摘要
采用高温固相法合成Sr_(1.98)(Al_(1–x) Mg_x)(Al_(1–x) Si_(1+x))O_7: 2%Eu^(2+)荧光粉完全固溶体,利用X射线衍射、光致发光光谱和光学显微镜进行晶体结构和发光性能的研究. Sr_2Al_2SiO_7和Sr_2MgSi_2O_7同构化合物中包含[MgO_4]、[SiO_4]和[AlO_4]四面体,较大体积的[MgO_4]和较小体积的[SiO_4],共同替代体积相似的[AlO_4],导致[(Si/Al)O_4]收缩和[(Mg/Al)O_4]膨胀,晶胞参数c减少, a和V增大,使Eu^(2+)周围的环境发生改变,晶体场劈裂程度减小,发射峰位从503 nm蓝移至467 nm,实现发光光谱从绿色(0.2384, 0.3919)到蓝色(0.1342,0.1673)的转变.当x为0时,发射峰的半高宽为120 nm, x从0.25增加到1时,半高宽由89 nm逐渐减小至50 nm,多面体的替代会改变荧光粉的发光性能.
A series of Sr1.98(Al1–x Mgx)(Al1–x Si1+x)O7:2%Eu2+phosphors is prepared by the high-temperature solid-state reaction method,the crystal structures and luminescent properties of the prepared phosphors are investigated by measuring the X-ray diffraction,luminescent spectra and optical microscope.The isomorphic compounds of Sr2 Al2 SiO7 and Sr2 MgSi2 O7 contain tetrahedra including[MgO4],[SiO4]and(AlO4)Although the valences of the[MgO4]6–,[SiO4]4–and[AlO4]5–groups are different,the charge imbalance occurs when the[MgO4]6–and[SiO4]4–substitutes of[AlO4]5–and[AlO4]5–,respectively.While the groups are co-substituted,the charge imbalance disappears.And the larger volume of[MgO4]and the smaller volume of[SiO4]together replaces the similar volume of[AlO4],resulting in the decrease of[(Si/Al)O4]and increase of((Mg/Al)O4)Moreover,the decrease of unit cell parameters c and the increase of a and V due to the increased replacement of Mg2+(0.57?for CN=4)by Al3+(0.39?for CN=4)and Si4+(0.26?for CN=4)by Al3+(0.39?for CN=4)cause the ambient temperature to change,the crystal field splitting of the Eu2+cation to be weakened,and the emission spectra to be blue-shifted from 503 nm to 467 nm,which are closely related to the local coordination environment of the Eu2+,in addition,this reveals that the emission color of this series of phosphors can be tuned from green with color coordinate(0.2384,0.3919)to blue(0.1342,0.1673)by adjusting the chemical compositions via the[MgO4]6–and[SiO4]4–groups’co-substitution for[AlO4]5–.The full width at half maximumof emission band is120 nm when x=0,the photoluminescence emission width decreases monotonically from 89 to 50 nm as x is increased from 0.25 to 1.In other words,the full width at half maximum of emission band exhibits a decreasing trend.The internal quantum efficiency is enhanced with increasing x in Sr1.98(Al1–x Mgx)(Al1–x Si1+x)O7:2%Eu2+phosphors.These results verify that the groups’substitutions are enhanced with polyhedron changing in the solid solutions
作者
王庆玲
迪拉热.哈力木拉提
沈玉玲
艾尔肯.斯地克
Wang Qing-Ling;Dilare·Halimulati;Shen Yu-Ling;Aierken·Sidike(Key Laboratory of Mineral Luminescent Material and Microstructure of Xinjiang,Xinjiang Normal University,Urumqi 830054,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第10期40-46,共7页
Acta Physica Sinica
基金
国家自然科学自然基金(批准号:11464045)资助的课题~~
