Comparative analysis of optoelectronic and structural characteristics in electrochemically synthesized hybrid-nanocomposites based on PANI-CSA/metal oxide nanoparticles

The strategic integration of conductive polymers with transition metal oxide nanoparticles (NPs) offers a promising route to engineer multifunctional nanocomposite systems with tailored optoelectronic properties. In this work, we report the electrochemical synthesis and detailed characterization of PANI-CSA-based hybrid nanocomposites embedded with 12 wt% of CoFe₂O₄, Co₃O₄, and Fe₂O₃ nanoparticles. Thin films were deposited via in situ electrodeposition onto ITO-glass substrates, enabling precise control over composition and morphology. Comprehensive optical analysis via UV–Vis spectroscopy revealed NP-induced modulation of key optical parameters, including enhanced absorption, modified refractive indices, and tunable optical bandgaps. Tauc plot analysis indicated systematic bandgap shifts ranging from 3.48 to 3.61 eV, while Urbach energy trends reflected variations in structural disorder. XRD confirmed increased crystalline and the formation of larger crystallites upon nanoparticle incorporation, consistent with interfacial ordering effects. FTIR spectra substantiated strong molecular interactions between PANI chains and metal oxide surfaces, while SEM micrographs exhibited dense fibrous morphologies supporting effective charge transport pathways. Electrical conductivity measurements, performed via a four-point probe, demonstrated high conductivity (77.3–79.9 S cm⁻¹), with the Co₃O₄-based system exhibiting superior performance, attributable to enhanced crystallinity and potential p-type doping effects. Collectively, these results highlight the efficacy of metal oxide NPs as secondary dopants in modulating the optoelectronic response of PANI-CSA, positioning these hybrid films as viable candidates for advanced optoelectronic applications, including optical sensors and flexible electronic devices.