2014) Effect of CdSe quantum dots doping on the switching time, localised electric field and dielectric parameters of ferroelectric liquid crystal, Liquid Crystals, 41:12, 1889-1896, A systematic study highlighting the effect of cadmium selenide quantum dots (CdSe QDs) with varying concentrations of 0.05, 0.10 and 1.0 wt% doping on the electrooptical and dielectric parameters of ferroelectric liquid crystal (FLC) is presented. No considerable change is observed in phase transition temperature and tilt angle with CdSe QDs doping at lower and higher dopant level. Substantial enhancement of localised electric field at higher doping level (1.0 wt%) of CdSe QDs manifested the ≈48% reduction in the switching response of FLC nanocolloids at 30°C. Reduction in the spontaneous polarisation, dielectric constant and absorption strength could be attributed to the antiparallel correlation among dopant and matrix molecules, ion capturing in the capping additive layer and enhancement of the rotational viscosity of the nanocolloids, respectively. Goldstone mode relaxation frequency is found to be decreased with doping up to 0.10 wt% concentration and showed reverse effect at higher QDs concentration. QDs doping effect on the photoluminescence intensity is also discussed.

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Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.