We investigated the absorption and luminescence spectra and the low-frequency spectra of dielectric losses of the nematic liquid crystal (NLC) suspensions with quantum dots (QDs) CdSe/ZnS with a core diameter of 3.5 nm and 5.0 nm. The changing of luminescence intensity and dielectric losses in the region below 103 Hz were observed as result variation of a concentration and a QDs size in the spectra of NLC/QDs suspensions in comparison with the pure NLC. Luminescence quenching of the NLC and the increase of dielectric loss in the spectra were found with the increasing CdSe/ZnS concentration in interval between 0.07 - 0.3 wt. %.
KEYWORDS: Semiconductors, Data modeling, Luminescence, Molecules, Energy transfer, Quantum dots, Resonance energy transfer, Fluorescence resonance energy transfer, Positron emission tomography, Molecular energy transfer
Hybrid structures based on CdSe/ZnS quantum dots and porphyrin molecules with effective energy transfer were formed in samples of polymer track pore membrane. It was observed that energy transfer efficiency depends on quantum dot size and correlates with overlapping integral between quantum dot photoluminescence and porphyrin absorption spectra inherent for Förster Resonant Energy Transfer, FRET. However, a noticeable deviation of experimental FRET efficiency dependence on an acceptor concentration from theoretical ones was observed for all donor-acceptor pairs. A gradient of donor and acceptor concentrations in the matrix is considered as the most probable reason of this deviation. A theoretical model describing energy transfer in a rigid solution with a gradient of particle concentration is proposed.