In Situ Synthesis of Sb-Based Films with Multistate STE Emission for High-Resolution Curved X-ray Imaging

Lead-free, low-toxicity antimony (Sb)-based metal halides are promising scintillators due to their significant Stokes shift and high photoluminescence quantum yield (PLQY). However, their luminescence mechanism remains poorly understood. Conventional fabrication techniques of flexible scintillation screens introduce light scattering, degrading imaging quality, and their comparative performance in flexible versus rigid X-ray imaging remains largely unexplored. A large-area flexible (C 19 H 18 P) 2 SbCl 5 @PVDF (C 19 H 18 P + = Methyl triphenylphosphine, PVDF = Poly(vinylidene fluoride)) film is developed through the in situ annealing crystallization method, achieving a PLQY of 91.81% and a Stokes shift of 252 nm, thereby minimizing self-absorption. The plausible luminescence mechanism of (C 19 H 18 P) 2 SbCl 5 is identified as multistate self-trapped exciton emission under different excitation wavelengths or energies, as evidenced by femtosecond transient absorption spectroscopy and temperature-dependent photoluminescence studies. Both the single crystal and the film exhibit high light yields (37654 and 33505 photons MeV –1 ), good linear response, and strong irradiation resistance. The film’s flexibility and high spatial resolution of 22.6 line pairs mm –1 enable high-quality X-ray imaging on curved surfaces, significantly reducing vignetting effects. This work advances Sb-based scintillators for high-resolution nonplanar imaging.