摘要
从能量传递的角度出发,利用同步辐射光源(德国HASYLAB实验室的SUPERLUM I实验站)对Pr3+和Mn2+掺杂的SrB4O7粉末样品进行了光谱研究。206 nm激发下,在SrB4O7∶Pr3+(0.1%,摩尔分数)样品中观察到了来自Pr3+离子1S0能级的光子级联发射。SrB4O7∶Pr3+样品的发射谱与SrB4O7∶Mn2+样品监测Mn2+离子640 nm发射的激发谱在330~430 nm的波长范围里存在显著的光谱重叠。这个光谱重叠有利于Pr3+→Mn2+的能量传递发生,从而将Pr3+离子级联发射中第一步不实用的紫外或近紫外光子转换为Mn2+的红光发射。双掺杂样品SrB4O7∶Pr3+,Mn2+与单掺杂样品SrB4O7∶Pr3+的发射谱比较揭示出Pr3+→Mn2+的能量传递的确存在,并且提供了一种传递效率的估算方法,表明通过“Pr3+-Mn2+”组合有可能获得量子效率大于1的高效真空紫外激发发光材料。
The luminescence of Pr^3＋ or Mn^2＋ singly doped as well as Pr^3＋ and Mn^2＋ codoped SrB4O7 powder microcrystalline samples were investigated using synchrotron radiation. The photon cascade emission originating from the 1S0 level was observed in the SrB4O7： Pr^3＋ （0.1% ,mol fraction） sample upon 206 nm excitation. There are desirable spectral overlaps in the region of 330 -430 nm between the emission spectra of the SrB4O7： Pr^3＋ sample and the excitation spectra of the SrB4O7： Mn^2＋ sample monitoring the Mn^2＋ luminescence at 640 nm. The wavelengths corresponding to transitions ^1S0→^1I6, ^3P2,1,0（405 nm） and ^1S0→^1D2（340 nm） of Pr^3＋ coincide very well with those corresponding to transitions ^6A1g→^4Eg-^4A1g（410 nm） and ^6A1g→^4T2g （350 nm） of Mn^2＋, respectively. These spectral overlaps are in favor of the energy transfer from Pr^3＋ to Mn^2＋, converting the first step photon from Pr^3＋ ：^1S0 in the unpractical ultraviolet or near-ultraviolet regions into the red Mn^2＋ emission. A comparison of the room temperature emission spectra of the SrB4O7 ： Pr^3＋, Mn^2＋ sample with that of the SrB4O7： Pr^3＋ sample revealed the existence of the proposed energy transfer between Pr^3＋ and Mn^2＋. This conclusion about Pr→Mn energy transfer was also supported by the evidences from the low temperature （10 K） spectra and decay curves of 405 nm emission from Pr^3＋ singly doped and Pr^3＋, Mn^2＋ codoped samples. The efficiency of the energy transfer was estimated to be 43% by a simple equation based on the comparison of the emission spectra of the SrB4O7： Pr^3＋, Mn^2＋ sample with that of the SrB4O7： Pr^3＋ sample, thus a 143% quantum efficiency was achieved, suggesting an promising VUV phosphor based on Pr^3＋ and Mn^2＋ combination.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2006年第3期337-342,共6页
Chinese Journal of Luminescence
基金
国家自然科学基金资助项目(50332050
90201019)
