[en] Fluorescence characteristics of solid solutions of CdSe/ZnS quantum dots (donor) and organic dye 3,3'-Diethyloxadicarbocyanine iodide (acceptor) in polymethylmetacrylate films have been investigated. The fluorescence intensity increase caused by the exciting radiation at the frequency of the QD absorption has been found for the films containing both QDs and DODCI. The abrupt rise of the fluorescence polarization degree has been observed at the high-frequency edge of the radiation spectrum of these films. Possible processes (nonradiative electronic excitation energy transfer, acceptor photodegradation) accounting for the experimental dependences are also discussed

[en] Spectral and kinetic characteristics of thermally activated delayed fluorescence (TADF) and phosphorescence of acriflavine in polyvinylalcohol films have been investigated. It was shown that TADF and phosphorescence decay times decrease due to fluorescence resonance energy transfer (FRET) as the concentration of the dye molecules increases. The luminescence spectra of the concentrated solutions are bathochromic shifted with respect to that of the deluted ones. Moreover, TADF and phosphorescence spectra of the concentrated solutions shift to the higher frequency region as emission decays. These effects are determined by the correlation between FRET direction and the heterogeneity of the triplet state lifetimes. Numerical simulations of the spectral and kinetic characteristics of TADF and phosphorescence were made by means of Monte-Carlo integrations, and results were compared with experimental data