Investigation of triplex CaAl2ZnO5 nanocrystals on electrical permittivity, optical and structural characteristics of PVA nanocomposite films

Abstract

Nanocomposite (NC) films of polyvinyl alcohol (PVA)/calcium aluminum-doped zincate (CaAl2ZnO5) have been fabricated with varying amounts, namely 2, 4, 6 and 8 wt% of CaAl2ZnO5 nanoparticles (NPs) by solution casting technique. TEM data showed that an average particle size of CaAl2ZnO5 NPs is ~ 25 nm. The effect of CaAl2ZnO5 content on structural and morphological behaviors has been established by Fourier-transform infrared spectroscopy and scanning electron microscopy, respectively. The photo-response of NCs was derived by UV–visible spectroscopy where the band gap energy (Eg) reduced from 5.25 eV for PVA to 2.82 eV for PVA/8 wt% CaAl2ZnO5 NC film. The dielectric permittivity and current–voltage (I–V) characteristics were studied using LCR—meter in frequency range of 50 Hz–5000 kHz. The relative dielectric constant (e′) was increased from 15 to 65 with increase in NPs content from 0 to 8 wt%. The PVA NC with 8 wt% CaAl2ZnO5NPs raises the ac conductivity to 3.35 × 10−5 S cm−1 at room temperature. The cyclic voltammetry (CV) tests have been performed to calculate the specific capacitance of the NCs as a positive electrode against Ag/AgCl as reference electrode. The specific capacitance increases from 1. Fg−1 for PVA to 3.69 Fg−1 for PVA/8 wt% CaAl2ZnO5 NC. These behaviors will support the possible applications in optical display devices and micro-electrical and electronic applications.