CaLu2Al4SiO12:Eu3+荧光粉的制备和发光性能研究

Preparation and Luminescent Properties of CaLu2Al4SiO12：Eu3+ Phosphors

摘要:

现代农业如植物工厂的快速发展对植物照明的需求不断扩大，发光强度高、热稳定性良好的深红色荧光粉是LED人工植物照明光源的关键材料。为研究Eu³⁺在CaLu_2-xAl₄SiO₁₂基质中的发光性能，采用高温固相法合成了新型CaLu_2-xAl₄SiO₁₂:xEu³⁺（x=0.1、0.3、0.5、0.7、0.9、1.1）荧光粉，通过多种表征测试技术，系统地研究了荧光粉的晶体结构、微观形貌、荧光性质及热稳定性能，并初步探究了CaLu_2-xAl₄SiO₁₂:xEu³⁺在植物照明领域应用的可能性。通过XRD、Rietveld结构精修、EDS能谱和元素分布分析发现， Eu³⁺成功进入了CaLu₂Al₄SiO₁₂基质中。荧光光谱测试结果表明：在711 nm光的监测下，样品在280—500 nm范围出现了Eu³⁺的特征f-f跃迁吸收峰；在394 nm光的激发下，样品在550—750 nm范围出现了Eu³⁺的⁵D₀-⁷F_J （J=0、1、2、3、4）跃迁发射，其最强发射峰位于711 nm（⁵D₀-⁷F₄）处，Eu³⁺的最佳掺杂量x=0.5；Eu³⁺的荧光寿命衰减曲线和荧光发射光谱，证明了Eu³⁺在CaLu₂Al₄SiO₁₂基质中只占据一个晶体学格位；CaLu_1.5Al₄SiO₁₂:0.5Eu³⁺荧光粉在423 K下的发射峰积分强度为室温下的91.75%，表明了该荧光粉具有良好的热稳定性；CaLu_2-xAl₄SiO₁₂:xEu³⁺的深红色强发射峰位于711 nm处，与植物的光敏色素（P_FR）吸收波段相吻合，表明CaLu_2-xAl₄SiO₁₂:xEu³⁺是一种潜在的可用于LED植物照明的荧光粉。

Abstract:

The rapid development of modern agriculture such as plant factories has continuously expanded the demand for plant lighting. Crimson phosphors with high luminous intensity and good thermal stability are the key materials for LED artificial plant lighting sources. To study the luminescent properties of Eu³⁺ in CaLu₂Al₄SiO₁₂ host， a series of new type CaLu_2-xAl₄SiO₁₂：xEu³⁺ （x=0.1， 0.3， 0.5， 0.7， 0.9， 1.1） phosphors were synthesized by a high-temperature solid-state method. The crystal structure， morphology， luminescent properties， thermal stability were systematically studied， and the possibility of the application of CaLu₂Al₄SiO₁₂：Eu³⁺ phosphors in the field of plant lighting was preliminarily explored. Rietveld XRD refinement results， EDS and elemental mapping images indicated that Eu³⁺ has successfully entered the CaLu₂Al₄SiO₁₂ matrix. The excitation spectra of CaLu₂Al₄SiO₁₂：Eu³⁺ showed typical f-f transitions of Eu³⁺ monitoring at 711 nm light. Under the excitation of 394 nm light， CaLu_2-xAl₄SiO₁₂：xEu³⁺ gave rise to several sharp emission peaks at 580—750 nm range due to the ⁵D₀-⁷F_J （J=0， 1， 2， 3， 4） transitions of Eu³⁺， and the dominant emission peak centered around 711 nm. The optimal doping concentration of Eu³⁺ in CaLu₂Al₄SiO₁₂ is 0.5. The emission spectra and fluorescence decay curve indicated that the Eu³⁺ occupied only one crystallographic site in CaLu₂Al₄SiO₁₂. The emission intensity at 423 K is 91.75% of that at room temperature， which proved the excellent thermal stability of CaLu₂Al₄SiO₁₂：Eu³⁺. The deep red emission of CaLu₂Al₄SiO₁₂：Eu³⁺ at 711 nm matched well with the absorption spectra of phytochromes （P_FR）， indicating that CaLu₂Al₄SiO₁₂：Eu³⁺ is a promising red emitting phosphor for plant lighting LED application.