【摘要】 控制不同的烧结条件,制备了Eu3+掺杂La2O3 3B2O3体系的晶体及玻璃材料。在这两种组分相同但物相不同的基质中,Eu3+离子表现出不同的光谱性质。通过对比两种材料的发射光谱、声子边带、电荷迁移带及荧光寿命,讨论了Eu3+离子周围局域结构的改变对其发光性质的影响。更多还原

【Abstract】 The local structure of rareearth ions in solid host is of great research interest for designing new luminescence materials, and Eu3+ ion is a good probe to reflect the local environment around rareearth ions in different materials. In this paper, Eu3+doped La2O33B2O3 crystal and glass samples were prepared by solidstate reaction under different calcination temperatures. By controlling calcination temperatures at 960℃ and 1 200℃, respectively, the crystal and glass samples with the same composition were obtained. The Eu3+ ions in the two samples present different flourescent properties. With the excitation of 394nm ultraviolet light, the glass sample presents an intense 618nm emission, while the crystal sample gives a dominant 696nm emission. The emission spectra, the phonon sideband spectra, the charge transfer bands and the lifetimes were measured to clarify the different luminescence of the two samples. In the emission spectra, both of the two figures (Fig1, Fig2) present the characteristic luminescence of Eu3+ ion, including emission peaks at 590nm (5D0→7F1), 618nm (5D0→7F2) , 650nm (5D0→7F3), 696nm (5D0→7F4). Among these transitions, the 5D0→7F1 transition is a magnetic dipole transition, and the 5D0→7F2 transition is an electric dipole transition. It was found that, with the transition from crystal phase to glass phase, the intensity ratio of 5D0→7F2 to 5D0→7F2 of Eu3+ ion was enhanced, which indicates that the value of JO parameter Ω2 was increased. The local structures around Eu3+ ion in the two different host were investigated by measuring the charge transfer bands and the phonon sideband spectra associated with the 5D2←7F0 transition. It was concluded that B-O vibrational mode inside the various borate rings and nonbridging B-O-1 bonds stretching mode with phonon energy of 1 900, 1 500cm-1, respectively, exist in both of the two samples. The charge transfer bands confirmed that the near coordination ions of Eu3+ are different in the two samples.更多还原