Abstract Metal doping has been an efficient method to enhance upconversion (UC) luminescence, however, the relationship between fluorescence kinetics and site occupation of luminescence center has barely been revealed. To solve this issue, we have designed a tri-doping system of various Ba2+ doped Tm3+/Yb3+:LiNbO3 to investigate the energy transfer (ET) rate and the site occupation quantitatively, where 4.8 and 7.9 folds enhancement of blue and red emission has been achieved, respectively. Owing to the sensitive 4f-4f transition between lanthanide ions, the ion environment could be presented vividly by the zigzag-shaped UC intensity variation for different Ba2+ doping concentrations. Then, the corresponding ET rate equations are established by steady-state rate equations which draw the site occupation process of lanthanide ions simultaneously. The calculated results for Foster ET rate, local optical power density, and pump power absorption illustrate that Ba2+ could adjust the ET rate by transforming the site of lanthanide ions in crystal lattice. More importantly, this method could shed light on the mechanism of UC enhancement by modulating ET rate via ion doping.

中文翻译：

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Ba2+三掺杂不同位点占用Tm3+/Yb3+:LiNbO3的上转换光谱探讨能量转移机制

摘要 金属掺杂一直是增强上转换（UC）发光的有效方法，然而，荧光动力学与发光中心位点占据之间的关系却鲜为人知。为了解决这个问题，我们设计了各种 Ba2+ 掺杂的 Tm3+/Yb3+:LiNbO3 的三掺杂系统来定量研究能量转移 (ET) 率和位点占用，其中蓝色和红色发射增强了 4.8 和 7.9 倍。分别达到。由于镧系离子之间敏感的4f-4f跃迁，不同Ba2+掺杂浓度下的锯齿形UC强度变化可以生动地呈现离子环境。然后，通过稳态速率方程建立相应的ET速率方程，同时绘制镧系元素离子的占位过程。Foster ET 速率、局部光功率密度和泵浦功率吸收的计算结果表明 Ba2+ 可以通过改变晶格中镧系元素离子的位置来调节 ET 速率。更重要的是，该方法可以通过离子掺杂调节 ET 速率来阐明 UC 增强的机制。