sr_4Al_(14)O_(25):Yb~(2+), Dy~(3+) showed long afterglow property comparable with the famous phosphor Sr_4Al_(14)O_(25):Eu~(2+), Dy ~(3+) in phosphorescence life time though phosphorescence intensity is weaker than the latter.