High Conductivity PEDOT Using Humidity Facilitated Vacuum Vapour Phase Polymerisation

Abstract

The synthesis of high conductivity poly(3,4‐ethylenedioxythiophene) (PEDOT) films using vacuum vapour phase polymerisation is reported. Water vapour is introduced into the chamber and results suggest that it acts as a proton scavenger during polymerisation. Process optimisation leads to PEDOT films that have high conductivity and a blue‐black appearance. Poor quality films have lower conductivity and a characteristic greenish colour. UV‐vis‐NIR spectra show that poor PEDOT films are characterised by higher absorption in the UV‐vis region and an absorption plateau in the NIR region, which suggests an increased level of disrupted conjugation along the polymer backbone or higher oligomer content. Conversely, high quality PEDOT is characterised by an extended NIR absorption tail and lower absorption in the UV‐vis region.magnified image

Effect of Imidazole and Surfactant on the Opto-Electrical Properties of PEDOT Thin Films via Vapor Phase Polymerization

“…Fabretto et al reported the influence of the surfactant PEG-ran-PPG on VPP-based PEDOT films. 27 Similiarly to our results, they confirmed the presence of residual copolymer within the PEDOT film after washing by means of an X-ray photoelectron spectroscopy study.…”

“…15,26 Meanwhile, Fabretto et al suggested the role of water during the VPP process. 27 An appropriate amount of water is necessary for proton scavenging for efficient monomer polymerization. The presence of excess water, however, degrades the quality of the VPP-based PEDOT due to the formation of FTS crystallites.…”

Fabrication of Highly Conductive Pedot Nanofibers

“…Indeed, the mat porosity was estimated to 80 ± 5 % by simple weighting experiment, using a density of 1.6 g.cm -3 previously reported for tosylate-doped PEDOT 9 . By taking into account that the PEDOT nanofibers represent only ~20 % of the sample volume, it can be estimated that individual fibers should have conductivities around 300 S/cm, a value comparable with reported VPP-PEDOT thin films 8 . The electrochemical characterization of the mats was performed under atmosphere conditions, without any special anhydrous or anaerobic condition.…”

“…Figure 3). The characteristic PEDOT spectrum can be observed, with a low absorption in the visible and an increasing absorption after 700 nm, extending in the NIR region, which has been reported as a strong bipolaron absorption, indicating high level of doping 8 . The origin of the high absorption below 500 nm, uncharacteristic of PEDOT, is still under investigation.…”

Vapor phase oxidative synthesis of conjugated polymers and applications

“…86 Fabretto et al suggest that the water is acting as an effective proton scavenger allowing polymerization to proceed. 36 For oCVD polymerization of PEDOT using FeCl 3 as the oxidizing agent, the proposed mechanism of proton scavenging is in the formation of HCl, which is easily evaporated away from the growing polymer chain. 17 The different proton scavenging pathways may be a result of the dissimilar oxidant delivery methods in the VPP and oCVD processes.…”