In-situ microstructure modulation of fast temporal-decay (C₄H₉NH₃)₂PbBr₄ composite film for high spatial resolution and dynamic X-ray imaging

Metal halide perovskite scintillators have emerged as promising candidates for X-ray imaging owing to their excellent scintillation performance and solution processability. However, simultaneously achieving high spatial and temporal resolution in scintillator films remains challenging. Increasing scintillator loading improves light yield but also induces particle aggregation and optical photon scattering, ultimately degrading spatial resolution. Here, the (C₄H₉NH₃)₂PbBr₄@Poly(methyl methacrylate) (BA₂PbBr₄@PMMA) composite films with suppressed particle aggregation at high scintillator particle loading were achieved by in-situ regulating polymer confinement in the film preparation process, simultaneously enabling X-ray imaging with high spatial resolution and fast decay time. By establishing an adequate solvation environment, uniformly dispersed PMMA chains introduce homogeneous polymer confinement during crystallization, suppressing both solute aggregation and disorderly grain growth. The resulting uniformly dispersed fine-particle microstructure effectively suppresses optical photon scattering, thereby enhancing radioluminescence intensity, optical transmittance and the spatial resolution of the BA₂PbBr₄@PMMA scintillation film (from 6.0 to 17.5 lp mm⁻¹). Furthermore, the composite films exhibit a fast decay time with an average value of 3.32 ns, effectively eliminating ghosting effects in dynamic imaging. This work provides a general strategy for designing scintillator films with high light output and fast decay, and offers insights into microstructure engineering for optoelectronic devices.