The detection of ionising radiation is the focus of many strategic applications in both science and technology. Typically, the detection is carried out by scintillator materials that emit light following interaction with ionising radiation, which is detected by highly sensitive photodetectors. The fundamental characteristics of scintillators are the probability of interaction with ionising radiation, scintillation yield, scintillation rate, and stability to high doses of absorbed radiation, commonly referred to radiation hardness. For large scale applications, it is essential that scintillators can be manufactured in large sizes and massive quantities with cost-effective techniques in terms of both energy and raw material consumption.

Recently, lead halide perovskite nanocrystals (LHP-NCs)^[1] have emerged as promising nanoscintillators prized for their tuneable optical properties, radiation stability, high average Z-number and defect tolerance that enables high light yields and resistance to radiation damage up to extreme radiation levels^[2]. However, hot-injection synthesis methods used for high-optical-quality LHP NCs are not suitable for mass production and scalable LARP approaches are limited by concentration gradients in the reaction environment resulting in poorer optical performance. LHP-NCs are also susceptible to the fabrication protocols for polymeric matrices mostly due to the polarity of monomers, the presence of initiators and the polymerization temperature that lead to surface damage, NC dissolution and/or phase shift to non-emissive allotropes.

In this talk, I will report the fabrication of new ultrafast and radiation hard plastic scintillators based on CsPbBr₃ NCs formed within a polyacrylate matrix from precursor nanoparticles synthesized by a high-throughput, large scale turbo-emulsion method. Importantly, the formation of CsPbBr₃ NCs is accompanied by the gradual curing of quenching defects, resulting in large size nanocomposites with photoluminescence quantum yield of ~90% and light yield of about 1000 ph/MeV for NC loading of only 0.2wt%. Radiometry experiments after as much as 1 MGy of certified γ-ray dose from ⁶⁰Co source reveal perfect radiation hardness. Also fundamentally, pulsed X-ray scintillation measurements demonstrate ultrafast <60 ps scintillation due to multi-excitonic radiative decay as further confirmed by transient absorption measurements, indicating that CsPbBr₃ NCs are efficient scintillators despite the negative effects of nonradiative Auger decay.

The combination of fabrication scalability with ultrafast and stable scintillation under extreme operational conditions represents offers a valid platform for future advancements in radiation detection schemes, in particular for time-of-flight radiometry applications in high-energy physics and medical diagnostics.