BaY_2ZnO_5:Tm~(3+)/Yb~(3+)荧光粉的试验优化设计合成及发光性质研究

为了获得BaY_2ZnO_5:Tm~(3+)/Yb~(3+)荧光粉材料的最大蓝色上转换发光强度,采用正交试验设计与二次通用旋转组合设计相结合的两步连续优化法对Tm~(3+)和Yb~(3+)掺杂浓度进行全局优化,得到该体系最强蓝光发射下的离子掺杂最佳浓度.采用高温固相反应法合成出蓝色上转换发光强度最强的BaY_2ZnO_5:Tm~(3+)/Yb~(3+)荧光粉材料,并对样品的晶体结构和上转换发光性质进行了研究.980nm红外光激发下,测量了最优样品在不同激发电流下的上转换发射光谱,由强度制约关系确定样品的蓝色上转换发光为三光子过程.测量了最优样品温度相关的上转换发射光谱,发现样品的蓝色上转换发光强度随着样品温度的升高而持续减弱,即发生了温度猝灭现象,计算得激活能约为0.602eV.

Experimental optimal design on BaY2ZnO5: Tm3+/Yb3+ phosphor and its up-conversion luminescence property

To obtain a maximal blue up-conversion luminescence of Tm³⁺/Yb³⁺ co-doped BaY₂ZnO₅ phosphors, orthogonal experimental design combined with quadratic general rotary unitized design method is employed to optimize the Tm³⁺ and Yb³⁺ ions doping concentration. Two sets of BaY₂ZnO₅:Tm³⁺/Yb³⁺ phosphors are synthesized by the traditional high temperature solid reaction method. The doping concentration ranges of Tm³⁺ and Yb³⁺ are first narrowed by orthogonal experimental design, and then quadratic general rotary unitized design is performed and one regression equation is established based on the experimental results from the latter design. The theoretical maximum value of the blue up-conversion luminescence intensity and the optimal Tm³⁺ and Yb³⁺ doping concentrations are obtained by genetic algorithm. The optimal sample is synthesized and its crystal structure and up-conversion luminescence properties are investigated. It is found that the blue up-conversion luminescence originates from three photon processes under 980 nm excitation. Temperature dependent up-conversion luminescence spectra of the optimal sample show that the blue up-conversion luminescence intensity declines with increasing temperature, implying the occurrence of thermal quenching of up-conversion luminescence. The calculated excitation energy is about 0.602 eV.