Sr_2Si_5N_8∶Eu^(2+)荧光粉的制备与发光性能

Preparation and Photoluminescence Properties of Sr_2Si_5N_8∶Eu^(2+) Phosphors

以α-Si3N4,SrCO3,Eu2O3为原料,采用碳热还原氮化法制备了Sr2Si5N8∶Eu2+荧光粉。研究了材料的结构与光谱特性,分析了影响材料发光性能的工艺因素。结果表明,石墨粉含量和助熔剂的用量对Sr2Si5N8相的形成和发光性能有重要影响。当nC/nSr=1.5,助熔剂用量为4wt%时,合成样品的主晶相为正交晶系Sr2Si5N8,在400～550nm可见光激发下,可发射峰值波长位于609nm荧光。激发带的位置与Eu2+离子浓度无关,为400～550nm之间的宽带激发;但发射强度随Eu2+离子浓度的增加而增加,Eu2+离子浓度达到5mol%时发射强度达最大值,在Eu2+离子浓度为2mol%～5mol%之间,观察到发射峰的红移现象。

Eu2＋-doped Sr2Si5N8 phosphors were prepared by the carbothermal reduction and nitridation （CRN） method using the α-Si3N4, SrCO3 and Eu2O3 as the starting materials. The structure and spectroscopic properties were studied. The influencing factors on luminescence properties were analyzed. The results indicate that the contents of graphite powders and fluxing agents have great influence on the phase formation and luminesence properties. The orthorhombic Sr2Si5N8 was obtained with nC/nSr=1.5 and flux 4wt% showing a broad emission band peaking at 609 nm when exciting at 400～550 nm. The shape and position of excitation band are not greatly influenced by the Eu2＋ ions contents. However, the emission intensity increases with increasing Eu2＋ ions content and reaches its maximum with Eu2＋ ions at 5mol%. Meanwhile the red-shift of the emission peaks was observed for the samples of Eu2＋ ions at 2mol%～5mol/%.