溶胶凝胶法制备的Y_3Al_5O_(12):Tb^(3+),Ce^(3+)的光学性能及能量传递研究

Luminescent Properties and Energy Transfer of Y_3Al_5O_(12):Tb^(3+),Ce^(3+) Prepared by Polymer-Assited Sol-Gel Method

用溶胶凝胶法制备了一系列不同掺杂浓度的Y3Al5O12(YAG):Tb3+,Ce3+荧光粉,对其物相、光学性能和能量传递进行了研究。多晶粉末X-射线衍射结果表明,所有样品均为YAG晶相,没有其它杂相。当样品在Tb3+的特征激发峰273 nm激发时,除了Tb3+的特征发射外,还观察到位于467 nm的YAG基质的电荷迁移带、位于520 nm的Ce3+的2D3/2,5/2→2F5/2,7/2跃迁,这说明可能存在Tb3+到Ce3+的单向非辐射能量传递。通过监测共掺样品520 nm的发光,得到273 nm的激发峰,使得Tb3+(5D3)到Ce3+(2Di,i=5/2,3/2)的单向非辐射能量传递得到验证;并且随着掺杂Tb3+浓度的增大,273 nm激发峰增强。同时,Ce3+掺杂YAG:Tb3+并没有使Tb3+发光增强,相反YAG:Tb3+,Ce3+中Tb3+发光与YAG:Tb3+相比有1个数量级的减弱,造成这种情况的可能原因,一是Tb3+到Ce3+的单向非辐射能量传递,使得Tb3+发光减弱;二是Ce3+掺杂YAG:Tb3+后基质所多吸收的能量传给了Ce3+而非Tb3+。

A series of Y3Al5O12（YAG）：Tb3＋,Ce3＋ phosphors were synthesized through polymer-assisted sol-gel method,and their phase,luminescent properties and energy transfer were analyzed.XRD Study of polycrystalline powder showed that all samples were of YAG phase without impurity.Excited by 273 nm which was characteristic excitation of Tb3＋,apart from Tb3＋ characteristic emission,charge transfer in YAG host at 467 nm and 2D3/2,5/2→2F5/2,7/2 transfer of Ce3＋ at 520 nm were observed which suggested that one way nonradiation energy transfer from Tb3＋ to Ce3＋ might exist.When monitoring 520 nm emission,273 nm peak was obtained,confirming the one way energy transfer from Tb3＋to Ce3＋.And as Tb3＋ concentration increased,273 nm peak was enhanced.Tb3＋ Luminescence in YAG：Tb3＋,Ce3＋was weakened by one order of magnitude compared with that in YAG：Tb3＋.There were two possible reasons for this as follows： one was that energy transfer from Tb3＋ to Ce3＋ which reduced the emission intensity of Tb3＋,the other was that more energy absorbed by host in Ce3＋ codoped YAG：Tb3＋ was transferred to Ce3＋ rather than Tb3＋.