NaLaMgWO6:Sm^3+荧光材料的制备及其热稳定性与发光性能

Synthesis, Thermal Stability and Photoluminescence Properties of NaLaMgWO6:Sm^3+ Phosphors

采用固相法合成了新型白光LED用橙红色NaLa1–xSmxMgWO6荧光粉,并对样品的物相、形貌、发光性质及热稳定性进行了研究。结果表明:NaLaMgWO6具有单斜晶系的复合钙钛矿结构。在406 nm激发下,NaLa1–xSmxMgWO6荧光粉将发射以645 nm为主的发射峰,其对应于Sm3+的4G5/2→6H9/2跃迁。样品发光强度随Sm3+掺杂浓度的增大,先增大后减小,Sm3+的最佳掺杂量为x=0.05。通过对荧光粉的发光浓度淬灭曲线分析,可知Sm3+在NaLaMgWO6基质中是通过电偶极–电偶极的多极矩相互作用的方式来实现能量传递。研究了不同温度下NaLa1–xSmxMgWO6荧光粉的发光特性,通过Arrhenius激活能模型对其温度淬灭过程进行分析,证明Sm3+的4G5/2能级温度淬灭机理为Crossover过程,并计算其热激活能ΔE约为0.326 eV。

A series of orange red-emitting NaLa1–xSmxMgWO6 phosphors were synthesized by a conventional solid–state reaction method.The crystal structure,microstructure,luminescence properties and thermal stability were investigated.The results show that NaLa1–xSmxMgWO6 crystals form in a monoclinic structure with a space group of C2/m.Under an excitation at 406 nm,the emission spectra of NaLa1–xSmxMgWO6 phosphors exhibit a most intense red emission peak at 645 nm,corresponding to the 4 G5/2→6 H9/2 transition of Sm3+.The photoluminescence intensity of the sample firstly increases and then decreases with the increase of Sm3+doping concentration.The optimal concentration of Sm3+appears at x=0.05.The mechanism of energy transfer between Sm3+is proved to be dipole-dipole interaction based on the analysis of the concentration quenching curve.In addition,the temperature quenching behavior was also investigated according to the Arrhenius equation,and the results reveal that the quenching process of 4 G5/2 can be ascribed to the crossover process,and the calculated activation energy is 0.326 eV.