Thermally Activated Delayed Fluorescence Zirconium‐Based Perovskites for Large‐Area and Ultraflexible X‐ray Scintillator Screens

Flexible scintillator screens with environmental stability, high sensitivity, and low cost have emerged as candidates for X-ray imaging applications. Here, a large-scale and cost-efficient solution synthesis of the vacancy-ordered double perovskite Cs2 ZrCl6 , which is characterized by thermal activation delayed fluorescence (TADF) dominated by triplet emission under X-ray irradiation, is demonstrated. The large Stokes shift and efficient luminescence collection of TADF effectively ensure the light outcoupling efficiency. Further, flexible X-ray scintillator screens with an area of 400 cm2 are prepared using poly(dimethylsiloxane) (PDMS) as the carrier, exhibiting excellent scintillation properties with light yields as high as 49 400 photons MeV-1 , spatial resolutions up to 18 lp mm-1 and detection limits as low as 65 nGy s-1 . Finally, the high-quality imaging results of non-planar and dynamic objects by such screens are demonstrated. It is believed that the explored Cs2 ZrCl6 @PDMS flexible scintillator screens would offer a big step toward expanding the application range of scintillators in different environments.