Nanocorrugation-Enabled Surface Plasmon Resonances in Organic Conductive Polymer Films for Tunable Soft Photonic Devices

The emergence of conductive polymers such as PEDOT:Sulf as alternatives to noble metals promises a new class of optoelectronic materials with mechanical flexibility, tunable optical properties, and a low-cost fabrication process for photonic applications. However, their inherently low free-carrier charge densities and mobilities hinder strong and spectrally tunable plasmon resonances. Here, we use full-wave 3D finite-element simulations to show that nanoscale corrugation-induced deformation in conductive PEDOT:Sulf thin films enables the excitation and tunable modulation of all-organic broadband plasmonic resonances from the visible to the near-infrared spectral range through engineered subwavelength grooves and ridges. We show that nanoscale corrugations act as a distributed phase-matching interface, thereby enabling strong far-field coupling to localized and hybridized plasmonic modes. The nanocorrugated structure exhibits absorbance intensity up to ∼0.7 and near-field enhancement up to ∼502 due to curvature-induced modal confinement and momentum matching. Furthermore, we show that the nanocorrugated polymer platform exhibits a relatively high refractive index sensitivity of ∼850 nm/RIU in the near field, confirming its strong evanescent field overlap and suitability for biochemical and environmental sensing. Our simulations demonstrate that nanostructured PEDOT:Sulf can serve as a tunable, all-organic plasmonic platform, offering a compelling path toward soft-matter nanophotonics, infrared optoelectronics, flexible biosensors, and reconfigurable photonic devices based on conducting polymers.