Synergetic Effect of Perfluorooctanoic Acid on the Preparation of Poly(3,4‐ethylenedioxythiophene): Lignosulfonate Aqueous Dispersions with High Film Conductivity

Abstract

Developing poly(3,4‐ethylenedioxythiophene) (PEDOT) conducting polymers (CPs) aqueous dispersions with high film conductivity is an attractive task in scientific and industrial communities. Herein, we proposed to apply small molecular perfluorooctanoic acid (PFA) as assistant dopant to cooperate with major polymeric dopant of lignosulfonate (LGS) to prepare PEDOT aqueous dispersions together. Through optimizing the usage amount of PFA, a high film conductivity of 0.1255 S⋅cm−1 was obtained. In contrast, the film conductivity of the CP prepared without PFA was only 0.0228 S⋅cm−1. By lucubrating the structure of CPs, we found that PFA is capable of promoting the polymerization, doping and aggregation of PEDOT in the preparation process of PEDOT:LGS CP and the conductivity enhancement can be attributed to the enhancement of molecular weight, doping degree and aggregation of PEDOT. Moreover, the other physical‐chemical properties of PEDOT:LGS CPs including transmittance, work function and waterproofness were not obviously affected by PFA. This facile strategy based on physical mixing of small molecular and polymeric dopants may opens up a new window for the preparation of high performance CPs aqueous dispersions.

Oxidative Photopolymerization of 3,4‐Ethylenedioxythiophene (EDOT) via Graphitic Carbon Nitride: A Modular Toolbox for Attaining PEDOT**

“…After the oxidative photopolymerization of colorless EDOT, the resulting liquid oligo‐EDOT (after separation of g‐CN) undergoes significant darkening compared to EDOT. Generally, pitch black color of oligo‐EDOT arises from its fully oxidized state, however a photoredox synthesis cannot donate a full oxidation, so a linear oligo‐EDOT with a moderate oxidation is obtained in the present case In order to get more insight about eventual molecular weight, UV‐vis spectra were applied as inspired by the literature (Figure S4a) [36–38] . The significant bathochromic shift on UV‐vis spectrum from 450 nm to 650 nm is explicated as a sign of an increased molecular weight of EDOT based on extended conjugated units.…”

Template molecular weight-dependent PEDOT surface energy: impact on the photovoltaic performance of bulk-heterojunctions

“…30 This is because the band gap between the highest occupied molecular (HOMO) and lowest unoccupied molecular orbitals (LUMO) of polythiophene derivatives usually decreases with the elongation of the polymer chain length, leading to a gradual red-shi in the absorption spectrum. 10,[31][32][33] Prior to the spectral tests, chemical dedoping experiments were conducted to fully reduce the synthesized PEDOTs from the oxidized (doped) to neutral (dedoped) states with the aim of eliminating the polaronic/bipolaronic orbitals. 34 Fig.…”