All-inorganic Mn 2+ -doped metal halide perovskite crystals for the late-time detection of X-ray afterglow imaging.

All-inorganic metal halide perovskite (MHP) materials have been widely studied because of their unique optoelectronic properties, whereas there has been little research reported on their X-ray afterglow imaging properties. Herein, we report the design and synthesis of Mn 2+ -doped hexagonal CsCdCl 3 MHP crystals with excellent X-ray scintillation and X-ray induced afterglow. The orange emission from Mn 2+ shows a red shift due to the strong interaction of the Mn 2+ -Mn 2+ dimers formed at higher doping concentrations. The high-energy X-rays with higher electron filling capacity to feed the shallow (0.71 eV) and deep (0.90-1.08 eV) traps enable a long orange afterglow for more than 300 min. The afterglow emission can be rejuvenated effectively by 870 nm stimulus or heating even after 72 h of decay. Finally, we demonstrate the proof-of-concept applications of the fabricated flexible scintillator films for real-time online X-ray imaging with a spatial resolution of 12.2 lp mm -1 , as well as time-lapse X-ray imaging recorded by a cell phone, which shows promise for being able to do offline late-time detection of X-ray afterglow imaging in the future.