Highly stretchable organic thermoelectrics with an enhanced power factor due to extended localization length

Wearable electronics, as a new form of ubiquitous technology, require a sustainable self-powering system with an enhanced mechanical durability. In this report, we demonstrate a conducting polymer based stretchable thermoelectric performance with a synergetic effect of an enhanced power factor due to electron delocalization. The fluorosurfactant treatment of poly(3,4-ethylene dioxythiophene):poly(styrenesulphonate) (PEDOT:PSS) films induced a significant dedoping effect with an enhanced Seebeck coefficient and a morphological change into an elongated lamellar structure. Such structural transformation led to a reduced transport dimensionality with strongly extended electron delocalization yielding a simultaneous enhancement of the electron mobility and the Seebeck coefficient, which produced an improved thermoelectric power factor. Most notably, the mechanical durability of the PEDOT:PSS film was greatly improved tolerating up to a 60% static strain and over several hundred cycles of 50% strain. The demonstrated concomitant enhancement of the mechanical stretchability and thermoelectric performance inspires a promising approach for improving shape-adjustable self-powering devices.