共沉淀法制备暖白光LED用Na2TiF6:Mn4+红色荧光粉及其发光性能研究

采用简便的共沉淀法制备了不同Mn⁴⁺ 掺杂摩尔分数的Na₂TiF₆:Mn⁴⁺ 红色荧光粉。通过X射线衍射仪、扫描电子显微镜、红外光谱仪、荧光光谱仪对荧光粉的结构、形貌、傅立叶红外光谱、激发和发射光谱及荧光寿命曲线进行了表征。结果表明,Mn⁴⁺的掺杂没有改变Na₂TiF₆的晶格结构,样品具有六方结构。Mn⁴⁺最佳掺杂摩尔分数为4.77%,量子效率为74%。在460 nm激发下,最强窄带发射峰位于628 nm处(²E_g-⁴A₂),色坐标为(0.681,0.317)。²E_g能级的荧光寿命曲线遵循双指数衰减,其荧光寿命值为3.148 ms。

Co-precipitation Synthesis and Luminescence Properties of Na2TiF6:Mn4+ Red Phosphors for Warm White Light Emitting Diodes

Na₂TiF₆:Mn⁴⁺ red phosphors with different Mn⁴⁺ doping mole fraction were synthesized by the co-precipitation method. Structure, morphology, photoluminescence excitation and emission spectra as well as decay curve of Na₂TiF₆:Mn⁴⁺ phosphors were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectrometer. As-prepared Na₂TiF₆:Mn⁴⁺ phosphors have hexagonal structures. Under 460 nm excitation, intense red emissions corresponding to ²E_g-⁴A₂ transitions of Mn⁴⁺ are observed. The optimum doping mole fraction of Mn⁴⁺ is 4.77% and the quantum efficiency is 74% for this phosphor. The chromaticity coordinates of the Na₂TiF₆:Mn⁴⁺ phosphors are (0.681, 0.317). Decay curve of ²E_g state for as-prepared Na₂TiF₆:Mn⁴⁺ sample fits the second order exponential behavior, and the average lifetime is 3.148 ms.