Ueda Kazushige, Shimizu Yuhei, Nagamizu Kouta, Matsuo Masashi, Honma Tetsuo
Department of Materials Science, Graduate School of Engineering, Kyushu Institute of Technology , 1-1 Sensui, Tobata, Kitakyushu 804-8550, Japan.
Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayou-cho, Sayou-gun, Hyogo 679-5198, Japan.
Inorg Chem. 2017 Oct 16;56(20):12625-12630. doi: 10.1021/acs.inorgchem.7b02165. Epub 2017 Oct 3.
The difference in Tb green luminescence intensities in doped perovskite(ABO)-type alkaline earth stannates, AeSnO (Ae = Ca, Sr, Ba), and the Mg codoping effect on the luminescence intensities in doped CaMO (M = Sn, Zr) were investigated utilizing the X-ray absorption fine structures (XAFS) of the Tb L absorption edge. It is considered that the local symmetry at A sites is responsible for the different Tb luminescence intensities in AeSnO (Ae = Ca, Sr, Ba) doped with Tb ions at A sites. However, it was found from the XAFS spectra that some Tb ions are unintentionally stabilized at B sites as Tb, especially in BaSnO. Not only the central symmetry for Tb at A sites but also the presence of Tb at B sites were considered to bring about the absence of Tb luminescence in doped cubic BaSnO. No obvious changes in the Tb local structure at A sites were detected between Tb single doped and Tb-Mg codoped CaMO (M = Sn, Zr) from the extended XAFS oscillation, but the trace of Tb at B sites in the Tb single doped sample was observed in the X-ray absorption near edge structures. It is, therefore, considered that the Tb luminescence enhancement by Mg codoping is primarily attributed to the charge compensation rather than the changes in the local structure around Tb at A sites.
利用Tb L吸收边的X射线吸收精细结构（XAFS）研究了掺杂钙钛矿（ABO）型碱土锡酸盐AeSnO（Ae = Ca、Sr、Ba）中Tb绿色发光强度的差异，以及Mg共掺杂对掺杂CaMO（M = Sn、Zr）中发光强度的影响。认为A位的局部对称性是导致A位掺杂Tb离子的AeSnO（Ae = Ca、Sr、Ba）中Tb发光强度不同的原因。然而，从XAFS光谱发现，一些Tb离子会意外地以Tb³⁺形式稳定在B位，尤其是在BaSnO中。A位Tb的中心对称性以及B位存在Tb³⁺都被认为是导致掺杂立方BaSnO中Tb发光缺失的原因。从扩展XAFS振荡中未检测到Tb单掺杂和Tb-Mg共掺杂CaMO（M = Sn、Zr）中A位Tb局部结构有明显变化，但在X射线吸收近边结构中观察到了Tb单掺杂样品中B位的Tb³⁺痕迹。因此，认为Mg共掺杂导致的Tb发光增强主要归因于电荷补偿，而非A位Tb周围局部结构的变化。
