Mn2+激活六角铝酸盐CeMgAl11O19-SrAl12O19固溶体的光谱学性质

本文研究(1-x)CeMgAl11O19-xSrAl12O19:Mn2+固溶体光谱学性质。Mn3+在固溶体中的荧光光潜由516nm绿色发射带和630-685nm红色发射带组成。前者归于占据4f格位的四面体Mn2+(g)离子,后者归于位于20格位的八面体Mn2+(r)中心。Mn2+(r)红色发射带随SrAl12O19含量增加而短移,x=0时,为685nm,x=0.8时,短移为630nm。固溶体中Ce3+-Mn2+(g和r)和Mn2+(g)-Mn2+(r)存在能量传递。荧光衰减分析表明,Mn2+(g)-Mn2+(r)能量传递是一种电偶极-电偶极相互作用的直接能量传递。随着固溶体中SrAl12O19含量的增加,Mn2+(g)-Mn2+(r)能量传递几率降低,临界距离R0减小。当x=0.8时,Mn2+(g)-Mn2+(r)传递消失。与之相反,Ce3+-Mn2+(g)能量传递则随SrAl12O19量的增高而加大。当x=0.8时,固溶体0.2CeMgAl11O19-0.8SrAl12O19:Mn2+中Ce2+-Mn2+(g)传递几率仅略低于商用荧光粉CeMgAl11O19中Ce3+-Tb3+传递几率。这类固溶体是有效的绿色发射荧光体。Mn2+格位(4f和2a)的晶场强度10Dq和Racah参数比C/B随SrAl12O19增加而呈减小趋势。本文表明,固溶体结构的镜面层对晶体光谱性质有大的影响。

SPECTROSCOPIC PROPERTIES OF THE Mn2+ DOPED CeMgAl11O19-SrAl12O19 SOLID SOLUTION

The spectroscopic properties of the solid solutions(1-x) CeMgAl11O19-xSrAl12O19:Mn2+ are reported. The fluorescent spectra of Mn2+ in the solid solutions consist of two emission bands, a green band peaked at with 516nm and a red band, the peak position of which depends on x, with 685nm for x=0 and 630nm for x=0.8. The green band arised from Mn2+ centers in tetrahedral 4f sites (denoted as Mn2+ (g)) and the red band originated from Mn2+ ions in octahedral 2a position (Mn2+(r)).The fluorescence decay analysis and excitation spectra indicated that the energy transfer from Mn2+ (g) to Mn2+(r) occurred in the solid solutions (1-x) CeMgAl11O19-xSrAl12O19 doped with higher Mn2+ concentration (≥0.4mole).