Eu^(3+)掺杂Na_2La_2Ti_3O_(10)红色荧光粉的光谱性质

Luminescence properties for Eu^(3+) doped Na_2La_2Ti_3O_(10) bred phosphors

采用传统高温固相法制备了不同Eu3+浓度掺杂的Na2(La1-xEux)2Ti3O10荧光粉,研究了Eu3+浓度对样品结构及发光性质的影响。X射线衍射(XRD)结果表明Eu3+掺杂浓度不大于40%的样品为四方相Na2La2Ti3O10;当Eu3+浓度达到60%时,出现了正交相NaEuTiO4。对样品进行激发、发射光谱的测试发现,样品可被较宽波段的紫外光有效激发,获得明亮的红橙色光发射,且Na2La2Ti3O10到Eu3+存在有效的能量传递。利用Van模型,证实了Eu3+间的交换相互作用是引发浓度猝灭的主要原因。利用Auzel模型,解释了Eu3+发光的自猝灭行为。测试了样品在不同温度下的发射光谱和时间衰减曲线,确定样品发光产生温度猝灭的主要机理是Crossover过程。利用Arrhenius公式对实验数据进行拟合,确定激活能值约为0.26eV,说明Na2(La1-xEux)2Ti3O10荧光粉具有较好的发光热稳定性。

Na2 a traditional La2Tia O10 red phosphors with various Eu3＋ concentrations were successfully prepared via high temperature solid state reaction method. The influence of Eu3＋ concentration on the properties and the crystal structure of Na2 （Lal-x Eux）2TiaO10 phosphors are investiga- ted. XRD results indicate that the samples doped with 0-40% Eua＋ exhibit tetragonal phase Na2La2TiaO10 ,while when Eu3＋ concentration reaches 60%, another orthorhombic phase NaEuTiO4 appears. The excitation and emission spectra for the samples are investigated. It is found that the prod- ucts could be effectively excited by a broad band in ultraviolet region, whieh indicates an efficient energy transfer from Naz La2 Ti3 O10 host to Eu3＋ ions. Meanwhile,bright orange-red light emissions are detec- ted with ultraviolet light excitation. Based on the Van model, exchange interaction of Eu3＋ ions is con- firmed to be the main reason for the concentration quenching. The reason why self-generated quenching process of Eu3＋ occurs is explained based on Auzelrs model. Besides, the temperature dependent emission spectra and fluorescence decay curves are measured. And the results reveal that thermal quenching be- havior could be ascribed to the crossover process, and the activation energy is calculated to be 0. 26 eV by the Arrhenius model. The results show that the luminescence of Eu3＋ doped Na2 La2Tia O10 red phos- phors has a good thermal stability.