In this work, a novel germanate-based orange-emitting long persistent luminescent (PersL) phosphor, K₄CaGe₃O₉(KCGO):Mn²⁺,Yb³⁺, has been successfully synthesized via a solid-state reaction. The special nanostructures of KCGO:Mn²⁺ and KCGO:Mn²⁺,Yb³⁺ were indicated by transmission electron microscope (TEM) images, where the block particles of these samples are shown to consist of many irregular spherical nanoparticles and the size of these spherical particles is less than 10 nm. This special nanostructure contains many defects and could provide the preconditions for the PersL properties of KCGO:Mn²⁺. Furthermore, after co-doping with Yb³⁺, the PersL properties are effectively improved due to the high concentration of new traps caused by the non-equivalent substitution of Yb³⁺. With the optimum doping concentration and sufficient excitation with UV light, the afterglow of KCGO:0.02Mn²⁺,0.015Yb³⁺ can persist over 5 h above the recognizable intensity level (≧0.32 mcd m⁻²). Both the fluorescence and phosphorescence spectra of KCGO:Mn²⁺,Yb³⁺ exhibit only one broad emission band, which belongs to the ⁴T₁(G)–⁶A₁(S) transition of Mn²⁺. In addition, with the help of thermoluminescence (TL) curves, the processes and possible mechanism are studied and discussed.

中文翻译：

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K ₄ CaGe ₃ O ₉：Mn 2 ⁺，Yb ³⁺：具有特殊纳米结构的新型橙色发光长持续发光磷光体

在这项工作中，通过固相反应成功地合成了一种新型的基于锗酸盐的橙色发光的持久发光（PersL）荧光粉K ₄ CaGe ₃ O ₉（KCGO）：Mn 2 ⁺，Yb ³⁺。透射电子显微镜（TEM）图像显示了KCGO：Mn ²⁺和KCGO：Mn 2 ⁺，Yb ³⁺的特殊纳米结构，其中这些样品的块状颗粒由许多不规则球形纳米颗粒组成，其大小为这些球形颗粒小于10nm。这种特殊的纳米结构包含许多缺陷，可以为KCGO：Mn的PersL特性提供前提条件。²⁺。此外，在与Yb ³⁺共掺杂之后，由于由Yb ³⁺的非等价取代引起的新陷阱的高浓度，有效地改善了PersL特性。在最佳掺杂浓度和足够的紫外光激发下，KCGO：0.02Mn 2 ⁺，0.015Yb ³⁺的余辉可以在可识别的强度水平（≥0.32mcdm ^-2）之上持续5 h。KCGO：Mn 2 ⁺，Yb ³⁺的荧光和磷光光谱均仅显示一个宽的发射带，属于锰的⁴ T ₁（G）– ⁶ A ₁（S）跃迁²⁺。另外，借助热致发光（TL）曲线，研究和讨论了过程和可能的机理。