Efficient enhancement of the thermoelectric performance of vapor phase polymerized poly(3,4‐ethylenedioxythiophene) films with poly(ethyleneimine)

Abstract

Tuning the molecular rearrangement and oxidation level has been proven to be effective strategies for optimizing the thermoelectric (TE) performance of PEDOT. It is difficult to achieve these effects simultaneously via a one‐step process, however. In this work, we combined vapor phase polymerization (VPP) and H2SO4 post‐treatment to obtain a highly conductive PEDOT film. A novel strategy using polyethylenemine (PEI) as an effective reducing agent was employed to enhance the thermopower of the PEDOT film. Grazing‐Incidence Wide‐Angle X‐ray Scattering analysis and the changes in the oxidation level allow us to elucidate the role of PEI and its transport mechanism. It is demonstrated that the thermopower of well‐ordered crystallites in the PEDOT film significantly increases more than five times (from 11 to 59 μV K−1) by the PEI‐DMF solution immersion process, while the electrical conductivity is maintained at 100 S cm−1. The promising method connecting VPP, H2SO4, and PEI shows great potential for effectively tuning the thermopower of organic TE materials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 257–265

Robust PEDOT:PSS Wet‐Spun Fibers for Thermoelectric Textiles

“…A number of previous publications indicate that the power factor of PEDOT:tosylate can be improved by chemical dedoping with tetrakis(dimethylamino)ethylene (TDAE) or polyethyleneimine (PEI) 38,39. Inspired by these reports and the good aqueous stability of our PEDOT:PSS fibers, we studied their thermoelectric properties upon dedoping through the immersion in aqueous solutions of PEI ( Figure a).…”

Modulating Carrier Type for Enhanced Thermoelectric Performance of Single-Walled Carbon Nanotubes/Polyethyleneimine Composites

“…The increase in electrical conductivity might be attributed to the formation of an interconnected SWCNT network, due to improved dispersion and film formation prompted by the addition of PEI and Nafion, which facilitates effective carrier transport. Since PEI is an electrical insulator, when a large amount of PEI is coated on the surface of the SWCNTs, it may prevent carrier transport across the junctions between the SWCNTs, resulting in a reduction in electrical conductivity [37]. Amine-rich PEI was adsorbed onto the surface of the SWCNTs where it acts as an electron donor, which changed the carrier type of the SWCNT/PEI composites from p - to n -type when high amounts of PEI were used (Figure 5b) [22,38].…”

Advances in Efficient Polymerization of Solid-State Trithiophenes for Organic Thermoelectric Thin-Film

“…Figure D show the two-dimensional (2D) out-of-plane GIWAXS pattern of P­(BisEDOT-Th) by spin-spray coating polymerization method. As we know, the PEDOT molecules are allowed to have a more ordered structure by VPP technology related to the electronic transport property. ,, We expect that the spin-spray coating polymerization method can also achieve a polymer film with an ordered structure like the PEDOT obtained by VPP. Nevertheless, the packing of P­(BisEDOT-Th) do not display the apparent lamellar and ordered structure according to Figure D. , One can observe the similar diffractograms for the P­(BisEDOT-ThR) in Figure S5 and P­(BisEDOT-OctTh) in Figure E.…”

“…For conducting polymers, the existing methods including oxidative chemical vapor deposition (oCVD) and vapor phase polymerization (VPP) have been confirmed to be able to obtain uniform conductive films by one step in order to avoid the poor solubility during solution-based polymerization. , These methods have been widely gained acceptance due to the high-quality thin-films. ,, For oCVD, it is usually necessary to simultaneously vaporize the precursor and oxidant during the process of film deposition, however, which typically involves complex mechanical driving forces, resulting in increased film preparation costs . By contrast, though VPP technology has an easy-to-use device with its simplicity and robustness, it requires gasification of precursor enabling the substrate coated with oxidants to achieve a full and uniform contact. , It has been limited for few of organic precursors such as aniline, pyrrole, 3,4-ethylenedioxythiophene (EDOT) and so on with the typical feature of low saturated vapor pressure. − Nevertheless, the organic electron materials with a good electronic/optical property generally require a complex or expectant chemical structure and a complicate polymerization. , Moreover, the resultant polymers have the insolubility or poor processability in common organic solvents. Therefore, it is desirable to develop a new approach for the fabrication of uniform polymer thin-films by a much simpler operation referring to the polymerization of precursors with the more complex structure.…”