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2015): Influence of CdSe quantum dot on molecular/ionic relaxation phenomenon and change in physical parameters of ferroelectric liquid crystal, Liquid Crystals, Spherical cadmium selenide (CdSe) quantum dots (QDs), capped with octadecylamine, dispersed in ferroelectric liquid crystal (FLC), can remarkably alter the electro-optical (E-O) parameters (material parameters) of the host compound. Here we present an E-O, dielectric, surface anchoring and fluorescence study demonstrating that the physical properties of host FLC strongly depend on the dopant (QD) concentration. The addition of QDs in FLC changes the surface anchoring of FLC molecules, which results the change in E-O parameters of pristine FLC as a function of QDs concentration. The ion-polarisation coupling induces a new temperature-dependent weak ionic relaxation mode (TDWIRM) in FLC-QDs mixture at a certain concentration of QDs. Dipolar coupling between CdSe QDs and FLC molecules readjust the dielectric properties and molecular/ionic relaxation phenomenon in the FLC-QDs mixtures. The fluorescence of FLC-QDs mixtures is probably due to the coupling between the exciton and photon in LC medium, which leads the radiative process. The behaviour of fluorescence property of FLC-QDs mixtures reveals that the concentration of uniform-sized QDs only changes the fluorescence intensity of the FLC-QDs mixtures.

The dielectric properties of pure nematic liquid crystal (BKS/B07) and dye doped (Rhodamine B and Anthraquinone) nematic liquid crystal have been investigated in a wide frequency range of 1 kHz to 10 MHz through the dielectric spectroscopic method at varying temperature. In addition to this optical transmittance and textures of the samples have also been observed with a polarizing microscope

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The effect of QDs on the dielectric and electro-optical (E-O) properties of different ferroelectric liquid crystal matrices has been studied in the SmC * phase. A substantial change in the different parameters like tilt angle, spontaneous polarization and relative permittivity has been observed for the doped system. For the better understanding of the effect of QDs on FLC relaxation process another quantum dot CdSe has been dispersed in two other FLC systems 16/100 and DOBAMBC. The effect of QDs on the three FLC systems on relaxation behavior attributes to the alteration of tilt angle in different way in different doped system. This difference in relaxation behavior is observed due to the dissimilar composition and structure of FLC mixture and FLC molecule.