Harnessing Plasmonic Iodine Interactions in Molybdenum Oxide Iodide–Poly(N-Methylpyrrole) Nanocomposites for Advanced Optoelectronic and Solar Applications

Harnessing plasmonic interactions within iodide-modified frameworks offers an unconventional pathway for advancing next-generation optoelectronic and solar technologies. Here, we report the rational design of a molybdenum oxide iodide/iodine–poly(N-methylpyrrole) nanorod composite (Mo(VI)OI/I₂-PNMP), in which plasmon-active iodide species are intercalated within a conductive polymer matrix to establish synergistic light–matter coupling. The nanocomposite displays a distinctive rough-surfaced nanorod morphology (∼100 × 500 nm) with crystalline domains of ~11 nm, enabling strong interfacial charge delocalization. Optical analysis reveals a direct bandgap of 1.96 eV, optimally positioned for solar absorption, while the iodide component introduces localized surface plasmon resonances that enhance charge carrier excitation. Integration of Mo(VI)OI/I₂-PNMP with polypyrrole yields a hybrid thin-film device exhibiting efficient photovoltaic operation, with an open-circuit voltage of 0.45 V and photocurrent densities of 0.03 mA·cm⁻² (light) versus 0.005 mA·cm⁻² (dark). The device further demonstrates broadband photodetection, achieving photoresponsivity of 0.26 and 0.18 mA/W at photon energies of 3.6 and 2.3 eV, respectively, alongside detectivity up to 0.6 × 10⁸ Jones. These results establish iodide-driven plasmonic modulation as a powerful tool for tailoring optoelectronic responses in hybrid polymer–oxide systems. Beyond performance metrics, the scalable synthesis, low-cost processing, and multifunctionality of the Mo(VI)OI/I₂-PNMP/PPy architecture point toward transformative opportunities in integrated solar harvesting and advanced photodetection platforms.