纳米GdPO4：Eu3+的合成和光谱特性

采用EDTA二钠盐参加的共沉淀方法制备出纳米GdPO₄:Eu³⁺,利用X射线衍射,荧光光谱和电镜等测试手段对GdPO₄:Eu³⁺的相结构和发光性质进行了研究。XRD图谱结果表明700℃合成了纯的具有单斜晶系、独居石结构的纳米GdPO₄:Eu³⁺。根据Scherrer公式计算,700,800℃热处理后样品的一次颗粒度分别为18,40nm左右。激发光谱和发射光谱的研究表明,电荷迁移态和Eu³⁺的特征发射峰的强度随GdPO₄:Eu³⁺纳米粒子的增大而增强。在较小的纳米粒子中,存在结构扭曲的现象,315nm激发下的发射光谱研究表明,Gd³⁺和Eu³⁺具有较好的能量传递。

Synthesis and Spectra Properties of Nanocrystalline GdPO4: Eu3+

Rare earth doped nanocrystalline phosphors have attracted great interest.The main work concerns the synthesis and the spectral changes of nanoparticles.It has been found that many gadolinium compounds doped with Eu³⁺ have a higher luminous efficient due to high efficient energy transfer from Gd³⁺ to Eu³⁺ ions, moreover,PO₄³⁺ groups show high Absorption in VUVregion,thereby,GdPO₄:Eu³⁺could be applied to plasma display panels.Nanocrystalline GdPO₄:Eu³⁺ was prepared by co-precipitation method with EDTA-2Na.The results of XRDindicated that nanocrystalline GdPO₄:Eu³⁺ with the monoclinic monazite type was synthesized at 700 ℃,the XRDintensities of the samples increased with increasing of annealing temperature due to much better crystallization.By applying the Scherrer formula to the full width at half maximum of the(200) diffraction peak,the mean particle sizes could be calculated as 18 nm and 40 nm,for the samples annealed at 700 ℃ and 800 ℃,respectively.The TEM images of the samples show the primary crystal size to be in consistent with the mean particle size obtained from XRD.The excitation spectrum of GdPO₄:Eu³⁺consist of several bands.The bands in the region from 200 nm to 300 nm may be due to the charge transfer band,the other bands from 300 nm to 500 nm are assigned to the Absorption band of Gd³⁺ and Eu³⁺ ions.The results of emission spectra exhibit all of emission peaks associated with ⁵D₀→⁷F_J transition,the relative intensity order of the emission is I(⁵D₀→⁷F₁)>I(⁵D₀→⁷F₂)>I(⁵D₀→⁷F₄),the emission intensities of the samples are increased with increasing of annealing temperature due to much better crystallization,a little broad emission peaks in smaller nanoparticles are mainly from the lattice distortion. The emission spectra under 315 nm excitation display that energy transfer exist between Gd³⁺ and Eu³⁺ ions effectively.