Influence of excitation wavelengths on luminescent properties of Sr3Al2O6:Eu2+, Dy3+ phosphors prepared by sol–gel-combustion processing

Eu2+ and Dy3+ ion co-doped Sr3Al2O6 red-emitting long afterglow phosphor was synthesized by sol–gel-combustion methods using Sr(NO3)2, Al(NO3)3·9H2O, Eu2O3, Dy2O3, H3BO3 and C6H8O7·H2O as raw materials. The crystalline structure of the phosphors were characterized by X-ray diffraction, luminescent properties of phosphors were analyzed by fluorescence spectrophotometer. The effect of excitation wavelengths on the luminescent properties of Sr3Al2O6:Eu2+, Dy3+ phosphors was discussed. The emission peak of Sr3Al2O6:Eu2+, Dy3+ phosphor lays at 516 nm under the excitation of 360 nm, and at 612 nm under the excitation of 468 nm. The results reveal that the Sr3Al2O6:Eu2+, Dy3+ phosphor will emit a yellow–green light upon UV illumination, and a bright red light upon visible light illumination. The emission mechanism was discussed according to the effect of nephelauxetic and crystal field on the 4f65d1 → 4f7 transition of the Eu2+ ions in Sr3Al2O6. The afterglow time of (Sr0.94Eu0.03Dy0.03)3 Al2O6 phosphors lasts for over 600s after the excited source was cut off.