In this study, Bi3+ incorporation in NaYbF4 :Er lattice and its influence on upconversion luminescence properties have been investigated in detail using techniques such as temperature-dependent luminescence, Fourier transform infrared spectroscopy and X-ray diffraction (XRD). The study was carried out to develop phosphors with improved upconversion luminescence. From photoluminescence and lifetime measurements it is inferred that luminescence intensity from NaYbF4 :Er increases with Bi3+ addition. The sample containing 50 at.% Bi3+ ions exhibited optimum upconversion luminescence. Increased distance between Yb3+ -Yb3+ and Er3+ -Er3+ due to Bi3+ incorporation into the lattice and associated decrease in the extent of dipolar interaction/self-quenching are responsible for increase in lifetime values and luminescence intensities from Er3+ ions. Incorporation of Bi3+ into NaYbF4 :Er lattice reduced self-quenching among Yb3+ -Yb3+ ions and this facilitated energy transfer from Yb3+ to Er3+ . This situation also explains decrease in the extent of temperature-assisted quenching of emission from thermally coupled 2 H11/2 and 4 S3/2 levels of Er3+ . Based on Rietveld refinement of XRD patterns it was confirmed that a maximum of 10 at.% of Bi3+ added was incorporated into the NaYbF4 :Er lattice and the remaining complex co-exists as a BiOF phase. These results are of significant interest in the area of development of phosphors based on Yb3+ -Er3+ upconversion luminescence.

中文翻译：

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Bi3 +添加对NaYbF4：Er上转换发光性能的影响。

在这项研究中，已使用诸如温度依赖性发光，傅立叶变换红外光谱和X射线衍射（XRD）等技术详细研究了Bi3 +在NaYbF4：Er晶格中的掺入及其对上转换发光性能的影响。进行了研究以开发具有改善的上转换发光的磷光体。从光致发光和寿命测量可以推断出，NaYbF4：Er的发光强度随Bi3 +的添加而增加。包含50 at。％Bi3 +离子的样品表现出最佳的上转换发光。由于Bi3 +掺入晶格中，Yb3 + -Yb3 +和Er3 + -Er3 +之间的距离增加以及偶极相互作用/自猝灭程度的相关降低导致寿命值的增加和Er3 +离子的发光强度增加。将Bi3 +掺入NaYbF4：Er晶格可减少Yb3 + -Yb3 +离子之间的自猝灭，从而促进了从Yb3 +到Er3 +的能量转移。这种情况还解释了热辅助2 H11 / 2和4 S3 / 2能级Er3 +的发射的温度辅助猝灭程度的降低。根据X射线衍射图的Rietveld精炼，已确认最多将10 at。％的Bi3 +添加到NaYbF4：Er晶格中，其余的复合物以BiOF相共存。这些结果在基于Yb3 + -Er3 +上转换发光的荧光粉的开发领域中具有重大意义。这种情况还解释了热辅助2 H11 / 2和4 S3 / 2能级Er3 +的发射的温度辅助猝灭程度的降低。根据X射线衍射图的Rietveld精炼，已确认最多将10 at。％的Bi3 +添加到NaYbF4：Er晶格中，其余的复合物以BiOF相共存。这些结果在基于Yb3 + -Er3 +上转换发光的荧光粉的开发领域中具有重大意义。这种情况还解释了热辅助2 H11 / 2和4 S3 / 2能级Er3 +的发射的温度辅助猝灭程度的降低。根据X射线衍射图的Rietveld精炼，已确认最多将10 at。％的Bi3 +添加到NaYbF4：Er晶格中，其余的复合物以BiOF相共存。这些结果在基于Yb3 + -Er3 +上转换发光的荧光粉的开发领域中具有重大意义。