NaLa(MoO4)2∶Eu3+/Tb3+/Tm3+材料的合成、发光及能量传递

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采用微乳液‐水热法合成一系列NaLa(MoO4)2∶Eu3+/Tb3+/Tm3+单/共掺的荧光粉(NLM )。采用X射线衍射(XRD)、扫描电子显微镜(SEM )、荧光光谱对荧光粉的晶体结构、形貌特征和发光性质进行了测试和研究。结果表明:所制备的样品均为四方晶系单晶,Eu3+,Tb3+,Tm3+均以取代的方式进入La3+的格位;样品的形貌为四方片状结构,颗粒尺寸1~1.5μm ;当Eu3+掺杂浓度为是9%时,NLM ∶9% Eu3+荧光粉在616 nm发射峰是最强的,此时在NLM基质中Eu3+之间的临界传递距离(Rc)约为15.20?。在NLM∶9% Eu3+的发射光谱中,591 nm处的发射峰为Eu3+的5 D0→7 F1的磁偶极跃迁;616 nm处的发射峰为Eu3+的5 D0→7 F2的电偶极跃迁,电偶极跃迁发射强度约是磁偶极跃迁强度的10倍,表明Eu3+位于无反演对称中心格位。采用固定Eu3+(T b3+)的浓度,改变T b3+(Eu3+)浓度的方法,研究了Eu3+与T b3+之间的能量传递机理。通过调节Eu3+,T b3+和T m3+的掺杂浓度,实现在单一基质条件下可见光区域的光色调节,在360 nm激发下NLM ∶ x% Eu3+,y% Tb3+,z% Tm3+荧光粉的发光由蓝光(0.205,0.135)调到伪白光(0.305,0.266)。“,”A series of Eu3+ /Tb3+ /Tm3+ single/co‐doped NaLa(MoO4 )2 (NLM ) phosphors have been synthesized by microemul‐sion‐hydrothermal method .Phosphor crystal structure ,morphology and luminescent properties were tested and studied by X‐ray diffraction (XRD) ,scanning electron microscopy (SEM ) and fluorescence spectroscopy .The results show that the prepared samples are all tetragonal single crystals .By way of substitution ,the sites of La3+ are replaced by Eu3+ ,Tb3+ and Tm3+ .Mor‐phology of the samples are tetragonal sheet structure and the size of particles is 1~1.5 μm .When the doping concentration of Eu3+ is 9% ,NLM ∶9% Eu3+ phosphor emission peak is the strongest at 616 nm ,the critical transfer distance (Rc ) between Eu3+ in the NLM matrix is about 15.20 ? at this time .At the emission spectrum of NLM∶9% Eu3+ ,the peak at 591 nm is the magnetic dipole transition of 5 D0 to 7F1 of Eu3+ .The peak at 616 nm is the electric dipole transition of 5 D0 to 7 F2 of Eu3+ . Electric dipole transition emission intensity is about 10 times of the strength of the magnetic dipole transition .This indicates that Eu3+ is located at noninversion symmetry site .By Fixing Eu3+ (Tb3+ ) concentration and varying the concentration of Tb3+(Eu3+ ) ,the energy transfer mechanism between Eu3+ and Tb3+ was studied .By adjusting the Eu3+ ,Tb3+ and Tm3+ doping concentrations ,tunable luminescence of visible light region is implemented under the single matrix .The luminescence of NLM∶x% Eu3+ ,y% Tb3+ ,z% Tm3+ phosphors are translated from blue (0.205 ,0.135) to pseudo‐white (0.305 ,0.266) under 360 nm irradiation .
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