High‐Performance Flexible X‐ray Scintillators Based on Manganese Halides With Near‐Unity Quantum Yield

ABSTRACT 0D manganese‐based X‐ray scintillators have garnered significant attention due to their unique ion‐centered luminescence and high photoluminescence quantum yields (PLQYs). However, achieving a synergistic optimization among light yield, detection limit, spatial resolution, and non‐planar imaging capability remains a challenge. In this study, single crystals of (C 25 H 22 P) 2 MnBr 4 are synthesized via a solvent evaporation method. Owing to the tetrahedral coordination geometry of the [MnBr 4 ] 2− polyhedron and the characteristics of the d‐d electron transition of Mn 2+ , the as‐prepared materials exhibit a strong green emission at 512 nm with a high PLQY of 91.27%. Furthermore, flexible (C 25 H 22 P) 2 MnBr 4 @PDMS scintillators are fabricated via a template assembly method. Benefiting from high optical transparency and excellent luminescent properties, the scintillators demonstrate outstanding radiative performance, achieving a maximum light yield of up to 48750 ph/MeV, a low detection limit of 45.8 nGy air /s, and a high spatial resolution of 17.64 lp/mm. Notably, the flexible scintillators are capable of realizing both planar and non‐planar X‐ray imaging with high quality, thereby offering a versatile and effective platform for high‐performance X‐ray visualization.