固体中过渡金属离子占位、价态及光谱性质的第一性原理研究  

First-principles Calculations on Site Occupancy,Valence State and Luminescent Properties of Transition Metal Activators in Solids

作　　者：陈巧玲 景伟国 尚龙兵 段昌奎[1,2] 尹民[2] CHEN Qiaoling;JING Weiguo;SHANG Longbing;DUAN Changkui;YIN Min(CAS Key Laboratory of Microscale Magnetic Resonance,University of Science and Technology of China,Hefei 230026,China;Department of Physics,School of Physical Sciences,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学技术大学中国科学院微观磁共振实验室,安徽合肥230026 [2]中国科学技术大学物理学院物理系,安徽合肥230026

出　　处：《发光学报》2023年第7期1220-1238,共19页Chinese Journal of Luminescence

基　　金：国家自然科学基金(11974338)。

摘　　要：过渡金属(TM)激活离子由于在近红外发光、红外激光、荧光转化的白光LED、荧光温度计、余辉发光等方面的优异性能和应用潜力而被广泛研究。TM离子在固体中可占据八配位、六配位、四配位等多种配位格位,可呈现多种价态且光跃迁性质强烈依赖于晶体环境,因此TM离子在固体中的发光中心确定、发光机理理解和性能预测存在困难。本文通过第一性原理计算探索固体中TM离子的热力学和光跃迁性质。内容包括:通过对各种化学氛围下形成能的计算结果,分析基质的本征缺陷以及TM离子占位、价态、分布和浓度;理解不同晶体环境中TM离子的各激发态和能级结构;构建位形坐标图分析激发、弛豫、发射及猝灭过程;提出通过合成氛围、共存条件和离子共掺等方式调控或优化TM离子的占位、价态和光跃迁的方案。本文以若干具有代表性的体系为依托,展示了如何运用第一性原理计算手段进行掺TM离子固体发光材料的研究。具体所涉及的代表体系和研究内容为:Ti:Al_(2)O_(3)激光晶体中红外残余吸收机理及其减弱或尽可能消除的方法,典型尖晶石和石榴石基质中Mn^(2+)、Mn^(3+)、Mn^(4+)的占位和激发、弛豫、发射等光跃迁性质,固溶氧化物基质中铬离子的占位、价态及相应的光跃迁性质等,表明第一性原理计算可用于发光材料的机理研究、理性设计和优化。Transition metal(TM)activators have been widely studied for their extraordinary optoelectronic proper⁃ties and great potential application in near-infrared luminescence or persistent luminescence,infrared laser,phos⁃phor-converted white light-emitting diodes,luminescence thermometry and so on.However,due to the multiple va⁃lence states and multiple site occupancies,and the strongly local-environment-dependent optical properties,it is challenging to determine the sites and valences of the luminescent center,to decipher the luminescent mechanisms and to predict the photoluminescence properties of TM activators in solids.Here,first-principles calculations have been performed to study the thermodynamic and optical properties of TM ions in solids.The defect formation energies are calculated to analyze the effects of intrinsic defects and the site occupancies,valence states,distribution and con⁃centration of TM ions in host.The local environment dependent luminescence is analyzed by calculating the excitedstate energy levels of TM activators in various lattice environment.The configuration coordinate diagrams are con⁃structed to analyze the excitation,relaxation and emission processes.Then,a theoretical scheme is proposed to regulate the site-occupancy,valence states and optical transitions of TM ions in solids via tuning the sintering atmosphere,co⁃existence conditions,and especially co-doping impurities.We select several typical systems to show the rationality and effectiveness of first-principles calculations,which include the mechanisms of residual infrared absorption in Ti∶Al_(2)O_(3) crystal and the method of mitigating or eliminating the infrared absorption,the site occupancies and optical transitions of Mn^(2+),Mn^(3+),Mn^(4+)in typical spinel and garnet hosts,the site occupancies,valence states and optical transitions of Cr^(3+)/^(4+)ions in oxide compounds.The results show that first-principles calculations form effective ap⁃proaches for elucidating the multi-site and multi-valence nature of T

关 键 词：过渡金属离子 光跃迁 第一性原理计算 

分 类 号：O482.31[理学—固体物理]