CaF PDMATHAAB/ SrF $_2$ /BaF PDMATHAAB：Yb $^{3+}$：Er $^{3+}$纳米粒子的吸收光谱、缺陷位分布和上转换激发光谱
Absorption Spectra, Defect Site Distribution and Upconversion Excitation Spectra of CaF$_2$/SrF$_2$/BaF$_2$:Yb$^{3+}$:Er$^{3+}$ Nanoparticles
摘要：
我们报告的Yb $^{3+}$网站分布在Er $^{3+}$共掺杂的上转换碱土金属氟化物纳米粒子使用高分辨率的吸收测量的研究。类似的散装晶体，Yb $^{3+}$单离子立方（O $_h$），并优先形成的集群是中等掺杂剂浓度的主导中心。在较高的浓度，并为较大的颗粒尺寸，少数C $_{4v}$（F $^-$）中心也被观察到。此外，Yb $^{3+}$团簇中心的行为，其主要吸收带位于10 205 cm $^{-1}$附近（与980 nm激光二极管的近共振），通过从Ca $^{2+}{\rightarrow}$ Sr $^{2+}{\rightarrow}$ Ba $^{2+}$调节基质晶格中的金属阳离子来研究。对于共掺杂的材料，异质集群中心，Er $^{3+}$上转换荧光观察到Yb $^{3+}$的选择性激发后，导致强可见光发射$^4$ H $_{11/2}$，$^4$ S $_{3/2}$和$^4$ F $_{9/2}$多重态。通过监测Er $^{3+}$ $^4$ S $_{3/2}{\rightarrow}^4$ I $_{15/2}$（540 nm）荧光，同时通过波长依赖性Yb 3+吸收扫描激光，我们获得这些异质簇中心的激发光谱。它表明，组的Yb $^{3+}$离子附近的Er $^{3+}$离子代表一个小的子集的整体Yb $^{3+}$合奏，因此线性吸收测量不一定是一个很好的指示的最佳激光泵浦波长。
英文摘要：
We report studies of the Yb$^{3+}$ site distribution in Er$^{3+}$ co-doped upconverting alkaline earth fluoride nanoparticles using high-resolution absorption measurements. Similar to bulk crystals, Yb$^{3+}$ single ion cubic (O$_h$), and preferentially formed clusters are the dominant centres for moderate dopant concentrations. At higher concentrations, and for larger particle sizes, a minority C$_{4v}$(F$^-$) centre is also observed. Furthermore, the behaviour of Yb$^{3+}$ cluster centres, whose primary absorption band is located around 10205 cm$^{-1}$ (in near resonance with 980 nm laser diodes) was studied by tuning the metal cation in the host lattice from Ca$^{2+}{\rightarrow}$Sr$^{2+}{\rightarrow}$Ba$^{2+}$. For co-doped materials, with heterogeneous cluster centres, Er$^{3+}$ upconversion fluorescence was observed upon selective excitation of Yb$^{3+}$, resulting in strong visible emission from $^4$H$_{11/2}$, $^4$S$_{3/2}$ and $^4$F$_{9/2}$ multiplets. By monitoring the Er$^{3+}$ $^4$S$_{3/2}{\rightarrow}^4$I$_{15/2}$ (540 nm) fluorescence, whilst scanning a laser through the wavelength dependent Yb3+ absorption, we obtain an excitation spectrum for these heterogeneous cluster centres. It is demonstrated that the group of Yb$^{3+}$ ions residing near an Er$^{3+}$ ion represent a small subset of the overall Yb$^{3+}$ ensemble and therefore a linear absorption measurement is not necessarily a good indication of the optimum laser pump wavelength.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
