Influence on loading terbium manganate on optical, thermal and electrical properties of polyvinyl alcohol nanocomposite films

In this article, optical, thermal and electrical properties of different wt% of TbMnO₃ (TMO) nanoparticles (NPs) loaded poly(vinyl alcohol) (PVA) films are reported in detail. The films are structurally characterised by X-ray diffraction spectroscopy and field emission scanning electron microscopy (FESEM). Optical parameters such as optical band gap energy \(\left( {{E_g}} \right)\), Urbach energy \(\left( {{E_U}} \right)\) are calculated. Red shift in the absorption band of the nanocomposite films indicates the complex formation between the nanofiller and the matrix. Thermal strength increases in TMO-PVA films than the pure PVA film. A reduction in the glass transition temperature \(\left( {{T_G}} \right)\) of the nanocomposite films is noticed with the insertion of TMO NPs in the PVA matrix. DC conductivity of the samples is explained by Mott’s variable range hopping model, Greave’s model, small polaron hopping model, non-adiabatic hopping model to explain the conduction mechanism. Modified Cole–Cole model explains the frequency variation of dielectric spectra. The relaxation peak position shifts towards lower frequency region with the inclusion of TMO filler in the PVA matrix indicating the decrease in mobility of the dipolar functional groups in the polymer chain. Modified Kohlrausch–Williams–Watts model is applied to explain the frequency dependent electric modulus spectra. AC conductivity of the films is explained by Jonscher’s power law. Correlated barrier hopping model is applied here. The presence of large current of the films at zero voltage may be due to the presence of ferroelectricity in the nanocomposite systems. Oxygen related defect states exist in the polymeric system which exhibit trapping of the charge carriers.