Study FTIR and AC Conductivity of Nanocomposite Electrolytes

In the present work polymer electrolytes were formulated using the solvent casting technique. Under special conditions, the electrolyte content was of fixed ratio of polyvinylpyrolidone (PVP): polyacrylonitrile (PAN) (25:75), ethylene carbonate (EC) and propylene carbonate (PC) (1:1) with 10% of potassium iodide (KI) and iodine I2 = 10% by weight of KI. The conductivity was increased with the addition of ZnO nanoparticles. It is also increased with the temperature increase within the range (293 to 343 K). The conductivity reaches maximum value of about (0.0296 S.cm-1) with (0.25 g) ZnO. The results of FTIR for blend electrolytes indicated a significant degree of interaction between the polymer blend (PVP and PAN) and the KI salt. From the electrolyte observations of the nanocomposites, the broad peak became narrower after adding the ZnO nanoparticle to the KI salt. The dielectric reaction decreased with the increase of the frequency at room temperature. The high dielectric permittivity of the polymer at lower frequencies can be attributed to the dipoles having sufficient time to get aligned with the electric field, resulting in higher polarization.

Size, Shape, and Material Effects in Ferroelectric Octahedral Nanoparticles

Composite materials composed of multiferroelectric nanoparticles in dielectric matrixes have attracted enormous attention for their potential applications in developing future functional devices. However, the functionalities of ferroelectric nanoparticles depend on shapes, sizes, and materials. In this paper, a time-dependent Landau-Ginzburg method has been used and combined with a method as the coupled-physics finite-element-method-based simulations are used to illustrate the polarization behavior in isolated BaTiO3 or PbTiO3 octahedral nanoparticles embedded in a dielectric medium, like SrTiO3 (ST, high dielectric permittivity) and amorphous silica (a-SiO2, low dielectric permittivity). The equilibrium polarization topology of the octahedral nanoparticle is strongly affected by the choice of inclusion and the size of matrix materials. Also, there are three equilibrium polarization patterns, i.e., monodomain, vortex-like, and multidomain, because of the various sizes and material parameters combination. There is a critical particle size below which ferroelectricity vanishes in our calculations. This size of the PbTiO3 octahedral nanoparticle is 2.5 and 3.6 nm for high- and low-permittivity matrix materials, respectively. However, this size of the BaTiO3 octahedral nanoparticle is 3.6 nm regardless of the matrix materials.

Development of ferroelectric nematic fluids with giant-ε dielectricity and nonlinear optical properties

Superhigh-ε materials that exhibit exceptionally high dielectric permittivity are recognized as potential candidates for a wide range of next-generation photonic and electronic devices. In general, achieving a high-ε state requires low material symmetry, as most known high-ε materials are symmetry-broken crystals. There are few reports on fluidic high-ε dielectrics. Here, we demonstrate how small molecules with high polarity, enabled by rational molecular design and machine learning analyses, enable the development of superhigh-ε fluid materials (dielectric permittivity, ε > 104) with strong second harmonic generation and macroscopic spontaneous polar ordering. The polar structures are confirmed to be identical for all the synthesized materials. Furthermore, adapting this strategy to high–molecular weight systems allows us to generalize this approach to polar polymeric materials, creating polar soft matters with spontaneous symmetry breaking.

Enhanced dielectric properties with a significantly reduced loss tangent in (Mg2+, Al3+) co-doped CaCu3Ti4O12 ceramics: DFT and experimental investigations

Mg and Al atoms preferentially occupy Cu sites, creating liquid-phase sintering decomposition at grain boundary layers. This results in very high dielectric permittivity and a low loss tangent of the CaCu2.95Mg0.05Ti3.95Al0.05O12 ceramic.