Liu Yijia, Zhang Gengxin, Huang Junben, Tao Xiaoma, Li Guihua, Cai Gemei
School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan, People's Republic of China.
Key Lab of Non-Ferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, Hunan, People's Republic of China.
Inorg Chem. 2021 Feb 15;60(4):2279-2293. doi: 10.1021/acs.inorgchem.0c03121. Epub 2021 Jan 29.
Single-phase white-emission phosphors possess a judicious usage potential in phosphor-converted white-light-emitting diodes (WLEDs). Recently, numerous efforts have been made toward the development of new patterns of white-emitting phosphors that achieve excellent quantum yield, superior thermal stability, and applaudable cost effectiveness of WLEDs. Finding suitable single-component white phosphor hosts to provide an ideal local environment for activators remains urgent. Inspired by the original discovery of the promising host MgIn(PO) (MIP) and its structural dependence on alkali-metal cations, we synthesized a brand-new phosphor host, SrIn(PO) (SIP), via the traditional solid-state reaction. Its crystal structure was determined using an ab initio analysis and the Rietveld method. It belongs to a monoclinic unit cell with the space group 2/. Besides, SIP exhibits a special layered three-dimensional framework in which the monolayer [SrO] was surrounded by a bilayer [InPO] made of the InO octahedra and PO groups. A series of pure SIP:Tm,Dy phosphors with tunable blue-white-yellow emission were prepared by adjusting the dopant concentration and utilizing the Tm-Dy energy transfer. The daylight-white-emitting phosphor SIP:0.01Tm,0.04Dy (the correlated color temperature is 4448 K) exhibits an abnormal thermal antiquenching property, and the emission intensity of 423 K reaches 103.7% of the initial value at 300 K. On the basis of the temperature-dependent lattice evolution and microenvironment analysis, the reduction of β and lattice distortion can lead to lower asymmetry of the activators and benefit the compensation of trapped-electron thermal activation. In this work, an integration study was carried out on the crystal structure of the new matrix, the occupation of the luminescent center, the interaction of different activators in the host, and the distortion degree of the local structure for the activators, which is of great practical sense for producing a novel single-matrix white phosphor possessing superior thermal endurance for UV-light-stimulated WLEDs.
单相白色发射荧光粉在荧光粉转换白光发光二极管（WLED）中具有明智的应用潜力。最近，人们为开发新型白色发射荧光粉做出了许多努力，这些荧光粉要实现优异的量子产率、卓越的热稳定性以及WLED令人称赞的成本效益。寻找合适的单组分白色荧光粉基质以为激活剂提供理想的局部环境仍然十分迫切。受有前景的基质MgIn(PO)（MIP）的最初发现及其对碱金属阳离子的结构依赖性启发，我们通过传统的固态反应合成了一种全新的荧光粉基质SrIn(PO)（SIP）。其晶体结构通过从头算分析和Rietveld方法确定。它属于单斜晶胞，空间群为2/。此外，SIP呈现出一种特殊的层状三维框架，其中单层[SrO]被由InO八面体和PO基团组成的双层[InPO]包围。通过调节掺杂剂浓度并利用Tm-Dy能量转移制备了一系列具有可调蓝-白-黄发射的纯SIP:Tm,Dy荧光粉。日光白色发射荧光粉SIP:0.01Tm,0.04Dy（相关色温为4448 K）表现出异常的热猝灭特性，在423 K时的发射强度达到300 K时初始值的103.7%。基于温度依赖性晶格演化和微环境分析，β的降低和晶格畸变可导致激活剂的不对称性降低，并有利于捕获电子热激活的补偿。在这项工作中，对新基质的晶体结构、发光中心的占据情况以及基质中不同激活剂之间的相互作用以及激活剂局部结构的畸变程度进行了综合研究，这对于生产具有优异热耐久性的用于紫外光激发WLED的新型单基质白色荧光粉具有重要的实际意义。
