双掺Eu3+ 和Tb3+ 的下转换β-NaYF4的合成与发光性能

采用高温溶剂热法合成了下转换发光材料NaYF₄∶Eu³⁺ 和NaYF₄∶Eu³⁺,Tb³⁺ ,采用X射线衍射(XRD)、场发射扫描电镜(FESEM)、激发(PLE)谱和光致发光(PL)谱对材料的物相结构、形貌特征和发光性质进行了表征和研究,并分析了其发光原理。结果表明:所合成的NaYF₄∶Eu³⁺ 和NaYF₄∶Eu³⁺,Tb³⁺ 为纯六方相晶体,尺寸在100 nm左右;改变Eu³⁺ 和Tb³⁺ 的掺杂浓度后晶格结构没有发生明显变化,说明Eu³⁺ 和Tb³⁺ 取代的是Y³⁺的晶格位置;在394 nm光的激发下,检测到Eu³⁺ 在⁵D₀→⁷F₁ 和⁵D₀→⁷F₂跃迁处的特征发射光,并且可见光强度随着Eu³⁺ 离子掺杂浓度的变化而变化。另外Tb³⁺ 离子浓度对NaYF₄∶Eu³⁺ 晶体结构产生了一定的影响,说明掺杂Tb³⁺ 离子改变了Eu³⁺ 离子所处的配位环境,导致红色发光带增强,而这主要源于电偶极子跃迁的贡献。

Synthesis and Luminescence Properties of β-NaYF4 Doped with Eu3+ and Tb3+

Powdered samples NaYF4∶Eu3+ and NaYF4∶Eu3+,Tb3+ are successfully prepared by high temperature solvothermal method.The obtained samples are characterized by X-ray power diffraction(XRD),field emission scanning electron microscopy(FESEM),and photoluminescence(PL) spectra.Experiment results revealed that as-prepared NaYF4∶Eu3+ and NaYF4∶Eu3+,Tb3+ crystallized in hexagonal phase without cubic phase,and the size was about 80 nm×100 nm(side length×thickness).When the doping concentration of Eu3+ and Tb3+are various,the lattice structure of samples do not change,indicating that the Eu3+ and Tb3+ ions are completely dissolved in the NaYF4 host lattice by substitution for the Y3+.The emission from 5D0→7F1(595 nm) and 5D0→7F2(618 nm) of Eu3+ ions was observed under excitation of 394 nm light from Xe lamp.The visible light intensity changes with the doping ions of Eu3+ concentration and the influence to crystal structure of Tb3+ ions concentration have been investigated.These results show that the doping ions of Tb3+ change the coordination environment of Eu3+,resulting to stronger red emissions,and electric dipole transition occupied the main contribution.