Ligand-assisted crystal engineering yielding high luminescence in lead-free Cs2ZrCl6 across length scales toward X-ray detection and imaging

Lead-free metal halide scintillators that combine high luminescence efficiency and good processability are highly desirable for X-ray detection and imaging. Here, we establish a room-temperature ultrasonic ligand-assisted strategy for crystal engineering of Cs 2 ZrCl 6 across distinct length scales. Oleic acid (OA) directs the formation of defect-suppressed microcrystals, affording an average photoluminescence quantum yield (PLQY) of 93.14%. Introducing oleylamine (OLA) together with the accompanying changes in the reaction environment yields nanocrystals while preserving an average PLQY of 83.62%. The microcrystals deliver intense radioluminescence, high X-ray sensitivity, and a low dose-rate detection limit of 78.4 nGy s −1 , while the nanocrystals enable flexible PDMS-based scintillation films with a spatial resolution of 4.1 lp mm −1 . This work identifies ligand-assisted size and surface control as an effective route to reconcile scintillation performance with processability in lead-free Cs 2 ZrCl 6 .