Tuning Electrical, Mechanical, and Structural Properties of PEDOT : PSS Films Through the Surfactant and High Boiling Solvent Dual Modification

In this study, we investigated a dual modification strategy using N,N‐dimethylformamide (DMF) and anionic surfactants such as sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) to cooperatively optimize charge transport, morphology, and mechanical stability in free‐standing poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films. Systematic variation of DMF concentration (0.26–4.04 wt%) revealed that only DMF treatment without surfactant enhanced electrical conductivity to 545 Scm −1 and power factor (PF) to 26.1 μW m −1 K −2 , resulting in a 33% reduction in the PSS:PEDOT ratio and improved π–π stacking reduced from 3.46 to 3.41 Å. Incorporation of SDS further balanced high conductivity (447 Scm −1 ) with exceptional elongation at break (51.3%), overcoming the traditional trade‐off between electrical performance and flexibility. SDBS‐modified films exhibited enhanced PEDOT‐rich morphology and strong optical absorption but showed moderate Seebeck suppression due to elevated carrier density. Thermal conductivity reduction from 0.30 to 0.16 Wm −1 K −1 yielded a peak ZT of 0.035 for PEDOT:PSS‐based films. Complementary XRD, XPS, SEM‐EDS, and carrier density and hole mobility analyses confirmed that solvent‐surfactant combined effect promotes PSS reduction, chain ordering, and π–π stacking interaction, correlating structural evolution with thermoelectric performance. This efficient, scalable approach produces mechanically robust, high‐conductivity PEDOT:PSS films, improving them for next‐generation flexible and wearable thermoelectric energy‐harvesting devices.