Registration Number
0225U002752,
(0122U001860)
, R & D reports
Title
Relaxation of electronic excitations in inorganic halogen perovskites of ABX3 type
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Релаксація електронних збуджень в неорганічних галоїдних перовськитах типу ABX3
Head
Voloshynovskyi Anatolii S., Доктор фізико-математичних наук
Registration Date
02-04-2025
Organization
Ivan Franko National University of Lviv
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The aim of the project is to elucidate the mechanisms of electronic and exciton relaxation in new functional materials based on halogen perovskites ABX3 (A = Cs, Rb, K; B = Pb, Sn; X = F, Cl, Br, I). The project involves the synthesis and study of physical parameters of inorganic halide perovskites and nanostructures based on them. The main task will be to establish the laws of radiative relaxation of electronic excitations, the nature of emission centers, their spectral and kinetic characteristics. The problems of developing scintillation detectors with picosecond time resolution, development of methods for obtaining nanoparticles embedded into bulk materials for luminescent materials, increasing the efficiency of photoconverters and photodetectors, expanding the spectral range of emission, increasing the stability of perovskite materials will be solved. To achieve the aims the project provides: 1) grown of perovskite single crystals, micro- and nanocrystals incapsulated in dielectric matrices; 2) synthesis of colloidal nanoparticles and nanostructures based on them; 3) the study of luminescent parameters of samples in the temperature range of 10-300 K under the optical, synchrotron, X-ray and femtosecond laser excitation; 4) calculation of exchange interaction in exciton states, calculation of the band energy structure of perovskites by taking into account the spin-orbit interaction and the Rashba effect; 5) development of a model of emission centers and the mechanism of the scintillation process in single crystals and nanocomposites based on perovskites.
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The project is aimed at elucidating the nature of electronic and excitonic processes in new functional materials based on halide perovskites of the ABX3 type (A = Cs, Rb, K; B = Pb, Sn; X = F, Cl, Br, I), which have acquired significant practical importance in the fields of LED technology, solar cells, radiation detectors and biomedicine. The main attention is focused on the mechanisms of radiative relaxation of electronic excitations, determination of emission centers and spectral-kinetic properties upon excitation by ionizing radiation. The synthesis and growth of single crystals and perovskite nanoparticles in various matrices were carried out, the peculiarities of the interaction of structure and properties were clarified, in particular the quantum-size effect, the dynamic Rashba effect and violations of local symmetry of the crystal lattice. Markers for identifying Wannier-Mott and Rashba excitons in the luminescence of crystals and nanoparticles were considered. The temperature and pressure dependences of the emission spectra indicate a significant contribution of exciton-phonon interaction to the features of different types of excitons, direct excitons and indirect Rashb excitons. The results obtained indicate the prospects of CsPbCl3 crystals as fast scintillators at low temperatures, demonstrating high luminescence intensity with ultrafast kinetics. Studies have shown a positive effect of activators, such as cadmium, on the spectral properties of luminescence, which allows the use of activated single crystals for positron emission tomography. Features of the luminescence of CsPbBr3-Yb have been established, which open up opportunities for creating sources of IR radiation. The developed approaches and project results significantly expand the understanding of electronic and excitonic processes in perovskites, which is of fundamental importance for further research and the creation of new functional materials.
Product Description
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Ihnatsevych Serhii O.
Antoniak Oleh T.
Vistovskyi Vitalii V.
Hloskovska Nataliia V.
Malyi Taras S.
Khapko Zenon A.
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2025-04-02
