(La,Ce,Tb)BO3的合成及光谱性质

采用高温固相法合成了(La,Ce,Tb)BO₃绿色发光粉,并对该发光粉进行了XRD和SEM分析。结果表明:(La,Ce,Tb)BO₃的晶体结构和LaBO₃相同,Ce³⁺、Tb³⁺的掺入并没有改变晶体的结构,发光粉颗粒大小均匀,形貌规则,粒度在5 μm左右。研究了(La,Ce,Tb)BO₃的光谱性质,在(La,Ce,Tb)BO₃的发射和激发光谱中除了有Tb³⁺的特征发射和激发峰外,还有Ce³⁺的特征发射和激发峰。比较了(La,Ce)BO₃发射光谱和(La,Tb)BO₃的激发光谱,两者存在重叠,这为Ce³⁺→Tb³⁺的能量传递提供了条件。将(La,Ce,Tb)BO₃的发射光谱与商品粉(La,Ce,Tb)PO₄进行比较,两者的发射主峰都在541 nm处, (La,Ce,Tb)BO₃在489 nm处的峰位稍有红移,通过计算表明,(La,Ce,Tb)BO₃的发光亮度达到商品粉(La,Ce,Tb)PO₄的94.7%。因此,(La,Ce,Tb)BO₃是一种很有应用前景的绿色发光粉。

Synthesis and Luminescence Properties of (La,Ce,Tb)BO3 Phosphors

The phosphor of (La,Ce,Tb)BO_3 was synthesized by high temperature solid state reaction. X-ray diffraction(XRD) patterns indicated that (La,Ce,Tb)BO_3 and LaBO_3 have the same crystal structure, the crystal structure was not changed by doping with Ce~(3+) and Tb~(3+) . Emission scanning electron microscopy (SEM) image showed that the phosphor particles is uniform, the morphology is regular, and the granularity is about 5 μm. The luminescence properties of (La,Ce,Tb)BO_3 phosphor were studied, both the Tb~(3+) characteristic emission and excitation peaks and the Ce~(3+) characteristic emission and excitation peaks were observed in the emission and excitation spectrum of (La,Ce,Tb)BO_3. The emission spectra of Ce~(3+) in (La,Ce)BO_3 and the excitation spectra of Tb~(3+) in (La,Tb)BO_3 have large superposition at 330～400 nm regions, which supply good conditions for energy transfer from Ce~(3+) to Tb~(3+). The energy transfer between Ce~(3+) and Tb~(3+) is primarily as resonance transfer. Both of (La,Ce,Tb)BO_3 phosphor and commercial phosphor (La,Ce,Tb)-PO_4 have main emission peak at 541 nm. Comparing (La,Ce,Tb)BO_3 phosphor with commercial phosphor (La,Ce,Tb)BO_3, (La,Ce,Tb)BO_3 phosphor has a little red shift at 489 nm and its relative emission intensity was 94.7% of the commereial phosphor (La,Ce,Tb)PO_4. Therefore, it is expected that (La,Ce,Tb)BO_3 phosphor would be a promising green-emitting phosphors.