共掺La3+对Sr2SnO4∶Sm3+的余辉增强

研究了以La3+离子为辅助激活剂,对Sm3+掺杂的发光材料Sr2SnO4:Sm3+余辉性能的影响。采用传统的高温固相法合成Sr2SnO4∶Sm3+,La3+红色长余辉发光材料。利用X射线粉末衍射仪、荧光光谱仪、热释光剂量仪等手段对粉末样品进行了表征。分析结果表明,在1400℃得到了单相Sr2SnO4,Sr2SnO4∶Sm3+,La3+发光粉末有563、599和646 nm 3个发射峰,与Sm3+单掺杂的Sr2SnO4∶Sm3+相比,其光谱发射峰位没有明显变化。余辉亮度衰减曲线表明适量的La3+掺杂可以延长Sr2SnO4∶Sm3+的余辉时间。通过对热释光谱的分析,解释了双掺杂发光粉余辉性能增强的原因,La3+掺杂增加了更多适宜深度的陷阱(VSr″),可以有效存储光能,增强余辉的时间和强度。

Enhanced Long Persistence of Sr2SnO4:Sm3+ Phosphor by Co-doping with La3+

It is necessary to further improve the afterglow properties of Sr2SnO4∶Sm3+ red afterglow phosphors in consideration of its potential practical applications.In this work,Sr2SnO4∶Sm3+ red afterglow phosphors were prepared via the conventional solid-state reaction route and the enhanced properties were observed when La3+ ions were co-doped.The as-synthesized Sr2SnO4∶Sm3+,La3+ phosphors were characterized by using XRD,photolu-minescence and thermoluminescence spectrascopy.Sr2SnO4∶Sm3+ red afterglow phosphors are pure phase at 1 400 ℃ under atmospheric pressure.The emission spectrum shows that there are at least three peaks located at 563,599 and 646 nm,and the peaks can be assigned to the 4G5/2→6HJ(J=5/2,7/2,9/2) transitions of Sm3+ ion.The presence of La3+ ion does not cause any change in the emission spectrum of samarium.The decay patterns of afterglow curves demonstrate that the afterglow time of Sr2SnO4∶Sm3+ could be extended by the incorporation of La3+.The thermoluminescence glow curve results confirm that the enhanced afterglow properties of Sr2SnO4∶Sm3+,La3+ is comparable to Sr2SnO4∶Sm3+.This implies that the codoping increases more appropriate traps(VSr″) which are in favour of energy storage,higher brightness and longer lasting time.