Enhanced thermoelectric performance of PEDOT: PSS films via ionic liquid post-treatment

Abstract

Thermoelectric (TE) energy harvesting can effectively convert waste heat into electricity, which is a crucial technology to solve energy concerns. As a promising candidate for energy conversion, poly(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) has gained significant attention owing to its easy doping, high transparency, and solution processability. However, the TE performance of PEDOT:PSS still needs to be further enhanced. Herein, different approaches have been applied for tuning the TE properties: (i) direct dipping PEDOT:PSS thin films in ionic liquid; (ii) post-treatment of the films with concentrated sulfuric acid (H2SO4), and then dipping in ionic liquid. Besides, the same bis(trifluoromethanesulfonyl)amide (TFSI) anion and different cation salts, including 1-ethyl-3-methylimidazolium (EMIM+) and lithium (Li+), are selected to study the influence of varying cation types on the TE properties of PEDOT:PSS. The Seebeck coefficient and electrical conductivity of the PEDOT:PSS film treated with H2SO4EMIM:TFSI increase simultaneously, and the resulting maximum power factor is 46.7 μW⋅m−1⋅K–2, which may be attributed to the ionic liquid facilitating the rearrangement of the molecular chain of PEDOT. The work provides a reference for the development of organic films with high TE properties.

Stretchable PEDOT:PSS/Li-TFSI/XSB Composite Films for Electromagnetic Interference Shielding

“…The PEDOT:PSS dispersion after evaporating water does not form a flat film on the Teflon mold. However, the film-forming ability is acquired after Li-TFSI doping, and the formed flat films have good toughness. , The doping causes a morphological rearrangement in favor of PEDOT chain packing, as demonstrated by a newly formed X-ray diffraction (XRD) peak at a diffraction angle of 12.12° and sharpened intrinsic peaks at 18.08 and 25.88° (Figure S6). , The intrinsic peaks also appear in the pure PEDOT:PSS film.…”

Boosting the Performance of PEDOT:PSS Based Electronics Via Ionic Liquids

“…The variance in the amplitude of polarization transitions indicated that ILs featuring smaller‐sized cations exhibited a more potent reducing effect. [ 100 ] A substantial improvement in conductivity was realized through intensive mixing of PEDOT:PSS solutions with IL containing bis(trifluoromethylsulfonyl)imide (TFSI) anions. [ 87 ] By altering the cation from (2‐(2‐ethoxyethoxy)ethyl)triethylphosphonium (P2EOE) (conductivity: ≈ 8 S cm −1 ) and (2‐ethoxyethyl)triethylphosphonium (PEOE) (conductivity: ≈ 16 S cm −1 ) to EMIM (conductivity: ≈ 220 S cm −1 ) and finally to Li + (conductivity: ≈ 420 S cm −1 ), the most effective among the series, there was an enhancement in crystalline order and p‐doping level of PEDOT, leading to higher conductivity.…”