NaSr_4B_3O_((9-3x/2))N_x:Eu^(2+)红色荧光粉制备及发光性能的研究

Luminescent Properties of Red-Emitting NaSr_4B_3O_((9-3x/2))N_x:Eu^(2+) Phosphor for White-LEDs

实验通过传统的高温固相合成法合成了一系列的NaSr_4B_3O_((9-3x/2))N_x:Eu^(2+)红色荧光粉。NaSr_(3.98)B_3O_((9-3x/2))N_x:Eu^(2+)荧光粉具有立方相晶体结构,空间群为Ia-3d,其结构内拥有两个不同配位的发光中心分别为八配位和六配位。NaSr_(3.98)B_3O_((9-3x/2))N_x:Eu^(2+)荧光粉的激发光谱可以与近紫外LED芯片很好地符合,由于Eu^(2+)离子的4f65d1→4f7能级跃迁,使得NaSr_4B_3O_((9-3x/2))N_x:Eu^(2+)荧光粉表现出发光中心位于610 nm附近的红色宽带发射,半高宽约为110 nm。NaSr_(3.99)B_3O_(8.1)N_(0.6):0.02Eu^(2+)荧光粉的最佳掺N浓度为x=0.8,其寿命在两个不同的发光中心的平均衰减时间分别为603和510 ns。在y=0.02时,NaSr_(4-y)B_3O_(8.1)N_(0.6):yEu^(2+)荧光粉的发射光谱发生了浓度猝灭现象,计算得到其激活剂离子间的临界距离为2.712 nm,导致浓度猝灭的激活剂离子之间的相互作用的方式为偶极子-偶极子。以上结果表明,NaSr_4B_3O_((9-3x/2))N_x:Eu^(2+)荧光粉有望成为白光LED的光色转换材料。

An Eu^2＋ -activated oxynitride NaSr4B3O（9-3x/2）Nx ：Eu^2＋red-emitting phosphor was synthesized by solid- state reactions. The synthesized phosphor crystallized in a cubic system with space group 1a-3d. The NaSr4B3O（9-3x/2）Nx ：Eu^2＋ phosphors exhibited a broad red emission band with a peak at 610 nm and a full width at half maximum of 110 nm, which is ascribed to the 4f^65d^1→4f^7 transition of Eu2＋. The optimal doped nitrogen concentration was observed to be x = 0.6. The average decay times of two different emission centers were estimated to be 603 and 510 ns in the NaSr3.99B3O8.1N0.6：0.01Eu^2 ＋ phosphors, respectively. Concentration quenching of Eu^2＋ ions occurred at y = 0.02, and the critical distance was determined as 2.712 nm. The non-radiative transitions via dipole-dipole interactions resulted in the concentration quenching of Eu^2＋ -site emission centers in the NaSr4B3O9 host. These results indicated that NaSr4B3O（9-3x/2） Nx ：Eu^2＋ phosphor was promising for application in white near- UVLEDs.