Paradigm Enhancement of White‐Light Responsive NIR‐II Photoluminescence via Toroidal Energy Migration

Abstract Near‐infrared II (NIR‐II, 1000–1700 nm) lanthanide‐doped fluorescent probes provide a powerful new tool for existing clinical biomedical sensing and imaging. However, it is impeded in practical applications by its specific high‐energy laser source. Herein, a white‐light responsive Ce³⁺‐mediated toroidal energy migration downshifting topological core–shell structure NIR‐IIb (1500–1700 nm) fluorescent probe is reported. It is found that Ce³⁺ doping enhances the NIR downshifting luminescence of the Ho³⁺ and Nd³⁺, thereby increasing the energy‐transferred Yb³⁺ luminescence. The NaCeF₄ core is able to further facilitate the crossrelaxation between the intermediate‐shell layer of Er³⁺ and Ce³⁺ through the outward‐to‐inward core–shell topology, enhancing the 1527 nm luminescence to form the toroidal energy migration paradigm. Additionally, the luminescence of Er³⁺ exhibits strong temperature dependence, enabling superior temperature sensing under multiple light sources. Under low‐power white light source, the relative sensitivity (S_r) can reach up to 0.57% K⁻¹, with a minimum temperature uncertainty (δT) of 0.2 K. Moreover, portable light conversion using highly efficient white‐light responsive emission in NIR‐II region enables noninjectable intravenous imaging and food inspection. This toroidal energy migration strategy provides a new direction for lanthanide energy harvesting and multisource NIR applications.