Scintillation Properties of CsPbBr₃ Nanocrystals Prepared by Ligand-Assisted Reprecipitation and Dual Effect of Polyacrylate Encapsulation toward Scalable Ultrafast Radiation Detectors

Abstract

Lead halide perovskite nanocrystals (LHP-NCs) embedded in polymeric hosts are gaining attention as scalable and low-cost scintillation detectors for technologically relevant applications. Despite rapid progress, little is currently known about the scintillation properties and stability of LHP-NCs prepared by the ligand assisted reprecipitation (LARP) method, which allows mass scalability at room temperature unmatched by any other type of nanostructure, and the implications of incorporating LHP-NCs into polyacrylate hosts are still largely debated. Here, we show that LARP-synthesized CsPbBr 3 NCs are comparable to particles from hot-injection routes and unravel the dual effect of polyacrylate incorporation, where the partial degradation of LHP-NCs luminescence is counterbalanced by the passivation of electron-poor defects by the host acrylic groups. Experiments on NCs with tailored surface defects show that the balance between such antithetical effects of polymer embedding is determined by the surface defect density of the NCs and provide guidelines for further material optimization.

Advances in Perovskite Nanocrystals and Nanocomposites for Scintillation Applications

“…These results, which highlight the close relationship between surface defect density and RL efficiency, provide a spectroscopic platform for the development of novel nanoscintillators that are competitive or even superior to commercial BGO or BaF 2 crystals . A similar effect to fluorine passivation was observed by Cova et al . in CsPbBr 3 PNCs embedded in PMMA nanocomposites, where the passivation of uncoordinated Pb sites on the NCs surfaces by the electron-rich acrylic groups of PMMA restored the band-edge character of RL, as demonstrated by the disappearance of the pronounced redshift of the RL of bare NCs from the corresponding PL, ascribed to the emission from a manifold of shallow defects (Figure g).…”

“…Dashed lines are the excitonic and defect contributions to the RL. Panels g–i are adapted from ref . Copyright 2024, American Chemical Society.…”

“…The fitting curve is shown with solid line also reporting the fit parameters. Adapted from ref . Copyright 2024, American Chemical Society.…”

“…This method allows the production of homogeneous thin nanocomposites (up to hundreds of μm), which are typically used as screens for X-ray imaging, − an application that does not require large thicknesses but does require high precision. Finally, massive nanocomposites for applications in high-energy physics and/or rare event detection are typically obtained using bulk polymerization techniques. , All these strategies adopted to obtain powders, coatings, and bulk scintillators are schematically shown in Figure and described in details in the following sections, with particular emphasis on preserving, or even improving, the scintillating properties of PNC emitters once embedded in polymeric matrices, , which represents the most challenging aspect of nanocomposite fabrication.…”

“…This has been achieved by Yang et al on specifically surface treated CsPbBr 3 PNCs, demonstrating RL intensity stability in PNCs up to 42 kGy dose of 60 Co γ-rays (at a dose rate of 0.45 kGy h –1 ). A different aspect of radiation hardness is that of high-energy particle colliders and nuclear reactors, where the doses involved are up to 5 or 6 orders of magnitude higher than in X-ray imaging and typically exceed the extreme dose of 1 MGy. , To date, only a few studies have directly addressed radiation hardness in PNCs above 10 5 Gy, mainly from Brovelli and co-workers ,, and from Ostrikov and co-workers , using 60 Co γ-rays. In particular, it has been shown that radiation hardness is an intrinsic property of PNCs, regardless of whether they are synthesized by HI or by LARP techniques, , and that this property is retained when they are embedded in polyacrylate nanocomposites (Figure c,d) obtained by solvent evaporation or by UV-initiated free-radical polymerization (Figure e).…”