Ultra Stable X‐Ray Imaging Through a Mutually Reinforcing Strategy Between Perovskite Nanocrystal‐Polymethyltrifluoropropylsiloxane

Abstract The instability of halide perovskite nanocrystals (PNCs) and related composite polymer films posed considerable challenges for application in flexible optoelectronic devices. Herein, perovskite nanocrystal‐polymethyltrifluoropropylsiloxane (PNCs‐PMFS) composites are developed that exhibit outstanding optical stability and irradiation resistance through a mutually reinforcing strategy. The photoluminescence (PL) intensity of PNCs‐PMFS remained stable after four heating cycles, whereas perovskite nanocrystal‐polydimethylsiloxane (PNCs‐PDMS) composites exhibited a 31% decrease in PL intensity. Moreover, PNCs‐PMFS demonstrated superior luminescence stability under UV and X‐ray irradiation due to strong ion‐dipole interactions between PNCs and trifluoromethyl (CF 3 ) dipoles. Under γ‐ray irradiation (300 kGy), PNCs‐PMFS retained 73% (2.86 MPa) of the initial mechanical strength, while PMFS without PNCs retained only 51%. This enhancement is attributed to the effective reduction of free radical concentration in the system by PNCs, as confirmed by electron spin resonance (ESR) and curing curve. Density‐functional theory (DFT) calculations further indicated that PNCs adsorbed free radicals, thereby facilitating interfacial charge transfer and forming a stable resonance structure. These advancements enabled PNCs‐PMFS to serve as scintillation screens for X‐ray detection and imaging, achieving a spatial resolution of 19.0 lp mm −1 and a detection limit of 3.78 µGy s −1 , offering novel insights for designing of X‐ray detectors in high‐energy radiation environments.