In this work, the mixed system composed of Zn2GeO4: Mn and MgGeO3: Mn, Eu was synthesized by the high temperature solid phase method. Under the external excitation, visual color of samples was yellow. However, after the excitation was completed, visual color turned to be red. From luminescence spectrum, it was found that Zn2GeO4: Mn emitted green fluorescence of 534 nm under the excitation of 375 nm light. At the same time, MgGeO3: Mn, Eu emitted both fluorescence and persistent luminescence (PersL) of 668 nm. Moreover, the properties of PersL present samples were superior to other red PersL materials. Fine band structures from density functional theory (DFT) indicated that there were different luminescent mechanisms of Zn2GeO4: Mn and MgGeO3: Mn, Eu. When Zn2GeO4: Mn was excited, electron transitioned from VB to CB directly. Through CB, the electron was captured by the4T2(D) of Mn ion, then the electron jumped from4T2(D) to VB and recombined at once with the previous hole and emitted a 534 nm photon. When MgGeO3: Mn, Eu was excited, electron transitioned from6A1(S) of Mn ion to CB and left a hole. Through CB, electron was captured by7F6levels of Eu[Formula: see text] and remained metastable for a long time, which slowed down the recombined rate between electron and hole. Under thermal stimulation, the captured electron returned to CB from7F6levels and was recaptured by the4T2(D) of Mn. The electron transitioned down toward6A1(S) and recombined with the hole immediately, then emitted a photon with 668 nm.

中文翻译：

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MgGeO3:Mn、Eu和Zn2GeO4:Mn混合体系发光机理及不同视觉颜色的实验与理论研究

在这项工作中，由 Zn 组成的混合体系2氧化锗4: Mn 和 MgGeO3：Mn、Eu通过高温固相法合成。在外部激发下，样品的视觉颜色为黄色。然而，激发完成后，视觉颜色变为红色。从发光光谱中发现，Zn2氧化锗4: Mn 在 375 nm 光的激发下发出 534 nm 的绿色荧光。同时，MgGeO3：Mn、Eu 发出 668 nm 的荧光和持久发光 (PersL)。此外，PersL 现有样品的性能优于其他红色 PersL 材料。来自密度泛函理论 (DFT) 的精细能带结构表明 Zn 存在不同的发光机制2氧化锗4: Mn 和 MgGeO3: 锰，欧盟。当锌2氧化锗4：Mn被激发，电子直接从VB跃迁到CB。通过 CB，电子被4吨2(D) Mn 离子，然后电子从4吨2(D) 到 VB 并立即与前一个孔重新组合并发射 534 nm 光子。当 MgGeO3：Mn，Eu被激发，电子从6一种1(S) Mn 离子对CB 并留下一个空穴。通过 CB，电子被7F6Eu[公式：见正文]的水平，并长时间保持亚稳态，这减慢了电子与空穴之间的复合速率。在热刺激下，捕获的电子从7F6水平，并被重新夺回4吨2（四）锰。电子向下跃迁6一种1(S) 并立即与空穴重新结合，然后发射一个 668 nm 的光子。