Abstract Owning to exceptional optical and physicochemical properties, lanthanide-doped inorganic dual-mode luminescence materials are regarded as promising platform for multifunctional applications. Herein, a facile hydrothermal method is used to integrate Ce3+ and Nd3+ ions co-doped NaLuF4 phosphors, achieving dual-mode with ultraviolet (UV) and the second near-infrared (NIR-II) luminescence from single particles under two excitation sources. Higher NaF/LnCl3 ratio can not only promote the crystal phase transformation from cubic to hexagonal and the shape evolution from nanoparticles to microprisms, but also promote the UV and NIR-II luminescence properties of NaLuF4:Ce3+, Nd3+ phosphors. Upon irradiation with X-ray, Ce3+ and Nd3+ ions co-doped NaLuF4 phosphors exhibit strong broad band UV emission due to 5d → 4f transition emission of Ce3+. Under 808 nm NIR excitation, the phosphors give NIR-II emission with two peaks at around 1060 nm and 1340 nm, which are attributed to the 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 electron transitions of Nd3+ ions respectively. Furthermore, the possible emission and energy transfer mechanism between Ce3+ and Nd3+ under the excitation of X-ray and 808 nm laser are discussed in details. The above results not only pave the way for future research of dual-mode luminescent materials, but also endow such materials with potential bio-applications for deep tissue bioimaging and therapy.

中文翻译：

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来自 Ce3+、Nd3+ 共掺杂 NaLuF4 荧光粉的 NIR-II 发光和 X 射线诱导的紫外发光

摘要 镧系元素掺杂无机双模发光材料具有优异的光学和物理化学性质，被认为是多功能应用的有前途的平台。在此，采用简便的水热法集成 Ce3+ 和 Nd3+ 离子共掺杂的 NaLuF4 荧光粉，在两个激发源下从单个粒子实现紫外 (UV) 和第二近红外 (NIR-II) 发光的双模式。较高的 NaF/LnCl3 比不仅可以促进晶体从立方体到六方体的相变和从纳米颗粒到微棱柱的形状演变，而且可以促进 NaLuF4:Ce3+、Nd3+ 荧光粉的 UV 和 NIR-II 发光性能。在 X 射线照射下，Ce3+ 和 Nd3+ 离子共掺杂的 NaLuF4 荧光粉由于 Ce3+ 的 5d → 4f 跃迁发射而表现出强的宽带紫外发射。在 808 nm NIR 激发下，荧光粉发出 NIR-II 发射，在 1060 nm 和 1340 nm 附近有两个峰值，这分别归因于 Nd3+ 离子的 4F3/2 → 4I11/2 和 4F3/2 → 4I13/2 电子跃迁. 此外，详细讨论了在X射线和808 nm激光激发下Ce3+和Nd3+之间可能的发射和能量转移机制。上述结果不仅为双模发光材料的未来研究铺平了道路，而且赋予了此类材料在深层组织生物成像和治疗方面的潜在生物应用。详细讨论了X射线和808 nm激光激发下Ce3+和Nd3+之间可能的发射和能量转移机制。上述结果不仅为双模发光材料的未来研究铺平了道路，而且赋予了此类材料在深层组织生物成像和治疗方面的潜在生物应用。详细讨论了X射线和808 nm激光激发下Ce3+和Nd3+之间可能的发射和能量转移机制。上述结果不仅为双模发光材料的未来研究铺平了道路，而且赋予了此类材料在深层组织生物成像和治疗方面的潜在生物应用。