DOI: https://doi.org/10.30970/jps.03.213
REFLECTION SPECTRA AND LUMINESCENCE-KINETIC PARAMETERS OF PEROVSKITE-LIKE AmPbnBrp CRYSTALS (A = Cs, Rb, K; m = 1, 4; n = 1, 2; p = 3, 5, 6)
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Journal of Physical Studies 3(2), 213–223 (1999)
DOI: https://doi.org/10.30970/jps.03.213 REFLECTION SPECTRA AND LUMINESCENCE-KINETIC PARAMETERS OF PEROVSKITE-LIKE AmPbnBrp CRYSTALS (A = Cs, Rb, K; m = 1, 4; n = 1, 2; p = 3, 5, 6) |
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S. V. Myagkota
Physics Department, the Ivan Franko State University of Lviv,
8 Kyrylo i Mefodii Str., Lviv, UA-290005, Ukraine
Lviv Academy of Veterinary Medecine,
50 Pekarska Str., Lviv, UA-290010, Ukraine
The reflection spectra of the CsPbBr$_{3}$, RbPbBr$_{3}$, RbPb$_{2}$Br$_{5}$, KPb$_{2}$Br$_{5}$, Rb$_{4}$PbBr$_{6}$ crystals in the fundamental absorbtion region (at the energies 2.0$\div$5.5eV, $T$= 300~K) and the exciton reflection spectra of the CsPbBr$_{3}$, RbPbBr$_{3}$, RbPb$_{2}$Br$_{5}$, KPb$_{2}$Br$_{5}$, Rb$_{4}$PbBr$_{6}$ crystals and their luminescence kinetic parameters are studied for the temperature range $T=4.2\div 300$~K. The structure of the fundamental reflection spectra of the mentioned above crystals in the longwave region is determined by the transition within the octahedral quasi–complex of [PbBr$_{6}$]$^{4-}$. The structure of the exciton reflection peak in the CsPbBr$_{3}$ and RbPbBr$_{3}$ represents a Vanje–Mott quasi–hydrogen series while a doublet structure is characteristic of the RbPb$_{2}$Br$_{5}$ and KPb$_{2}$Br$_{5}$ crystals. This structure is closely related to the nature of their intrinsic luminescence. For the CsPbBr$_{3}$ and RbPbBr$_{3}$ crystals, luminescence of free and localised excitons and their scattering at different phonons are characteristic, while RbPb$_{2}$Br$_{5}$ and KPb$_{2}$Br$_{5}$ crystals show luminescence of self–trapped near defects\ excitons. The nature of emission relaxation of intrinsic electron excitations and the structure of exciton reflection peaks is linked with the coefficient of charge of the unit cell. Luminescence studies confirmed the incongruent character of the Rb$_{4}$PbBr$_{6}$ crystalline compound melting as well as a rescrystallization decay of the RbPbBr$_{3}$ crystal into Rb$_{4}$PbBr$_{6}$ and RbPb$_{2}$Br$_{5}$ phases.