KZnF3：Ce，Tb的溶剂热合成及光谱性质

Solvothermal Synthesis and Fluorescence of KZnF_3∶Ce,Tb

采用溶剂热法合成了Ce3+,Tb3+单掺和双掺KZnF3发光粉。分析了样品的结构与形貌。结果表明,所合成的样品均为单相,颗粒粒度分布均匀。讨论了它们的光谱特性。研究发现,在KZnF3∶Ce3+激发光谱中激发带劈裂成2个带峰,最大发光中心分别位于263 nm(主峰)和246 nm,而在发射光谱中只观察到1个带状发射峰,最大发射中心位于330 nm。在KZnF3∶Tb3+激发光谱中存在较强的基质激发峰,而在发射光谱中,发现Tb3+的5D4→7FJ(J=6,5,4,3)跃迁。在KZnF3双掺体系中,Tb3+的发光强度随Ce3+的浓度增加而增强,存在Ce3+→Tb3+能量传递,尤其是Tb3+的5D4→7F5跃迁发射显著增强,有望成为一种有发展前途的绿色荧光材料。

Abstract： Phosphors of KZnF3 ：Ce^3＋, KZnF3 ：Tb^3＋ and KZnF3 ：Ce^3＋,Tb^3＋ were synthesized respectively through solvothermal method at 220 ℃. X-ray diffraction （XRD） pattern was used to identify the formation of KZnF3 phase without detectable impurity. Environment scanning electron microscopy （ESEM） image showed the grain size distribution was uniform with cubic morphology. Spectral characteristics of the rare earth ions doped KZnF3 had been investigated. In Ce-doped KZnF3 system, there were two emission peaks in the excitation spectrum, locatedat 246 and 263 nm, respectively, while the emission spectrum of Ce-doped KZnF3 appeared as a broad range with the maximum center located at 330 nm. In Tb-doped KZnF3 system, there was strong matrix exciting peak in the excitation spectrum, while the transition from 5D4→^7TFJ （J=6, 5, 4, 3） of Tb^3＋ was found in the emission spectrum. The luminescence intensity of Tb^3＋ strengthened with the increase of the Ce^3＋ ion concentration in co-doped system of KZnF3. It was found that there was an effective energy transfer from Ce^3＋ to Tb^3＋ and especially the emission peaks ascribed to Tb^3＋ ions transition from 5D4→^7F5 strengthened greatly in KZnF3. It was expected that the phosphor of KZnF3：Ce^3＋, rib^3＋ would become a promising green-emitting fluorescent material.