白光LED用蓝绿色荧光粉Sr1-xBax Al2O4:Eu2+的发光性质

采用高温固相法在还原气氛中合成Sr1-xBaxAl2 O4:Eu2+荧光材料.XRD显示,当钡掺杂量x＜0.4时,对应样品主要为单斜SrAl2 O4晶体结构；当x≥0.4时,对应样品主要为简单六方BaAl2 O4晶体结构.在360nn激发下,样品的发射光谱随x的增加由单一的绿光发射(λmax=516nm)逐渐转变为蓝绿...

Luminescence Properties of Blue-green Phosphors Sr_(1-x)Ba_xAl_2O_4:Eu~(2+) for White LED

Sr_1-xBa_xAl₂O₄∶Eu²⁺ phosphors were synthesized in a reducing atmosphere by high temperature solid state method at 1 350 ℃. The patterns of XRD indicated that the crystal structure of the phosphors are the monoclinic phase of SrAl₂O₄ when x<0.4 and the simple hexagonal phase of BaAl₂O₄ when x≥0.4 because of crystal lattice expands with Ba²⁺ ion substitution for Sr²⁺ ion. Photoluminescence experiments were carried out to study the luminescence properties of the phosphors excited under 360 nm. The results showed that emission spectra gradually changed from single green emission (λ_max=516 nm) to blue-green dual-emission (λ_max1= 441 nm, λ_max2=486 nm) with the increase of x. When x was 0.5, there was a better property in Sr_0.5Ba_0.5Al₂O₄∶Eu²⁺. From the relationship between the concentration of Eu²⁺ ion and the intensities of emissions in Sr_0.5Ba_0.5Al₂O₄∶y%Eu²⁺, we get that the maximum dual-emission intensity when y=0.29%. There exist a concentration quenching effect in Sr_0.5Ba_0.5Al₂O₄∶Eu²⁺, and the study points out that the mechanism of concentration quenching effect is electric dipole-dipole interaction.