Mn^(2+)掺杂对YAG∶Ce^(3+)荧光陶瓷发光性能的影响

Comparative Study of Mn^(2+)on Luminescence Properties in YAG∶Ce^(3+)Phosphor Ceramics

过渡族金属Mn^(2+)掺杂的石榴石荧光陶瓷被认为是实现高显色激光照明的候选材料。然而,由于Mn^(2+)在不同配位环境下离子半径的多样性,Mn^(2+)掺杂石榴石陶瓷体系设计方案尚不明确。本文采用真空烧结技术制备得到不同浓度Mn^(2+)掺杂的YAG∶Ce^(3+)荧光陶瓷,并将Mn^(2+)分别设计进入八面体(OC)和十二面体(DO)格位。通过表征样品物相和显微结构、光致发光、荧光寿命、量子效率等,并通过LD激光器激发对荧光陶瓷的发光性能进行研究。实验结果表明,在添加电荷与体积补偿剂SiO_(2)的前提下,相比Mn^(2+)进入十二面体格位,Mn^(2+)进入八面体后石榴石的晶体结构更加稳定。因此,当Mn^(2+)的浓度控制在0.5%^(6)%(at)范围内,OC系列样品的量子效率高于DO系列样品。此外,OC系列样品的PL谱中位于588 nm和725 nm处的发射峰分别对应于Mn^(2+)占据八面体和十二面体格位的^(4)T_(1)→^(6)A_(1)电子跃迁,而DO系列样品中位于572 nm处的发射峰则源于Mn^(2+)占据扭曲的十二面体格位产生的电子跃迁。得益于Ce^(3+)→Mn^(2+)间高效的能量传递,将浓度为6%(at)的Mn^(2+)设计进入YAG∶Ce^(3+)中八面体格位制得荧光陶瓷,封装得到的激光白光光源的显色指数为70.8,相对色温为5117 K。本文对于Mn^(2+)掺杂的石榴石发光材料的开发研究是有力补充,也为提升YAG∶Ce^(3+)荧光陶瓷光谱中的红光成分,进而提高医疗、显示等领域的激光光源的显色性能提供借鉴。

Transition-metal Mn^(2+)ion doped garnet phosphor ceramics are promising for laser lighting with high color rendering.However,the scheme for Mn^(2+)doped garnet ceramics is still ambiguous due to the diversity of ionic radii of Mn^(2+)in different coordinate environment.In this study,two series of YAG∶Ce^(3+)phosphor ceramics with different Mn^(2+)concentrations occupying octahedral(OC)and dodecahedral(DO)lattice sites were fabricated by vacuum sintering.The crystal structure,photoluminescence,fluorescence decay curves,quantum efficiency and electro-luminescence properties were studied in detail.The garnet crystal structure with Mn^(2+)occupying in octahedral(OC)sites was more stable under the premise of doping SiO_(2) as charge and volume compensator.Therefore,the quantum efficiency of the OC series samples was higher than that of the DO series,in case the Mn^(2+)concentration fixed at 0.5%−6%(at).In addition,emission bands of OC series samples peaked at 588 nm and 725 nm,were corresponding to the ^(4)T_(1)→^(6)A_(1) transitions of Mn^(2+)located at octahedral,and dodecahedral sites,respectively.The emission peak at 572 nm in the DO series was assigned to the transition of Mn^(2+)occupying in distorted dodecahedral sites.Benefiting from the efficient energy transfer from Ce^(3+)to Mn^(2+),the CRI and CCT of 70.8 and 5117 K,respectively,were acquired from the white LD lighting device structured by YAG∶Ce^(3+)phosphor ceramics with 6%(at)Mn^(2+)occupying in octahedral site.This study presents a strong supplement to the research on Mn-doped garnet luminescent materials,and provides a reference for improving the color rendering performance of laser lighting sources by adding the red spectral component of YAG∶Ce^(3+)phosphor ceramics,further driving their application in the field of medical treatment and display.