NaYF₄:Ln³⁺, due to its outstanding upconversion characteristics, has become one of the most important luminescent nanomaterials in biological imaging, optical information storage, and anticounterfeiting applications. However, the large specific surface area of NaYF₄:Ln³⁺ nanoparticles generally leads to serious nonradiative transitions, which may greatly hinder the discovery of new optical functionality with promising applications. In this paper, we report that monodispersed nanoscale NaYF₄:Ln³⁺, unexpectedly, can also be an excellent persistent luminescent (PersL) material. The NaYF₄:Ln³⁺ nanoparticles with surface-passivated core–shell structures exhibit intense X-ray-charged PersL and narrow-band emissions tunable from 480 to 1060 nm. A mechanism for PersL in NaYF₄:Ln³⁺ is proposed by means of thermoluminescence measurements and host-referred binding energy (HRBE) scheme, which suggests that some lanthanide ions (such as Tb) may also act as effective electron traps to achieve intense PersL. The uniform and spherical NaYF₄:Ln³⁺ nanoparticles are dispersible in solvents, thus enabling many applications that are not accessible for traditional PersL phosphors. A new 3-dimensional (2 dimensions of planar space and 1 dimension of wavelength) optical information-storage application is demonstrated by inkjet-printing multicolor PersL nanoparticles. The multicolor persistent luminescence, as an emerging and promising emissive mode in NaYF₄:Ln³⁺, will provide great opportunities for nanomaterials to be applied to a wider range of fields.

NaYF ₄ :Ln ³⁺由于其突出的上转换特性，已成为生物成像、光学信息存储和防伪应用中最重要的发光纳米材料之一。然而，NaYF ₄ :Ln ³⁺纳米粒子的大比表面积通常会导致严重的非辐射跃迁，这可能会极大地阻碍具有前景应用的新光学功能的发现。在本文中，我们报道了单分散的纳米级 NaYF ₄ :Ln ³⁺出人意料地也可以是一种出色的持久发光 (PersL) 材料。NaYF ₄ :Ln ³⁺具有表面钝化核壳结构的纳米粒子表现出强烈的 X 射线带电 PersL 和可从 480 到 1060 nm 可调的窄带发射。通过热释光测量和宿主参考结合能 (HRBE) 方案提出了NaYF ₄ :Ln ³⁺中 PersL 的机制，这表明一些镧系元素离子（如 Tb）也可以作为有效的电子陷阱来实现强珀斯 均匀球形 NaYF ₄ :Ln ³⁺纳米粒子可分散在溶剂中，从而实现传统 PersL 荧光粉无法实现的许多应用。喷墨打印多色 PersL 纳米粒子展示了一种新的 3 维（平面空间的 2 维和波长的 1 维）光学信息存储应用。多色持久发光作为NaYF ₄ :Ln ^{3+ 中}一种新兴且有前景的发光模式，将为纳米材料应用于更广泛的领域提供巨大的机会。