The demand for near-infrared (700–1,700 nm) materials in optical communications, laser sources and biological imaging applications has led to extensive research on lanthanide-doped nanoparticles, owing to their nanostructure modulation and interface property tunability. However, the low molar extinction coefficient of conventional lanthanide sensitizers limits the brightness of lanthanide near-infrared nanoparticles for applications in low-power excitation scenarios. Here we introduce Na₃CrF₆, a new crystalline nanoparticle that serves as both sensitizer and host for high-brightness near-infrared emission from lanthanide activators (Er³⁺, Tm³⁺, Yb³⁺ or Nd³⁺). We demonstrate an increase in brightness of up to 370 times compared with the most intense conventional lanthanide-sensitized nanoparticles. This discovery is also validated for other lanthanide-doped nanoparticles sensitized with low-cost transition metals (Mn²⁺ or Ni²⁺). Our transition metal-based nanoparticles represent a powerful toolbox to enable high signal-to-noise-ratio labelling and imaging with low-power excitation sources such as white light-emitting diode or persistent luminescence materials. This work paves the way for next-generation high-brightness near-infrared luminescence systems, suited for a wide range of low-illumination excitation applications.

光通信、激光源和生物成像应用对近红外（700-1,700 nm）材料的需求导致了对稀土掺杂纳米粒子的广泛研究，因为它们具有纳米结构调制和界面性质可调性。然而，传统稀土敏化剂的低摩尔消光系数限制了稀土近红外纳米粒子在低功率激发场景中的应用的亮度。在这里，我们介绍了Na ₃ CrF ₆ ，一种新型晶体纳米粒子，它既可作为敏化剂，又可作为镧系元素激活剂（Er ³⁺ 、Tm ³⁺ 、Yb ³⁺或Nd ³⁺ ）高亮度近红外发射的主体。我们证明，与强度最高的传统镧系元素敏化纳米粒子相比，亮度提高了高达 370 倍。这一发现也适用于其他低成本过渡金属（Mn ²⁺或 Ni ²⁺ ）敏化的镧系元素掺杂纳米粒子。我们的过渡金属纳米粒子代表了一个强大的工具箱，可以使用低功率激发源（例如白色发光二极管或持久发光材料）进行高信噪比标记和成像。这项工作为下一代高亮度近红外发光系统铺平了道路，适用于各种低照度激发应用。