一种新型可协调绿色荧光材料BaAl2Si2O8∶Tb3+,Ce3+的发光性质与能量传递

摘要

采用高温固相法制备了BaAl2Si2O8∶Tb3+,Ce3+系列的荧光材料,讨论了Tb3+,Ce3+单掺及Tb3+,Ce3+共掺样品的光谱性质及发光机理,分析了Ce3+与Tb3+之间的能量传递过程.通过对样品进行XRD,荧光光谱,色坐标等测试.结果表明,Tb3+,Ce3+的掺杂没有改变BaAl2Si2O8晶体的结构.BaAl2Si2O8∶Tb3+发出明亮的绿光,发光峰分别位于487,545,583和621 nm对应于Tb3+的5D4→7FJ(J=6,5,4,3)特征发射.Ce3+的掺入没有改变BaAl2Si2O8∶Tb3+发射光谱的位置,但使其激发谱由窄带激发变成了宽带激发增加了谱带多样性,发光强度有了明显的增强,而且颜色也具有一定的协调性,使其在实际运用方面具有更大的灵活性.发光强度增强的原因不仅仅是因为Ce3+的敏化作用,还与Ce3+和Tb3+之间存在能量传递有密切关系.通过猝灭法计算了,Ce3+与Tb3+之间的能量传递的临界距离为15.345 nm,并且证明了能量传递是由偶极-偶极相互作用产生的.通过计算得到能量传递效率最高达到了76.04%.%The blue phosphors designed as BaAl2Si2O8∶Tb3+,Ce3+ were prepared with high temperature solid-state reaction.The luminescence properties and mechanism of Tb3+,Ce3+,Tb3+ and Ce3+ Co-doped samples were discussed.Energy transfer between Ce3+ and Tb3+ in the sample was analyzed.The samples were tested with XRD,fluorescence spectra,color coordinates and so on.The results have shown that a small number of Tb3+,Ce3+ ions doping fail to change the crystal structure of BaAl2Si2O8.BaAl2Si2O8∶Tb3+ shows bright green.Emission spectra are the narrow-band spectral lines composed by peak-to-peak value of 487,545,583 and 621 nm,which are the typical emission peak generated due to 5D→7FJ(J=6,5,4,3) transition of Tb3+ ions.The incorporation of Ce3+ not only makes the excitation spectra of BaAl2Si2O8∶Tb3+ from the narrow band excitation to broadband excitation increases the spectral band diversity.The luminous intensity has obvious enhancement,and the color also has some coordination,which makes it more flexible in practical application.The reason for the enhancement of luminescence intensity is not only because of the sensitization of Ce3+ ions,but also due to the energy transfer between Tb3+ and Ce3+.The critical distance of energy transfer has been calculated with the concentration quenching method,which is 153.45 nm.The energy transfer mechanism is ascribed to the dipole-dipole interaction.When the Tb3+ion concentration was increased to 0.07 the transfer efficiency increased to 76.04%.