Abstract In this work, the photoluminescence features, decay lifetime, internal quantum yield, and thermal stability of whitlockite structured phosphors of Ca9MgLi(PO4)7:Dy3+ were investigated. The phosphor exhibit the capability of being efficiently excited by near-UV (350, 364, 387 nm) and blue light (451 nm), exhibiting the characteristic greenish-yellow emission with two strong peaks at 487 and 577 nm, ascribing to the transitions of 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2, respectively. The phosphor synthesized using a conventional solid-state reaction method at 1350 °C also show high phase purity with good compositional homogeneity and crystallinity. The Ca9MgLi(PO4)7:0.1Dy3+ phosphor showed the optimal photoluminescence emission intensity and quantum yield. The electronic transition mechanism is direct exchange interaction between activators, contributing to the concentration quenching. The phosphor was able to retain 67% of its intensity without significant colour change at an elevated temperature up to 300 °C. This work illustrates the potential of Ca9MgLi(PO4)7:Dy3+ phosphors for the application in white LED devices pumped with an n-UV or blue-emitting chip.

中文翻译：

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黄绿色发光 Ca9MgLi(PO4)7:Dy3+ 磷光体 – 光致发光和热稳定性

摘要 在这项工作中，研究了Ca9MgLi(PO4)7:Dy3+ 白钙石结构荧光粉的光致发光特性、衰变寿命、内量子产率和热稳定性。荧光粉表现出被近紫外（350、364、387 nm）和蓝光（451 nm）有效激发的能力，表现出特有的黄绿色发射，在 487 和 577 nm 处有两个强峰，归因于跃迁分别为 4F9/2 → 6H15/2 和 4F9/2 → 6H13/2。在 1350 °C 下使用常规固态反应方法合成的荧光粉还显示出高相纯度、良好的成分均匀性和结晶度。Ca9MgLi(PO4)7:0.1Dy3+ 荧光粉显示出最佳的光致发光发射强度和量子产率。电子跃迁机制是活化剂之间的直接交换相互作用，有助于浓度猝灭。在高达 300 °C 的高温下，荧光粉能够保持其强度的 67%，而没有显着的颜色变化。这项工作说明了 Ca9MgLi(PO4)7:Dy3+ 磷光体在使用 n-UV 或蓝色发光芯片泵浦的白色 LED 设备中的应用潜力。