Speaker
Description
Scintillation detectors are essential in high-energy physics, medical diagnostics, and radiation monitoring, where fast and efficient conversion of ionizing radiation into visible light is required. Lead halide inorganic perovskites have recently emerged as promising next-generation scintillators due to their high atomic number, strong X-ray attenuation, high radioluminescence yield, and intrinsically fast emission. Among them, the three-dimensional (3D) perovskite CsPbBr3 has been widely investigated for scintillation applications. In contrast, the zero-dimensional (0D) phase Cs4PbBr6 exhibits peculiar defect-mediated emission behavior whose role in scintillation remains unclear and debated. Although mixed-phase systems containing both structures are frequently obtained during synthesis, the specific contribution of the 0D phase to scintillation performance has not been systematically explored.
A simple, reproducible solvent–antisolvent synthesis route is developed to deliberately modulate the relative proportion of the 3D and 0D phases within polycrystalline cesium lead bromide powders. The method relies on controlled incremental additions of water during synthesis, which selectively promote the formation of the 3D phase while preserving a tunable fraction of the 0D one. This strategy enables a systematic investigation of how the coexistence and ratio of CsPbBr3 and Cs4PbBr6 affect scintillation behavior, offering a unique opportunity to clarify the functional role of the 0D phase.
Scintillation measurements under X-ray excitation reveal that samples synthesized with low water volumes, corresponding to a higher fraction of the 0D phase, exhibit increased scintillation yield combined with an ultrafast decay time. These findings indicate that defect states associated with the 0D structure actively participate in radiative recombination processes under ionizing radiation. Cathodoluminescence and temperature-dependent radioluminescence analyses further support a defect-driven scintillation mechanism, highlighting the interplay between structural confinement and defect chemistry in determining emission dynamics. This provides new insight into the emission mechanism of Cs4PbBr6 and establishes design principles for optimizing mixed-phase perovskites for radiation detection.
Building on these materials insights, additive manufacturing is exploited for the first time to fabricate scintillators with complex three-dimensional geometries based on perovskite materials. An innovative nanocomposite is developed by dispersing Cs4PbBr6 powders into a thermosetting photocurable resin, enabling processing via stereolithography. The high-Z lead-based perovskite filler ensures efficient interaction with ionizing radiation and conversion into visible light, while the polymer matrix provides printability, mechanical stability, and environmental protection.
Rheological and photopolymerization studies demonstrate that the inclusion of the perovskite filler does not significantly alter the viscosity, flow behavior, or curing kinetics of the resin, preserving its suitability for high-resolution stereolithographic printing. Optical and radioluminescence characterizations confirm that embedding the perovskite within the polymer matrix does not compromise its emission properties. Encapsulation enhances environmental stability, protecting the perovskite from moisture and degradation while maintaining a fast scintillation response.
This combined materials and manufacturing approach introduces a new class of 3D-printable plastic scintillators that merge the outstanding radiation detection capabilities of inorganic lead halide perovskites with the versatility and scalability of additive manufacturing. The results not only deepen the understanding of defect-mediated scintillation mechanisms in mixed-phase perovskites but also demonstrate a practical pathway toward customizable, stable, and high-performance scintillation devices for advanced radiation sensing applications.