Phase Contraction, fluorescence quenching and formation of topological defects in chiral smectic C matrix by Cd_0.15Zn_0.85S/ZnS core/shell quantum dots dispersion: Faster electro-optic response for gadget displays

ABSTRACT

Cd_0.15Zn_0.85S/ZnS core/shell quantum dots (CSQDs) of size 7.54 ± 0.99 nm in diameter were prepared via gram-scale one-pot synthesis method and dispersed in a ferroelectric liquid crystalline (FLC) material into two different concentrations. Spectroscopic, electro-optical (E-O) and morphological characterisations of aforementioned composites have been carried out. CSQDs cause a significant contraction in the width of chiral smectic C (SmC*) mesophase that has also been theoretically verified. Diffusion–controlled processes are responsible for the fluorescence quenching in the FLC/CSQDs composites which has been explained by using the Stern–Volmer quenching equation. The mesomorphic investigation has revealed that helical deformation takes place in the FLC/CSQDs composites, due to which the temperature-dependent gradual growth of ferroelectric domains is noticed. The perturbed helical geometry evinces a new structure-property correlation having a molecular switching time of 135 μs that is 51% faster response as compared to the pristine system. Resultant spontaneous polarisation in the matrix of FLC/CSQDs composites is diminished because of the induced homeotropic and flexoelectric contributions. The faster E-O response and optical imaging are the fascinating features of the FLC/CSQDs composites that can probably be utilised in gadget displays.

Graphical abstract

KEYWORDS:

• Ferroelectric liquid crystal
• quantum dots
• electro-optical response
• fluorescence quenching
• dsc
• polarised optical microscopy

Acknowledgments

Prof. A. Hadj Sahraoui, the Director of UDSMM is gratefully acknowledged for his kind support and encouragement.

Disclosure statement

‘There are no conflicts to declare’.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

DPS sincerely thanks the UDSMM, ULCO for financial assistance;UDSMM, ULCO.