论文标题
欧盟掺杂缺陷pyrochlore氧化物knbwo $ _6 \ cdot $ h $ _2 $ o：eu $^$^{3+} $
First-principles study on luminescence properties of Eu-doped defect pyrochlore oxide KNbWO$_6\cdot$H$_2$O:Eu$^{3+}$
论文作者
论文摘要
缺陷的pyrochlore氧化物由于其柔性成分和高电子/孔迁移率而引起了极大的发光材料的极大兴趣。在这项工作中，我们通过使用第一原则计算，研究了兰谷掺杂（LN）缺陷pyrochlore氧化物\ ce {KnBWO6} {3+} $的结构和电子特性。我们对各种缺陷的pyrochlore模型进行结构优化，并计算其电子结构，表明水合对欧盟$^{3+} $ ion周围的局部对称性和带状结构都有显着影响，并改变了其发光行为。在水合化合物中，发现电动偶极$^5 $ d $ _0-^7 $ f $ _2 $过渡被发现被当地升高的对称性所抑制，并且化合物中的水分子可以介导非辐射能量转移的非辐射能量转移，而激活剂Eu $^{3+} $ ions and The Host and Host and Quench均可介导。事实证明，氧气空位对发光有害，因为它们在其与Eu $^{2+} $ ion附近减少了欧盟$^{3+} $ ion，并且还可以充当因入射光而激发的传导电子的陷阱。我们计算\ ce {knbwo6}：0.125ln $^{3+} $（ln = ce，pr，nd，pm，sm）支持缺陷pyrochlore氧化物\ ce {knbwo6}也可以用作ln $^+prominent in a proviate in a lum portries in a lum interione to promention in a promention in thum intiment in thum intiment in thum intiment in thum from in在原子水平。
Defect pyrochlore oxides have attracted a great interest as promising luminescent materials due to their flexible composition and high electron/hole mobility. In this work, we investigate the structural and electronic properties of lanthanide-doped (Ln) defect pyrochlore oxides \ce{KNbWO6}:0.125Ln$^{3+}$ by using first-principles calculations. We perform structural optimizations of various defect pyrochlore models and calculate their electronic structures, revealing that hydration has a significant influence on both local symmetry around Eu$^{3+}$ ion and band structures with an alteration of their luminescent behaviour. In the hydrated compounds, the electric-dipole $^5$D$_0-^7$F$_2$ transition is found to be partially suppressed by the raised local symmetry, and the water molecules in the compounds can mediate the non-radiative energy transfer between the activator Eu$^{3+}$ ions and the host, resulting in the quenching effect. It turns out that the oxygen vacancies are detrimental to luminescence as they reduce the Eu$^{3+}$ ion in its vicinity to Eu$^{2+}$ ion and also serve as traps for conduction electrons excited by incident light. Our calculations for \ce{KNbWO6}:0.125Ln$^{3+}$ (Ln = Ce, Pr, Nd, Pm, Sm) support that defect pyrochlore oxide \ce{KNbWO6} can also be used as luminescence host for Ln$^{3+}$ ion doping, giving a valuable insight into a variation trend in luminescent properties of these materials at atomic level.
