摘要
为研究Yb3+离子浓度变化对Tm3+离子在蓝色波段荧光强度的影响,以NaF和La(NO3)3为原料,采用水热法制备了Tm3+和Yb3+共掺的Tm3+/Yb3+∶LaF3纳米颗粒.用X射线衍射对LaF3纳米颗粒进行表征的结果显示,纳米晶体结构呈六方相.透射电镜的观测结果显示,纳米颗粒样品大小均匀、分散性良好.在波长为800nm的激光激发下,观测到了上转换蓝光发射,其中包括波长为474nm和479nm的较强的荧光辐射(相应的跃迁为1G4→3H6)和波长位于450nm的强度较弱的荧光发射(相应的跃迁为1D2→3F4).通过观测不同Yb3+离子浓度条件下共掺Tm3+/Yb3+∶LaF3样品的荧光光谱,研究了Yb3+离子掺杂浓度对于Tm3+离子的荧光发射的影响,并探讨了产生这种现象的原因.研究结果显示,对于1G4→3H6跃迁产生的荧光发射(474nm),当Yb3+离子浓度增大时,反向能量传递速率的增加导致了荧光强度的增大.然而,当Yb3+离子浓度增大到一定程度时,Yb3+离子激发态能级寿命的减少将引发荧光强度的下降.相比较而言,Yb3+离子的浓度的变化对于1D2→3F4跃迁产生的位于450nm处荧光强度的影响较弱.
In order to investigate the influence of Yb3＋concentration on the up-converted blue fluorescence intensity of Tm3＋ ions,the fluorescent materials of Tm3＋ and Yb3＋ codoped LaF3 nanoparticles are prepared using hydrothermal method with NaF and La（NO3）3 as raw materials.The result of X-ray diffraction shows that the crystal structure of the prepared nanoparticles is hexagonal.The image of the transmission electron microscopy suggents that the particles are uniformly distributed and have a good dispersity.Up-converted blue emissions at 474 nm and 450 nm,which correspond to the transitions of 1G4→3H6 and 1D2→3F4 respectively,are observed when the samples are excited with 800 nm lasers.The influence of Yb3＋ concentration on the fluorescence properties of Tm3＋ ions is investigated by adjusting the Yb3＋ concentration in Tm3＋/Yb3＋：LaF3 nanoparticles.It is found that for fluorescence emission at 474 nm,when the concentration of the Yb3＋ increases,the fluorescence intensity also increases due to inverse energy transfer process.But the fluorescence intensity will decrease after it reaches a certain value.For the fluorescence emission at 450 nm,its intensity does not change obviously with the concentration of Yb3＋ ions,but its fluorescence intensity is increasing firstly and then decrease like 474 nm fluorescence.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2010年第3期508-512,共5页
Acta Photonica Sinica
基金
陕西师范大学大学生开放实验基金
陕西省自然科学基金(SJ08-ZT13)资助
