Studies on optical properties, thermal stability and electrical conductivity of copper alumina nanoparticles-reinforced Poly(pyrrole-co-indole) for optoelectronic devices

Abstract

This work focused on the effect of copper alumina (Cu–Al₂O₃) nanoparticles in poly(pyrrole-co-indole) (PPy-co-PIN) on optical properties, thermal stability, alternating current (AC) conductivity, direct current (DC) conductivity and dielectric properties at different temperatures. Consistent distribution of Cu–Al₂O₃ nanoparticles within the copolymer was observed from field-emission scanning electron microscopy. The single absorption seen (range 270 nm) in the UV spectra was due to π–π^* transitions in the copolymeric materials. The minimum optical bandgap energy was observed for 5 wt% nanocomposite. From thermogravimetric analysis graph, maximum thermal resistance was observed for 7 wt% nanocomposite. The AC conductivity and dielectric parameters were dependent on both temperature and nanofillers loading and the maximum properties were found for 5 wt% nanocomposite. The AC conductivity and dielectric constant of 5 wt% nanocomposites were increased by 4.5 and 3 times, respectively, in comparison to (PPy-co-PIN). The decrease in activation energy with an increase in the content of Cu–Al₂O₃ nanofillers and inverse dependence of Nyquist plot with temperature suggested semiconducting nature. The DC conductivity of copolymer was enhanced with encapsulation of Cu–Al₂O₃ nanoparticles and the change in conductivity was correlated with Scarisbrick, Bueche and McCullough models. The McCullough model was in compromise with experimental conductivity values as it considers interfacial interactions. The match in theoretical and experimental conductivity values was advocating the presence of an efficient conductive pathway. The excellent properties of (PPy-co-PIN)/Cu–Al₂O₃ nanocomposites can be exploited in concocting opto-electronic devices.