One-dimensional variable range charge carrier hopping in polyaniline–tungsten oxide nanocomposite-based hydrazine chemiresistor

Low-temperature direct current charge transport mechanism of charge carriers in polyaniline–tungsten oxide (PAN-WO₃) nanocomposite has been investigated. Charge transport in pristine PAN was found to govern by Mott’s three-dimensional variable range hopping (3-D VRH) model. However, the inclusion of WO₃ in nanocomposite shifts the dimension of hopping from 3-D to 1-D. The room-temperature conductivity of PAN-WO₃ nanocomposite (5.55 × 10^–3 S/cm) was also found to be enhanced compared to pristine PAN (1.27 × 10^–5 S/cm). The reasons for crossover in hopping dimensionality and enhanced conductivity of PAN-WO₃ nanocomposite have been explained in terms of Mott’s parameters, i.e., small hopping radius, lower hopping energy, high inter-chain distance, and prominent intra-chain transport. Furthermore, PAN-WO₃ exhibited enhanced reversible sensing behaviour (27%) towards 10 parts per million of hydrazine at room temperature compared to that of pristine PAN (12%). Enhanced sensing characteristics of PAN-WO₃ nanocomposite can be attributed to its higher conductivity and prominent intra-chain unidirectional charge transport. Present communication opens a new window for energy-saving, eco-friendly, cost-effective, recoverable and reproducible, easily processable and efficient PAN-WO₃ nanocomposite-based hydrazine detecting device.