Ultrafast Laser Irradiation Enhances Crystallinity and Photoluminescence of Colloidal CsPbBr₃ Nanocrystals for High-Performance X-ray Detection

Colloidal CsPbBr3 nanocrystals (NCs) have emerged as promising materials for optoelectronic and photonic applications due to their exceptional optical properties. Photon-induced processing has become a viable substitute for perovskite NC modification. However, postsynthesis laser irradiation often compromises their pristine morphology. Here, we demonstrate a rapid and scalable femtosecond laser irradiation strategy to simultaneously improve the crystallinity and PL intensity (up to 50%) in CsPbBr3 NCs without significantly altering their morphology and size distribution. By optimizing irradiation time (≤5 min), we achieve a polycrystalline-to-single-crystalline transition, reducing defect density and extending carrier lifetimes from 3.50 to 8.91 ns. The treated NCs exhibit superior X-ray detection performance, with a 5-fold increase in switching ratio (Ion/Ioff = 47) and enhanced sensitivity (28.3 μC Gyair–1 cm–2 vs 11.7 μC Gyair–1 cm–2 for untreated NCs). This work presents a practical, time-efficient approach to tailoring perovskite NCs for high-performance radiation detectors while preserving their intrinsic optoelectronic properties.