Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

Abstract

The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm−1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m−1 K−2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat.

High-performance shape-engineerable thermoelectric painting

“…One readily available solution to settling down the aforementioned issues would be to secure a way to maximizing the flexibility in the shape and dimension control of TE materials during the forming stage, where the well-established printing technology would best-serve the purpose14151617181920212223. However, this printing-based technology has faced at least two major challenges.…”

“…However, this printing-based technology has faced at least two major challenges. One is the poor functional properties due to the unavoidable organic-conducting binders in the inks for electrical interconnection among TE particles at the expense of TE properties202122. Although the properties can be enhanced by high temperature processing instead of using organic binders, such enhancement is quite limited; for example, the state of the art utilizing a printing technique for TE materials deposited on a glass fabric achieved ZT values of 0.35 (n-type) and 0.27 (p-type)23 which are at most 20–40% of the commonly reported values from the conventional processing2 even with the sintering temperature of as high as 530 °C close to the melting point of the TE materials.…”

Thermoelectric properties of poly (3,4-ethylenedioxy thiophene)/poly (sulfonic acid diphenyl aniline) composites synthesized in the absence and presence of magnetic field

“…At first, Kim et al succeeded in the conductivity enhancement of PEDOT:PSS by adding dimethyl sulfoxide or dimethylformamide into PEDOT: PSS aqueous solution [4]. Later, polar organic solvents such as alcohols, ethylene glycol, N-methyl pyrrolidone, sorbitol [5], some inorganic acids [6], and some organic salt solutions [7] were used as secondary dopants to achieve a conductivity enhancement by up to 4 orders of magnitudes [8]. This remarkable result is thought to be due to the PEDOT chain alignment, depletion of insulating PSS shell and growth of the PEDOT domains.…”

“…Bae et al reported significant enhancement of the electrical conductivity of PEDOT:PSS from 787.99 to 4839.92 S cm −1 by simple chemical treatment with H 2 SO 4 [6]. The increase was attributed to the increasing carrier concentration and improved crystallinity of PEDOT due to the removal of PSS, which induces the formation of a more crystalline structure.…”

Copper Sulfides: Earth‐Abundant and Low‐Cost Thermoelectric Materials

“…These materials have recently been used to develop organic thermoelectric materials, which are promising for wearable heating and cooling devices, working at near‐room temperatures. One of the widely studied organic material is PEDOT:PSS, which is a special compound that is well studied for thermoelectric applications . Other important organic/polymers that have been studied to date are conducting polymers, such as polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh) and some of their derivatives, and organic semiconductors such as pentacene …”