Dual‐Interfacial Engineering of PEDOT:PSS/Narrow‐Bandgap Semiconductor Nanowire Composite Fibers for High‐Performance Thermoelectric Applications

ABSTRACT Organic/inorganic composite thermoelectric (TE) fibers are attracting increasing attention in wearable electronics due to their distinctive combination of flexibility and thermal‐to‐electric energy conversion capability. However, the TE properties of most composite fibers remain unsatisfactory, limiting their widespread applications. High‐performance poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/tellurium (Te) @polyaniline (PANI) composite fibers with an engineered dual‐interface structure are fabricated by extending our previously proposed dual‐interfacial engineering strategy to narrow‐bandgap semiconductor nanowires. The introduction of an intermediate PANI layer between Te and PEDOT:PSS not only suppresses the agglomeration of Te nanowires, but also, for the first time in such systems, establishes Te─N coordination bonds alongside hydrogen bonding and π – π stacking. This unique interfacial synergy enables tunable dual interfacial energy barriers and a pronounced energy filtering effect. Consequently, the optimized composite fiber achieves a remarkable power factor of 552.9 µW m −1 K −2 , which is the highest value reported for PEDOT:PSS‐based composite TE fibers. Finally, the composite fibers are developed into fibrous TE generators and self‐powered temperature sensors. Finite element analysis simulations are also employed to achieve a rational design in device configuration. This study validates the dual‐interfacial engineering generality and unveils new interfacial chemistry in organic/narrow‐bandgap semiconductor hybrids, opening up an avenue for high‐performance fiber‐type TE materials.