All-Inorganic Ruddlesden–Popper Perovskite Cs₂CdCl₄:Mn for Low-Dose and Flexible X-ray Imaging

We report a Mn 2+ -activated all-inorganic 2D layered Ruddlesden–Popper (RP) perovskite Cs 2 CdCl 4 single crystal as a highly efficient and stable X-ray scintillator. The Cs 2 CdCl 4:10% Mn achieves a bright orange-red emission with a photoluminescence quantum yield up to 90.47%, good environmental stability, and decent thermal quenching resistance. As a scintillator, Cs 2 CdCl 4:10% Mn shows strong X-ray absorption, ultrahigh light yield up to 88138 photons/MeV, and low detection limit of 31.04 nGy air /s. A 15 × 15 cm flexible scintillation screen is prepared by mixing poly(dimethylsiloxane) (PDMS) with Cs 2 CdCl 4:Mn powder, which demonstrates superior X-ray imaging performance with a high spatial resolution of 16.1 lp mm –1 at a modulation transfer function (MTF) = 0.2. Importantly, due to the ultrahigh X-ray sensitivity, the flexible scintillator screen achieved clear X-ray imaging at an extremely low dose of 16 μGy air /s. This successful exploitation of the 2D high light yield perovskite scintillator in flexible low-dose X-ray imaging would provide new insight into high-sensitivity X-ray detection.