OPTICAL PROPERTIES OF COMPOSITES BASED ON CSPBBR 3 PEROVSKITE NANOCRYSTALS AND POLYMER MATRICES AS PROMISING COMPONENTS OF NEXT-GENERATION SCINTILLATION DETECTORS

There is a growing demand for materials for detecting ionizing radiation, which has led to the expansion of research and development of new scintillators. Typically, classical scintillators are synthesized by crystallizing materials at high temperatures, and their photoluminescence (PL) is difficult to tune in the visible spectral range. Therefore, composite materials based on CsPbBr ₃ perovskite nanocrystals (PNCs), which have a high average atomic number and a long charge-carrier diffusion length, are of particular interest and may be used for detecting ionizing radiation. Unlike bulk scintillators, PNCs are synthesized in solution at relatively low temperatures, with the PL tunable throughout the visible spectrum. The main problem limiting the widespread use of PNCs is their low stability upon contact with the environment. This study presents the results of experiments on the encapsulation of PNCs in a polystyrene matrix, the evaluation of the changes in the luminescence quantum yield (QY) over time, and the development of a technique for studying the amplitude characteristics of signals registered during the interaction of α-particles with composite materials based on CsPbBr ₃ PNCs and polystyrene. The study has shown that composite samples based on PNCs and polystyrene retain a stable luminescence QY for two weeks. Using a ²⁴¹ Am source with a characteristic α-particle energy of about 4.6 MeV and 60 γ-ray energy of 60 keV, the light output values were calculated for the samples studied. The maximum light output was 20% of that of the standard “fast” plastic scintillator (POPOP) at a volume fraction of PNCs in the composite of less than 1%, which indicates the prospect of PNCs as a basis for composite scintillators and their further use in X-ray diagnosis.

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