An insight into the role of titanium oxide nanofiller on the structural, optical, electrical, and dielectric characteristics of PS/PVK composite

Abstract

Nanocomposite films made of polystyrene (PS) and polyvinyl carbazole (PVK) and filled with varying quantities of titanium oxide (TiO2) nanoparticles (NPs) were prepared using the solution casting process. The TiO2 NPs' impact on the pure PS/PVK blend's structural, optical, and conductive properties was investigated and explained. X-ray diffraction (XRD) and Transmission electron microscopy (TEM) measurements indicate that the synthesized TiO2 NPs' size ranges between 12 and 32 nm and has a tetragonal anatase phase. The XRD scans also indicate that the PS/PVK filling with TiO2 NPs decreases the nanocomposite crystallinity. Fourier transform infrared (FTIR) analysis shows the main distinctive absorption peaks of PS and PVK, whose intensities changed randomly after filling. Moreover, the highest TiO2 NPs content showed a new peak at 449 cm-1. The UV/visible measurements showed that the optical energy gaps for the direct and indirect permitted transitions decreased as the TiO2 NPs content increased. Using impedance spectroscopy at room temperature, the AC electrical conductivity of the PS/PVK mixture containing TiO2 NPs was investigated over a broad frequency range from 10-1 to 107 Hz. It has been shown that the frequency dependence of AC electrical conductivity obeys Jonscher's rule, and the increase of TiO2 NPs concentration in the blend induces the formation of a percolating network within the composite. It has also been shown that the composite's dielectric loss and constant increase with nanoparticle concentration.

IncorporatedTiO2nanoparticles intoPVC/PMMApolymer blend for enhancing the optical and electrical/dielectric properties: Hybrid nanocomposite films for flexible optoelectronic devices

“…A sinusoidal voltage of varying frequencies is supplied to the sample, and the current amplitude and phase (relative to the applied voltage) are monitored. Assuming that the applied signal's frequency is f, the AC conductivity could be computed as follows 46 :…”