Optimal array alignment to deliver high performance in flexible conducting polymer-based thermoelectric devices

Flexible thermoelectric devices (F-TEDs) show great potentials to be applied in curved surface for power generation by harvesting low-grade energy from human body and other heat sources. However, their power generation efficiency is constrained by both unsatisfactory constituent materials performance and immature device design. Here, we used an optimal alignment of vertically-aligned poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) arrays to assemble a 2.7 x 3.2 cm(2) F-TEDs, exhibiting a maximum power output of 10.5 mu W. Such a high performance can be ascribed to the out standing power factor of 198 mu W-1 K-2 by the synergetic effect of both high charge mobility and optimal oxidation level and the optimized array alignment that maximizes the temperature difference utilization ratio across the TE legs. Particularly, optimized leg distance of 6 mm and leg length of 12 mm are determined to realize a high temperature difference utilization ratio of over 95% and a record-high output power density of 1.21 mu W cm(-2) under a temperature difference of 30 K. Further, reliable bending (1000 cycles) and stability (240 h) tests indicate the outstanding mechanical robustness and environmental stability of the developed F-TEDs. This study indicates our reasonable device design concept and facile material treatment techniques secure high-performance F-TEDs, serving as a reference for other flexible energy harvesting devices with wide practical applications. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study demonstrates the successful fabrication of a high-performance flexible thermoelectric device (F-TEDs) by optimizing the assembly of vertically-aligned poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) arrays. The optimized device design and material treatment techniques ensure the high performance, mechanical robustness, and environmental stability of the F-TEDs.