Thermodynamic Stabilities, Electronic Properties, and Optical Transitions of Intrinsic Defects and Lanthanide Ions (Ce3+, Eu2+, and Eu3+) in Li2SrSiO4
Thermodynamic Stabilities, Electronic Properties, and Optical Transitions of Intrinsic Defects and Lanthanide Ions (Ce3+, Eu2+, and Eu3+) in Li2SrSiO4
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Li2SrSiO4 中本征缺陷和镧系离子（Ce3、Eu2 和 Eu3）的热力学稳定性、电子性质和光学跃迁
DOI：
10.1021/acs.inorgchem.8b00752
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发表时间：
2018
影响因子：
4.6
通讯作者：
Yin Min
中科院分区：
文献类型：
--
作者：
Wen Jun;Gu Zhidong;Guo Hai;Ning Lixin;Duan Chang Kui;Huang Yucheng;Zhan Shengbao;Yin Min
通过理论计算，结合混合密度泛函理论、多参考组态相互作用方法和经验模型，研究了Li 2SrSiO 4（LSSO）基质中本征缺陷（空位和反位缺陷）和镧系离子（Ce 3+、Eu 2+和Eu 3+）的几何结构、电子性质、热力学稳定性和光学跃迁。通过对Ce ~（3+）离子的缺陷形成能的计算和4f → 5d电子跃迁的从头算模拟，确定了LSSO：Ce ~（3+）荧光粉最可能的电荷补偿机制，并准确识别了实验光谱中的激发带。基于先前报道的Ce 3+和Eu 3+掺杂的LSSO磷光体的实验光谱以及Dorenbos开发的一系列经验模型，在基质中Ln 3+和Ln 2+离子的4f基态和最低5d激发态的位置（由基质参考结合能方案说明，即，HRBE方案），这对研究镧系元素掺杂的LSSO的电子转移和光谱性质是有用的。此外，热力学和光学跃迁能级相关的本征缺陷和镧系离子（具有各种电荷状态）来自总能量计算。对LSSO：Eu ~（2+），Dy ~（3+）荧光粉的热释光（TL）和长余辉（LLL）发光机理，特别是氧空位（VO）和Dy ~（3+）掺杂的贡献进行了解释。因此，本研究的目的是从理论计算和分析中深入理解镧系元素掺杂荧光粉的电荷补偿、TL和LLL机制。
Geometric structures, electronic properties, thermodynamic stabilities, and optical transitions of intrinsic defects (vacancies and antisite defects) and lanthanide ions (Ce3+, Eu2+, and Eu3+) in Li2SrSiO4(LSSO) host are studied by theoretical calculations combined with hybrid density functional theory, the multireference configuration interaction method, and empirical models. Calculations on the defect formation energies and the ab initio simulations of 4f → 5d electronic transitions for Ce3+ions determine the most possible charge-compensation mechanism and accurately identify excitation bands in experimental spectra for LSSO:Ce3+phosphors. On the basis of previously reported experimental spectra of Ce3+- and Eu3+-doped LSSO phosphors as well as a series of empirical models developed by Dorenbos, the locations of the 4f ground states and the lowest 5d excited states of Ln3+and Ln2+ions in the host (illustrated by the host-referred binding energy scheme, i.e., the HRBE scheme) are obtained, which is useful for the investigation of the electron-transfer and spectroscopic properties in lanthanide-doped LSSO. Moreover, thermodynamic and optical transition energy levels related to intrinsic defects and lanthanide ions (with various charge states) are derived from total energy calculations. The mechanisms of thermoluminescence (TL) and long-lasting luminescence (LLL) in LSSO:Eu2+,Dy3+phosphors and especially the contributions of oxygen vacancies (VO) and Dy3+dopants are then interpreted. The aim of this study is thus to deeply understand the mechanisms of charge compensation, TL, and LLL in lanthanide-doped phosphors from theoretical calculations and analyses.