【摘要】 以硝酸铈、氧化镧和氧化铕为原料,柠檬酸为络合剂,采用溶胶-凝胶化学法合成了稀土Eu³⁺掺杂的镧铈复合氧化物（镧铈的量比分别为1∶1和1∶2）荧光粉。通过X射线衍射、扫描电镜、拉曼光谱和光致发光等手段研究了不同组成下样品的结构、发光及显色性能。结果表明,所得复合氧化物样品与CeO₂相似,均为立方萤石结构,空间群为Fm3m,但复合氧化物的晶胞参数a大于CeO₂。粉体形貌近似球形,颗粒均匀,粒径范围在50～60 nm之间。在466 nm蓝光激发下,位于613 nm和628 nm处Eu³⁺的⁵D₀→⁷F₂特征红色跃迁为主发射峰。固定Eu³⁺掺杂摩尔分数为15%,镧铈复合氧化物的荧光强度明显优于氧化铈基质,而当基质中镧铈的量比为1∶1时,样品的荧光进一步优化达到最强。由于466 nm对应的蓝光区与半导体GaN芯片的发光重合,这有利于Eu³⁺掺杂的镧铈复合氧化物在固态照明中的应用。更多还原

【Abstract】 The Eu³⁺-doped lanthanum cerium composite oxides（the molar ratio of La to Ce is 1∶1 and 1∶2, respectively） were sol-gel synthesized by using cerium nitrate, lanthanum and europium oxide as raw materials, and appropriate amount of citric acid as chelating agent. The crystal structure, luminescent properties and chromaticity coordinate of the samples with different composition were analyzed through X-ray diffraction patterns, scanning electron microscope, Raman spectra and photoluminescence. The results reveal that the composite samples are of cubic fluorite structure with the space group Fm3m, which is almost identical with CeO₂ except for larger lattice parameter a. The powder morphology shows round shape and the particle sizes are around 50-60 nm. Excited with 466 nm blue light, the characteristic red transition（⁵D₀→⁷F₂） emission of Eu³⁺ at 613 nm and 628 nm plays predominant roles. As the doping concentration of Eu³⁺ is stable at 15%, the luminescence intensity of lanthanum cerium composite is obviously superior to CeO₂, and the luminescence is further optimized as the molar ratio of La to Ce is 1∶1. Due to the coincidence of 466 nm blue light with the emission of GaN chips, the Eu³⁺-doped lanthanum cerium composite oxide may potentially be used in solid state lighting fields.更多还原