Highly pure red phosphors LiM(PO):Eu (M = Sr, Ca) doped with Eu (1 mol%) were synthesized via solution combustion method and their crystal structure and luminescence dynamics were studied to explore its suitability in white light emitting diodes. The Rietveld refinement analysis of the powder X-ray diffraction patterns reveals that the phosphors belong to the pure triclinic phase of LiSr(PO) and LiCa(PO) with space group - (2). The scanning electron microscopy images showed the agglomerated morphology. The photoluminescence emission spectra under 393 nm show an orange band at 594 nm and a red band at 613 nm ascribed to D → F, D → F transitions of Eu ion in both the phosphors. Moreover, the spectroscopic properties such as luminescence behaviour, and Stark splitting were used to examine the symmetry of Eu ions in LiM(PO):Eu (M = Sr, Ca) phosphors in terms of distortion induced upon doping. The Stark splitting shows that the actual site symmetry for Eu ion was estimated to be D type for both phosphors The photometric properties of LiCa(PO):Eu such as Commission International de l’Eclairage coordinates ( = 0.64, = 0.36) near to the standard one (red), high color purity (95%) and higher brightness reveal that the phosphor has the capability of acting as a red component in n-UV white light emitting diodes.

中文翻译：

---

白光发光二极管用高纯LiM(PO3)3:Eu3+ (M = Sr, Ca)红色荧光粉的晶体结构和发光动力学


采用溶液燃烧法合成了掺杂Eu (1 mol%)的高纯红色荧光粉LiM(PO):Eu (M = Sr, Ca)，并研究了其晶体结构和发光动力学，以探索其在白光发光二极管中的适用性。粉末X射线衍射图的Rietveld细化分析表明，荧光粉属于空间群为-(2)的LiSr(PO)和LiCa(PO)的纯三斜晶相。扫描电子显微镜图像显示了团聚形态。 393 nm 下的光致发光发射光谱在 594 nm 处显示橙色带，在 613 nm 处显示红色带，这归因于两种荧光粉中 Eu 离子的 D → F、D → F 跃迁。此外，利用发光行为和斯塔克分裂等光谱特性来检查 LiM(PO):Eu (M = Sr, Ca) 荧光粉中 Eu 离子在掺杂时引起的畸变的对称性。 Stark 分裂表明，两种荧光粉的 Eu 离子的实际位点对称性估计为 D 型 LiCa(PO):Eu 的光度特性，如国际照明委员会坐标 ( = 0.64, = 0.36) 接近标准一（红色）、高色纯度（95%）和更高的亮度表明该荧光粉具有在n-UV白光发光二极管中充当红色成分的能力。