Solution Processed Hundred-Micron Scale Vertical Growth of Low-Symmetrical Zero-Dimensional Metal Halide for High-Performance X-Ray Imaging

Scintillator films with high light output and low cross-talk are essential for highly sensitive and high-resolution X-ray imaging applications. However, only specific scintillators prepared with high-cost method or pixelated template meet these demands. Solution processed strategies possess the merit of low-cost while scintillator particles are usually in chaos with severe light scattering, especially for thick films up to hundreds of microns, resulting in poor imaging sensitivity and resolution. Herein, we demonstrate that low-symmetrical zero-dimensional Cs3Cu2I5 scintillator can grow longitudinally with spray-coating strategy with the assistance of crystal facet inhibitor. The additive, triallyl isocyanurate, exhibits preferred crystal face binding ability, inducing oriented growth and well-defined columnar structure with large thickness more than one hundred microns. The final scintillator films show higher luminescence polarity and light output, contributing to remarkable improvement in light yield and imaging resolution of 71% and 81% compared with the control sample, respectively. Besides, the added monomer crosslinks under annealing and provide robust protection, leading to excellent radiation hardness and storage stability under ambient environment. By virtue of the negligible afterglow, artifact-free X-ray imaging at a frame rate of 3840 fps is fulfilled, indicating the promising prospects of this strategy for application in low-cost, high-performance fast X-ray imaging.