Ultrabright Thermally Boosted Ln‐MOF X‐Ray Scintillators: A Multifunctional Platform for Upconversion Luminescence and Lipid Droplet Imaging

ABSTRACT The sharp decline in light yield ( LY ) of X‐ray scintillators under extreme high temperatures remains a key bottleneck for their application in high‐temperature radiation imaging. Herein, 1,2,4,5‐tetra(4‐carboxyphenyl)benzene (H 4 TCPB) are employed as linkers to assemble lanthanide cluster {Eu 4 O 30 } secondary building units, affording ultrabright thermally enhanced Eu‐TCPB‐MOF based X‐ray scintillators. Specifically, the luminescence intensity of the X‐ray excited luminescence (XEL) spectrum of the Eu‑TCPB‑MOF based X‐ray scintillator in the range of 300–440 K continues to increase with increasing temperature, and the peak luminescence intensity is 1.96 times the room temperature value. It shows that the material has excellent scintillation properties under high temperature conditions. This improvement stems from reduced nonradiative energy loss caused by O–H vibration, after coordinated terminal water desorbs from the framework at high temperatures. Eu‐TCPB‐MOF also retains excellent radiation stability and high‐resolution scintillation imaging performance. Furthermore, the isostructural Eu‐TCPB‐MOFs platform integrates multiple functionalities: two‐photon upconversion luminescence and lipid droplet‐targeted live‐cell optical imaging. This work opens new avenues for designing thermally enhanced ultrabright Ln‐MOF scintillators and establishes a versatile platform for multifunctional Ln‐MOFs applications.