白光LED用K_2Ba(WO_4)_2∶Sm^(3+)红色荧光粉的制备与表征

Synthesis and Characterization of K_2Ba(WO_4)_2∶Sm^(3+) Red Phosphor for White Light LED

采用高温固相法合成了一种新型K2Ba(WO4)2∶x Sm3+红色荧光粉。通过XRD、SEM和荧光分光光度计对样品的结构、形貌和发光性能进行了研究。结果表明:该荧光粉具有三方晶系结构,在402 nm处有较强的激发峰,与近紫外LED芯片相匹配。在402 nm激发下,出现了Sm3+的4G5/2→6HJ(J=5/2,7/2,9/2,11/2)的特征跃迁,最强峰位于602 nm处,对应于Sm3+的4G5/2→6H7/2跃迁。Sm3+的最佳掺杂量为x=0.02,且Sm3+之间的临界距离为2.776 nm,浓度猝灭的机理为电偶极-电偶极相互作用。

A novel K2Ba（ WO4）2∶ Sm3 ＋red phosphors were synthesized by high temperature solid state reaction. The crystal structure,morphology and luminescent properties were investigated by XRD,SEM and photoluminescence spectra,respectively. The results show that the phosphors belong to rhombohedral crystal structure,and exhibit strong excitation spectra at 402 nm,which matches well with near-UV LED chips. Upon excitation at 402 nm,the4G5 /2→6HJ（ J = 5 /2,7 /2,9 /2,11 /2） transitions of Sm3 ＋are observed,and the strongest peak locates at 602 nm corresponding to the4G5 /2→6H7 /2transition of Sm3 ＋.The optimized concentration of Sm3 ＋is found to be x = 0. 02 and the critical distance of Sm3 ＋is obtained to be about 2. 776 nm. The concentration quenching mechanism is the electric dipole-electric dipole interaction.