Electro-optical behaviour and dielectric dynamics of harvested ferroelectric LiNbO3 nanoparticle-doped ferroelectric liquid crystal nanocolloids

Abstract

Nanocolloids comprising harvested ferroelectric LiNbO₃ nanoparticles (≈25 nm) and ferroelectric liquid crystals were prepared and investigated. The impact of the amount of dispersed nanoparticles (0.01 wt%, 0.05 wt%, 0.10 wt%) on the electro-optical, dielectric and material parameters of the ferroelectric liquid crystals (FLCs) has been demonstrated. The dopant strongly influences the switching characteristics and has an effect on the saturation voltage of the FLC materials. Electro-optical measurements demonstrated that a relatively large (0.10 wt%) LiNbO₃ dopant concentration decreases the response time and saturation voltage by approximately 40% and 25% respectively, compared with non-doped FLCs. The effect of LiNbO₃ nanoparticle concentration on the material and dynamical parameters (i.e. spontaneous polarization, dielectric permittivity, dielectric absorption, dielectric strength, dc conductivity, and rotational viscosity) is presented. The observed behaviours are discussed in terms of capture of impurity ions on the surface of the harvested LiNbO₃ nanoparticles. Ion capturing leads to enhancement of the localized electric field inside the smectic layers. The fast switching response and the low operational voltage of these FLC nanocolloids support their application in nanometric scale electronic devices.