Enhancing the Thermoelectric Properties of Conjugated Polymers by Suppressing Dopant‐Induced Disorder

Abstract Doping is a crucial strategy to enhance the performance of various organic electronic devices. However, in many cases, the random distribution of dopants in conjugated polymers leads to the disruption of the polymer microstructure, severely constraining the achievable performance of electronic devices. Here, we show that by ion‐exchange doping polythiophene‐based P[(3HT) 1‐x ‐stat‐(T) x ] (x = 0 (P1), 0.12 (P2), 0.24 (P3), and 0.36 (P4)), remarkably high electrical conductivity of > 400 S cm −1 and power factor of >16 μW m −1 K −2 were achieved for the random copolymer P3, ranking it among highest ever reported for unaligned P3HT‐based films, significantly higher than that of P1(< 40 S cm −1, < 4 μW m −1 K −2 ). Although both polymers exhibit comparable field‐effect transistor hole mobilities of ca. 0.1 cm 2 V −1 s −1 in the pristine state, after doping, Hall effect measurements indicate that P3 exhibits a large Hall mobility up to 1.2 cm 2 V −1 s −1 , significantly outperforming that of P1 (0.06 cm 2 V −1 s −1 ). GIWAXS measurement determined that the in‐plane π‐π stacking distance of doped P3 is 3.44Å, distinctly shorter than that of doped P1 (3.68Å). Our findings contribute to resolving the long‐standing dopant‐induced‐disorder issues in P3HT and serve as an example for achieving fast charge transport in highly doped polymers for efficient electronics. This article is protected by copyright. All rights reserved