摘要
为了在激光防伪领域提高上转换材料的发射强度,采用高温固相法制备Al^(3+)、Ba^(2+)掺杂YF_3∶Er^(3+),Yb^(3+)材料。Al^(3+)、Ba^(2+)都会引起主晶格收缩现象,降低稀土离子周围局部晶体场对称性,增大4f^N内跃迁几率。由980 nm激发的上转换发射光谱可知,Al^(3+)掺杂摩尔分数为1.7%时,548 nm绿光和660 nm红光发射强度分别是不含Al^(3+)样品的1.1倍和1.4倍;Ba^(2+)掺杂摩尔分数为0.8%时,绿光和红光强度分别是不含Ba^(2+)样品的2.8倍和2.2倍。并通过X射线衍射(XRD)探讨Ba^(2+)含量对晶相的作用。通过差热分析(DTA)、发射光谱、XRD、扫描电子显微镜(SEM),对于最佳掺杂比例样品,烧结温度为955℃时发光性能、结晶度、晶粒生长较好。通过荧光寿命曲线以及上转换发射强度与激发电流的拟合结果,探讨548 nm绿光和660 nm红光的发光机理,并阐述980 nm激发YF_3∶Er^(3+),Yb^(3+)材料的能级跃迁过程。
Upconversion materials of YF3∶Er^3+,Yb^3+doped with Al^3+,Ba^2+were prepared by high temperature solid state method in order to enhance emission intensities in the field of laser anti-counterfeit.Al^3+and Ba^2+could cause host lattice shrinking,reduce local crystal field symmetry around rare earth ions,increasing the intra 4f N transition probabilities.The 548 nm green and 660 nm red emission intensities of samples doped with 1.7%Al^3+(mole fraction)were 1.1 and 1.4 times as strong as the ones without Al^3+respectively according to upconversion emission spectra under 980 nm excitation.The green and red emission intensities of samples doped with 0.8%Ba^2+(mole fraction)were 2.8 and 2.2 times as strong as the ones without Ba 2+respectively.The Ba^2+contents had effects on crystal phases with X-ray diffraction(XRD).The results of differential thermal analysis(DTA),emission spectra,XRD,scanning electron microscope(SEM)showed that optimal sintering temperature was 955℃where optimal luminescence properties,crystallinities,grain growth appeared for samples with the optimal doping contents.Luminescence mechanisms of 548 nm green and 660 nm red emissions were discussed with fluorescent lifetime curves and fitting results of upconversion emission intensity and excitation current.Energy level transition processes were represented for YF3∶Er^3+,Yb^3+materials under 980 nm excitation.
作者
张磊
范亚蕾
黄月霞
王德强
ZHANG Lei;FAN Ya-lei;HUANG Yue-xia;WANG De-qiang(School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China)
出处
《发光学报》
EI
CAS
CSCD
北大核心
2018年第11期1533-1541,共9页
Chinese Journal of Luminescence
