可用于白光照明的单一基质荧光粉(Sr_(0.95)Mg_(0.05))_3(PO_4)_2:Eu^(2+)的发光特性

Luminescence properties of a novel single-phase phosphor(Sr_(0.95)Mg_(0.05))_3(PO_4)_2:Eu^(2+) for white light emitting diodes

采用高温固相法合成系列Eu^(2+)掺杂的单一基质的白光荧光粉(Sr_(0.95)Mg_(0.05))_3(PO_4)_2.该荧光粉可有效被270~390nm的紫外光激发,激发波长范围与紫外LED芯片相匹配.在激发波长为350nm时,发射光谱中有两个发射峰,峰值分别位于410nm和570nm,对应于Eu^(2+)的4f65d1→4f7跃迁,是Eu^(2+)占据了基质中Sr^(2+)的十配位和六配位的两种不同的格位后,形成的两个发光中心.当Eu^(2+)的掺杂浓度为1mol%时,具有最大的发光强度,继续增加Eu^(2+)的浓度后,会出现浓度猝灭现象.通过将Eu^(2+)的掺杂浓度从0到0.01,可以使该荧光粉的CIE色坐标从(0.259 5,0.198 7)的蓝光区域逐渐移动到(0.324 5,0313 3)的白光区域.基于实验结果和理论分析计算表明,这种荧光粉是一种潜在的用近紫外光激发产生白光LED的荧光粉.

A series of single-phase white-light-emitting,Eu^2＋-doped（Sr_（0.95）Mg_（0.05））_3（PO_4）_2 phosphors were synthesized by the traditional solid-state reaction method.This phosphor could be effectively excited by UV light in the range of 270 to 390nm,which matched well with that of ultraviolet LEDs.Under the excitation of350 nm,this phosphor exhibited two broad emission bands,with peaks of 410 nm and 570 nm,which originated from two luminescence centers,related to 4f65d1→4f7 transition of Eu^2＋occupying the tencoordination Sr sites and six-coordination Sr sites,respectively.The emission intensity increased gradually with increasing Eu^2＋ions content up to a maximumxvalue of 1mol%,after which it decreased because of the concentration quenching.The CIE chromaticity coordinates of the prepared double-emitting（Sr_（0.95）Mg_（0.05））_3（PO_4）_2：Eu^2＋phosphor could shift from blue（0.259 5,0.198 7）to white area（0.324 5,0.313 3）by changing the Eu^2＋doping concentration from 0to 0.01.Based on experimental results and theoretical calculation,the luminescence characteristics indicate that this phosphor has great potential to serve as an attractive candidate in the application of n-UV excited white LEDs.