通过离子交换一步法合成了K2SiF6:xMn4+,yTi4+系列红色荧光粉,研究了Mn4+、Ti4+掺杂量对荧光粉结构及发光性能的影响。采用X射线衍射仪表征了荧光粉的晶体结构,发现少量Mn4+、Ti4+掺杂对荧光粉的空间结构未产生显著的影响,制备的红色荧光粉呈立方体面心结构。荧光光谱分析表明,位于353nm和455nm处的激发峰分别属于Mn4+(3d3)的 4A2→4T1和 4A2→4T2的电子跃迁。以波长455nm的蓝光作为激发光源,Mn4+掺杂量为1%(摩尔分数)的K2SiF6:1% Mn4+荧光粉在580～750nm范围内出现3个尖峰,分别位于616nm、634nm、650nm处,对应于Mn4+的 2Eg→4A2跃迁,Ti4+的掺杂使得荧光粉在634nm处的发射强度提高了7倍左右。当温度上升至420K时,K2SiF6:1% Mn4+荧光粉在634nm处的发射强度仅仅降至室温时的65.8%,表现出优良的热稳定性。
K2SiF6:Mn4+ red phosphors co-doped with Ti4+ were synthesized using ion exchange method.X-ray power diffraction,temperature-dependent luminescence,and photoluminescence analysis were used for characterizing the phosphors.The phosphors doped with various concentrations of Mn4+ and Ti4+ had identical well-formed face center cubic of K2SiF6.For phosphors of K2SiF6:1% Mn4+,excitation peaks located at 353nm and 455nm correspond to electron transition of 4A2→4T1 and 4A2→4T2,respectively.The peaks showed in the emission spectra(616nm,634nm,650nm) belong to the 2Eg→4A2 transition of Mn4+.Otherwise,the doping of Ti4+ in phosphors resulted in the maximum luminous intensity of phosphors at peak of 634nm increasing by about 7 times,comparing to the K2SiF6:1% Mn4+ phosphors.At the temperature of 420K,the emission intensity of K2SiF6:1% Mn4+ fell to 65.8% compared to that at room temperature,showing good thermal stability.
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