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Polymer Composite Scintillators Based on Halide Perovskite Nanocrystals for X-Ray Imaging
A. A. Knysh$^1$$^,$$^2$, P. M. Sokolov$^1$$^,$$^2$, V. V. Sosnovtsev$^1$, P. S. Samokhvalov$^1$$^,$$^2$
$^1$National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, 115409 Russia
$^2$Life Improvement by Future Technologies (LIFT) Center, Moscow, 121205 Russia
The performance of indirect X-ray imaging systems depends on the ability of a scintillator to efficiently convert X-rays into visible light while preserving the spatial distribution of the transmitted radiation. High-resolution imaging therefore requires efficient X-ray absorption and radioluminescence (RL) combined with thin, optically homogeneous scintillation layers. Metal-halide perovskites are promising for this purpose due to their strong X-ray absorption, efficient photoluminescence (PL), and compatibility with solution-based fabrication [1]. In particular, CsPbBr$_{3}$ perovskite nanocrystals (PNCs) exhibit a high effective atomic number Z$_{eff}$ ≈ 63.2) and PL quantum yields approaching 100% [2], while their incorporation into polymer matrices enables the fabrication of thin-film composite scintillators.
In this work, thin-film scintillators based on CsPbBr$_{3}$ PNCs embedded in a modified poly(methyl methacrylate) (PMMA) matrix were fabricated and tested for X-ray imaging. Films with thicknesses up to approximately 500 μm were found to be preferable for high-resolution imaging. A dedicated experimental setup was assembled in which the radiographic image was formed by the X-ray shadow of the investigated object projected onto the scintillator surface and converted into visible emission. The image was recorded using a conventional digital camera (Canon EOS R6 Mark II), with an Apogee 5500 Series X-ray tube operated at 50 kV as the radiation source. Using a TYP 39-A test pattern with 0.03-mm-thick lead lines, a spatial resolution of approximately 8-9 lp/mm was achieved at an exposure time of 5-10 s.
The thermal stability of both PL and RL intensities was also investigated. Only a minor decrease in emission intensity relative to its initial value was observed after the heating-cooling cycle. Radioluminescence remained detectable even at 445 K, while the relative decline of RL intensity was lower than that of CsI:Tl, BGO and GAGG:Mg,Ce over the investigated temperature range.
Overall, the results demonstrate the potential of CsPbBr$_{3}$/polymer thin-film scintillators for high-resolution X-ray imaging using a simple optical readout scheme.
Keywords: scintillators, CsPbBr$_{3}$, radioluminescence, X-ray imaging, spatial resolution.
REFERENCES
- Yang, Z. et al. Designer Bright and Fast CsPbBr$_{3}$ Perovskite Nanocrystal Scintillators for High-Speed X-Ray Imaging. Nat Commun 2024, 15 (1), 8870.
- Knysh, A. et al. Principles of Chemical Designing of Styrene-Based Plastic Scintillators Doped with Quantum Dots. Phys. Atom. Nuclei 2024, 87 (11), 1744–1749.
