Improved performance of cadmium selenide quantum dots-doped polymer stabilized cholesteric liquid crystals for light shutter

Abstract

ABSTRACT In this work, cadmium selenide quantum dots (CdSe QDs)-doped polymer stabilized cholesteric liquid crystals composites (PSCLC) are proposed for low-power light shutters. CdSe QDs with different concentrations, (0.1 and 0.25 wt.%) into PSCLC composites are fabricated and studied. The phase-dependent and morphological studies are investigated in all the samples. The morphological study reveals that doped sample transform from planar to homeotropic type of orientation at low voltage (~15 V), at an optimum concentration 0.1 wt. % of CdSe QDs in PSCLC. Dielectric analysis infers that dispersion of CdSe QDs increases the permittivity (~36%) of the composites. At 0.1 wt.% QDs-doped PSCLC system, the dielectric anisotropy also increases, however a decrease in splay elastic constant could be seen. Voltage dependence on transmission behaviour also shows that the threshold as well as saturation voltages are lower (6.5 V and 19.5 V, respectively) for 0.1 wt.% QDs-doped system than undoped sample. This signifies that desired alignment to the liquid crystal molecules is easily achieved at low electrical energy by the incorporation of CdSe QDs. CdSe QDs may be incorporated into PSCLC to develop novel functional devices operated at low power.