煅烧气氛对均相沉淀法制备YAG∶Ce荧光粉性能的影响

Effect of the Calcination Atmosphere on the Properties of YAG∶ Ce Phosphor Synthesized by Homogeneous Precipitation Method

按照化学计量比Y2.94Ce0.06Al5O12,采用均相沉淀法制备了YAG∶Ce荧光粉的前驱体,并将制得的前驱体分别在空气气氛,惰性气氛(N2)和还原性气氛(CO)下煅烧。采用热分析和X射线衍射图谱研究了产物在煅烧过程中相的演变过程以及最终产物相的组成。结果表明,当在空气中煅烧时,大量Ce3+激活离子被氧化成Ce4+并在基质中析出成为CeO2相;在CO气氛中煅烧的样品中存在中间相(YAM),证明在相同煅烧温度下该气氛不YAG晶相的形成。荧光光谱表明,YAG晶相的形成和Ce3+离子的氧化对样品的发光性能有很大的影响。当在均相沉淀过程中添加聚乙二醇分散剂并在氮气气氛下煅烧后,产物的荧光性能得到大幅度提升。

YAG： Ce precursor was prepared via homogeneous method based on the stoichiometric ratio of Y2.94 Ce0.06 Al5O12. The as-prepared precursor was calcined under air atmosphere, inert atmosphere （ N2 ） and reducing atmosphere （CO）, respectively. The phase evolution process during calcination and the phase of final product were characterized by DSC and XRD. The results show that the CeO2 phase is observed in the sample calcined under air atmosphere due to the oxidation process of Ce^3＋. The intermediate phase （YAM） still exists in the sample calcined under reducing atmosphere, which gives a clue that the crystallization of YAG is inhibited. The photoluminescence spectra confirm that both the crystallization of YAG and the oxidation of Ce^3＋ has an impact on the photoluminescence properties of YAG： Ce phosphor. When the PEG acted as dispersant is added into the sample calcined under N2 atmosphere, the photolmninescence properties improve greatly.