Vapor phase polymerization of Ag QD-embedded PEDOT film with enhanced thermoelectric and antibacterial properties

Nonferric oxidant precursors have the unique advantage of directly polymerizing poly(3,4-ethylenedioxythiophene) (PEDOT)-inorganic composites. However, due to limited solubility and unmatched oxidation potentials, most oxidants only produce powders or porous materials. To obtain high-quality films with improved homogeneity and controllable particle sizes, the oxidants should be adaptable to high-standard PEDOT film fabrication techniques such as vapor phase polymerization (VPP). In this work, we discovered for the first time a nonferric metal salt suitable for the VPP process. With the addition of an Fe(III) salt to stabilize the reaction and adjust the oxidant ratio, micron-thick antibacterial S-PEDOT-Ag quantum dot (QD) composite films with tunable Ag wt% can be synthesized in one facile step. With a low Ag loading of ~0.2 wt%, the film exhibited an optimized power factor of 63.1 μW/mK², which is among the highest values thus far reported for PEDOT-metal composites. Increase of the Ag(I) concentration in the precursor to a certain level may lead to minor decomposition of the polymer followed by the formation of Ag₂S particles.