Luminescent Properties of Ba_3MgSi_(2-x)Al_xO_8: Eu~(2+), Mn~(2+) Phosphor for white LED

摘要

Series of Ba_3MgSi_(2-x)Al_xO_8: Eu~(2+), Mn~(2+) phosphors were synthesized by solid-state reaction and X-ray powder diffraction analysis confirmed the formation of the samples. These phosphors have a broad excitation band range from near ultraviolet to blue region (340-460nm). The phosphors have three emission bands peaking at 615nm, 480nm and 420nm respectively under excitation of 380nm irradiation. Two emissions peaking at 420nm and 480nm originated from the 5d to 4f transition of Eu~(2+) ions that occupy two Ba~(2+) sites in the crystal of Ba_3MgSi_(2-x)Al_xO_8. The 615nm emission is attributed to the energy transferring from Eu~(2+) to Mn~(2+). The intensity ratio between the 420nm and 480nm emissions varied with different concentration of Al ions. When the concentrations of the Eu~(2+), Mn~(2+) and Al~(3+) were 0.1mol, 0.1mol and 0.35mol in the phosphor respectively, the phosphor presented intense white emitting under the excitation of 380nm irradiation. The GaN (380nm)-based Ba_2.9Mg_0.9Si_1.65Al_0.35O_8:0.1Eu~(2+) 0.1Mn~(2+) white LED with the CIE coordinate of (0.3085, 0.3139) and color rendering of over 85 was obtained.