在NaGdF_4:Tm^(3+),Dy^(3+)中Gd^(3+)间的能量迁移及Gd^(3+)-Dy^(3+)能量传递量子效率  

Energy Migration Among Gd^(3+) and Quantum Efficiencies of Gd^(3+)-Dy^(3+) Energy Transfer in NaGdF_4:Tm^(3+),Dy^(3+)

作　　者：刘春旭[1] 刘俊业[1] 吕少哲[1] 窦恺 

机构地区：[1]中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,吉林长春130033 [2]Department of Radiation Medicine,University of Kentucky

出　　处：《发光学报》2007年第4期526-530,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金资助项目(60308008;10174078)

摘　　要：基于量子剪裁基本原理,通过光谱技术研究NaGdF4∶Tm3+,Dy3+在一个真空紫外光子激发下获得两个蓝色光子的可能性。在这种化合物中,量子剪裁通过下转换,即通过应用不同镧系离子间的能量传递进行。通过对Tm 4 f12-4 f115d激发,部分能量从Tm3+离子5d态直接传递给Gd3+,然后在Gd3+-Tm3+之间发生交叉弛豫,剩余能量从Gd3+传递给Dy3+,产生两个可见光子发射,一个来自Tm3+的1G43-H6跃迁,另一个来自Dy3+的4F9/26-H15/2跃迁。主要研究获得以NaGdF4∶Tm3+,Dy3+为基础的新型具有更高效率,更高稳定性和更强真空紫外(VUV)吸收量子剪裁发光粉的可能性。各种光谱技术,如光致发光、激发和衰减等被用来表征不同Dy3+浓度掺杂NaGdF4中Gd3+晶格间能量迁移引起的施主Gd3+和受主Dy3+之间的能量传递。结果表明Gd3+离子之间存在能量迁移,随之交换相互作用引起施主与受主(Gd3+-Dy3+)之间的能量传递。通过Bursh-tein等人关于激发态的弛豫理论,施主-受主能量传递参数kDS可以从Gd3+的6P7/2发射的衰减计算出。Gd3-Dy3+能量传递量子效率也可以得到。NaGdF4∶Tm3+和NaGdF4∶Tm3+,Dy3+是由水热法制备的,NaGdF4∶Dy3+是由文献[4]方法制备的。发射光谱和激发光谱通过自制的VUV光谱仪和F-4500测量。衰减曲线由OPO激光器激发获得Gd3+-Dy3+之间能量传递量子效率在受主浓度大约在NA=0.6%时达到最佳值,并且明显地观测到浓度猝灭效应。The possibility to obtain two blue photons under excitation of one VUV photon in NaGdF4： Tm^3 ＋ , Dy^3 ＋ has been investigated by means of spectroscopic techniques, based on quantum cutting principle. In this compound visible quantum cutting is achieved through downconversion, i. e. , by making use of energy transfer between different lanthanide ions. Upon VUV excitation in the 4f^105d levels of Tm^3＋ , part of the energy is transferred directly from the Tm^3＋ 4f^105d states to Gd^3＋. The cross-relaxation between Gd^3＋ -Tm^3＋ is followed, and then the left energy is transferred from Gd^3＋ to Dy^3＋. Two visible photons are yielded： one from Tm^3＋ due to 1 ^G4→3^H6 transition, and one from Dy^3＋ due to 4^F9/2→6^H15/2 transition. In this paper, the possibility to obrain a new quantum cutting phosphor with on NaGdF4： Tm^3 ＋ , Dy^3 ＋ has been inves sion, excitation, decay, etc. were perfo higher efficiency, higher stability and higher VUV absorption based tigated. The spectroscopic techniques rmed to characterize the donor Gd^3＋ transfer preceded by energy migration among Gd^3＋ lattices Dy^3＋ ions. It is shown by the results that the Gd^3＋-Dy^3＋ , including luminescent emision-acceptor Dy^3＋ ion energy in NaGdF4 doped with different concentrations of transfer preceded by energy migration among the Gd^3＋ ions is mainly governed by the exchange interaction. By the theory on excited state relaxation processes, which was developed by Burshtein et al. , the donor-acceptor energy transfer parameter kDA Can be calculated from the 6^P7/2 emission decay of Gd^3＋. The quantum efficiency of Gd^3＋ -Dy^3＋ energy transfer was derived as weU. Powders of NaGdF4： Tm^3＋ （1.5%） and NaGdF4： Tm^3＋ （1.5%）, Dy^3＋ （0.3%） were prepared by the hydrothermal technique, and NaGdF4： Dy^3＋ （0.3%, 0. 6%, 1%, 3% and 5 % ） by the method described in Ref. [4]. The emission and excitation spectra were measured by home-made VUV spectrometer and F4500 monochromator. The

关 键 词：NaGdF4:Tm3+ Dy3+ 能量的迁移和传递 交叉弛豫 量子效率 

分 类 号：O482.31[理学—固体物理]