Enhanced dielectric properties of Nematic liquid crystal doped with ferroelectric nanoparticles

ABSTRACT

In this work, we report the electrical and dielectric behaviours of a ferroelectric nanoparticle-doped liquid crystal cell using the impedance and dielectric spectroscopic measurements in the frequency range 1 Hz – 2 MHz. The impact suitable equivalent electric circuit is proposed and the circuit parameters are obtained using the impedance spectroscopy technique. The impact of the nanoparticles on these parameters which attributed to mobile charge carriers accumulating near the electrodes of the cell is demonstrated and discussed. The presence of nanoparticles is found to increase the dielectric anisotropy (Δε) with maintaining a low loss tangent. As a result, a highly Δε = 120 for frequencies <100 Hz and Δε = 27 for f > 100 Hz is achieved. The dielectric measurements show that the presence of the nanoparticles leads to the appearance of low-frequency relaxation (f ≈ 500 Hz) due to the interfacial polarisation, a slight increase in the diffusion coefficient and the ion mobility. This work provides a foundation to quantitatively investigate the interface effect in dielectric composites.

Graphical Abstract

KEYWORDS:

• Liquid crystal
• nanoparticles
• impedance spectroscopy
• equivalent electric circuit
• dielectric properties

Disclosure statement

No potential conflict of interest was reported by the author(s).