采用聚乙二醇200辅助的共沉淀法制备了ZnAl2O4:Tb3+绿色荧光粉。通过X射线衍射(XRD)、热重-差热(TG-DTA)和荧光光谱(FL)对合成的ZnAl2O4:Tb3+荧光粉进行了表征。XRD结果显示:合成产物为立方晶系的ZnAl2O4:Tb3+,形成良好晶体的最佳煅烧温度为700℃,与TG-DTA的数据显示一致。ZnAl2O4:Tb3+的激发光谱由260~310 nm的宽带峰和一系列的锐线峰。发射光谱的主发射峰位于544 nm,对应于D4-F5的能级跃迁。研究发现Tb3+的掺杂浓度对样品发射峰的组成强度有着很重要的影响,在Tb3+的摩尔分数为5.8%时达到最大,继续增加Tb3+的浓度,出现浓度猝灭现象。
ZnAl2O4: Tb3+ green phosphors were prepared by an improved co-precipitation method. The crystal structure, phase transition and luminescence properties of as-synthesized ZnAl2O4: Tb3+ phosphors were investigated by X-ray diffraction, TG-DTA and fluorescence spectrometer, respec- tively. XRD results indicate that the crystal structure of the phosphors is cubic phase of ZnAl2O4 and the best temperature for synthesis ZnAl2O4: Tb3+ with cubic structure is 700 ℃. The excitation spectrum is formed by a broad band (260 -310 nm) and a series of sharp peaks. The emission spectrum is composed of several peaks,located at 490, 544, 590 and 624 nm, respectively. The main peak is at 544 nm which is contributed to Tb3+ions transition from s D4 to 7 F5. It is found that Tb3+ concentration has a significant effect on the emission spectrum. When Tb3+ mole fraction is 5.8%, the green emitting is the strongest. However, When Tb3+ mole fraction is more than 5.8%, the luminescence intensity decreases.