Bi 3+ /Ln 3+ Co‐Doped Cs 2 SnCl 6 Double Perovskites: Promising Scintillators for High‐Performance X‐Ray Imaging Screens

Considering the growing demand for X‐ray imaging technologies in nondestructive inspection and medical radiography, the development of novel scintillator materials featuring superb stability, nontoxicity, high light yield, and low detection limit becomes imperative. Herein, we synthesize the high‐performance Bi 3+ /Ln 3+ (Ln = ═Yb, Er, Yb/Er) co‐doped Cs 2 SnCl 6 scintillators through a facile solvothermal method. Owing to the high photoluminescent quantum yield (PLQY ≈ 89.5%), large Stokes shift (580 nm), and strong X‐ray attenuation, the Cs 2 SnCl 6 :1%Bi 3+ /0.5%Yb 3+ /0.5%Er 3+ scintillator exhibits a light yield as high as 72 800 photons MeV −1 , and a detection limit as low as 149.6 nGy air /s. Benefiting from their outstanding scintillation performance and robust stability, PMMA‐combined imaging screens realize high‐resolution target structural imaging. This work shows great promise for advancing high‐quality X‐ray imaging and paves the way for more precise imaging in relevant fields.