Probing the impact of carbon quantum dots on partially unwound helical mode in ferroelectric liquid crystals
Abstract
We report the modulation in dielectric properties of a ferroelectric liquid crystal (FLC) by using carbon quantum dots (CQDs) of size ∼4-5 nm. The appearance of a low frequency dielectric relaxation mode in the FLC, called the partially unwound helical mode (p-UHM), is controlled by CQDs with a FLC material in two different ways. Firstly, CQDs are dispersed into the bulk of the FLC before filling into a sample cell, and secondly, they are deposited onto the surface of a substrate. In both cases, the p-UHM has been found suppressed due to the modulation of a helicoidal structure at the interface of the FLC and the surface of the substrate of the sample cell. It has also been confirmed that CQDs at the interface of the FLC and the surface of the substrate have not affected the intrinsic properties of the FLC material. On the other hand, CQDs in the bulk of the FLC have shown remarkable variations in the fundamental properties of the FLC material. The suppression of the dielectric mode is confirmed by high-resolution dielectric spectroscopy, optical textures, and contact angle measurements. The concept of appearance and disappearance of the p-UHM process leads to the understanding of FLC systems in confined geometries for various display and non-display applications.
- Publication:
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Journal of Applied Physics
- Pub Date:
- March 2019
- DOI:
- 10.1063/1.5082903
- Bibcode:
- 2019JAP...125l5108G