Enhanced thermoelectric performance of poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) with long‐term humidity stability via sequential treatment with trifluoroacetic acid

This paper reports a range of effective sequential chemical processes to enhance the thermoelectric performance of conducting poly(3,4‐ethylenedioxythiophene) films doped with poly(styrene sulfonate) anions (PEDOT:PSS). The electrical conductivity of the PEDOT:PSS films was significantly increased from 0.33 to 3748 S cm −1 after a series of sequential treatments with trifluoroacetic acid (TFA) while the Seebeck coefficient and thermal conductivity were slightly reduced from 17.5 ± 1.2 to 16.0 ± 1.1 μV K −1 and 0.537 to 0.415 W m –1 K −1 for the pristine film and treated film, respectively, leading to a significant improvement in power factor up to 97.1 ± 5.4 μW m –1 K −2 . More importantly, around 80% of the electrical conductivity and Seebeck coefficient was retained after 20 days for these TFA‐treated PEDOT:PSS films, revealing the potential for real thermoelectric applications.