Herein, a series of Mn-activated ZnGa₂O₄ (ZGO) phosphors have been developed for multifunctional applications. The characteristic green and red emission at 503 and 668 nm of Mn-activated ZGO phosphors can be observed under excitation of 247 and 375 nm, respectively, attributed to the partial oxidation of Mn²⁺ ions resulting in the coexistence of Mn²⁺ and Mn⁴⁺ ions in the host lattice. The valence modulation of Mn content not only realizes the adjustment of red and green luminescence intensity but also achieves the management of persistent luminescence time and thermo-luminescence time. Further, the codoping of Mg²⁺ could transform the position occupancy preference of Mn and effectively facilitate the conversion of Mn²⁺ to Mn⁴⁺, leading to the regulation of the valence state of manganese ions. Surprisingly, the existence of Mg²⁺ ions broadens the emission band of Mn⁴⁺ and enhances the photoluminescence intensity to 3.8 times, which can be ascribed to the weakened crystal field leading to the downward shift of the ⁴T₂ energy level and the increase of Mn⁴⁺ concentration. For this valence modulation behavior, two different hypotheses about the occupancy of Mg²⁺ have been proposed to explain the corresponding phenomenon. Finally, the potential applications of the synthesized phosphors have been explored in advanced anticounterfeiting strategies, information storage, and plant lighting field.

中文翻译：

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阳离子占据工程实现锰激活ZnGa2O4的价态调控


在此，我们开发了一系列用于多功能应用的锰激活 ZnGa ₂ O ₄ (ZGO) 荧光粉。 Mn激活ZGO荧光粉在247 nm和375 nm激发下分别在503 nm和668 nm处观察到特征绿光和红光发射，这归因于Mn ²⁺ 离子的部分氧化导致共存主晶格中的 Mn ²⁺ 和 Mn ⁴⁺ 离子。 Mn含量的价态调控不仅实现了红、绿发光强度的调节，还实现了持久发光时间和热发光时间的管理。此外，Mg ²⁺ 的共掺杂可以改变 Mn 的位置占据偏好，有效促进 Mn ²⁺ 向 Mn ⁴⁺ 的转化，从而调节锰离子的价态。令人惊讶的是，Mg ²⁺ 离子的存在拓宽了 Mn ⁴⁺ 的发射带，并将光致发光强度增强至 3.8 倍，这可以归因于晶体场减弱导致向下移动 ⁴ T ₂ 能级和 Mn ⁴⁺ 浓度的增加。对于这种价态调制行为，人们提出了两种关于 Mg ²⁺ 占据的不同假设来解释相应的现象。最后，探索了合成荧光粉在先进防伪策略、信息存储和植物照明领域的潜在应用。