PEDOT/WO₃ Hybrid Nanofiber Architectures for High Performance Electrochromic Devices

Abstract

This study focuses on the electrochromic device (ECD) applications of poly(3,4‐ethylenedioxythiophene)/tungsten oxide (PEDOT/WO3) hybrid nanofibers prepared via electrospinning method. Nanoporous WO3 films were initially electrosynthesized on Pt sheet. The PEDOT layer was electropolymerized onto the entire surface of the WO3 nanoporous host framework in the presence of different ionic liquids: 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIMBF4), 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6), 1‐butyl‐ 3‐methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). The morphological features and elemental surface characterization of hybride nanofibers were monitored by scanning electron microscopy and energy dispersive X‐ray spectroscopy. ECDs changed color reversibly from transparent to light brown by switching from +3 V to −3 V. It was found that the highest optical modulation of 47.89 % and maximum coloration efficiency of 363.72 cm2/C is achieved for PEDOT/WO3/BMIMPF6 based electrochromic device. Hybrid nanofibers exhibited excellent long term stability even after 1000 chronoamperometric cycles. This work could not only push forward the facile preparation of PEDOT/WO3 nanofibers but also represent, for the first time, the possibility that the hybrid nanofibers could be a promising material for the highly efficient ECDs.

Electrochromic Properties of Electrospun Fibers Based on Bis‐Thiomethylcyclohexanone Derivatives

“…The optical‐switching time of the ECD based on CPPTMC‐ PMMA hybrid fibers due to its molecular structure and morphology is faster when compared to the ECD based on PPTMC‐ PMMA hybrid fibers. This fast response can be related to ion intercalation kinetics . In EDCs, the intercalation/deintercalation of electrons and transportation of counter ions takes place simultaneously under an applied electric field, and this is directly related to the electrochromic properties of the material …”

“…As is well known, the electrochromism of anhydrous tungsten oxide, some tungsten oxide‐hydrates, and their composites formed with the polymers is based on intercalation/deintercalation of positive ions (H + , Li + ,etc.) and electrons into the structure of materials during the electrochromic process . Undoubtedly, the intercalation/deintercalation of electrons and ions are negligibly affected by the electronic structure of materials .…”

“…Undoubtedly, the intercalation/deintercalation of electrons and ions are negligibly affected by the electronic structure of materials . Electrospun fibers with unique features such as large surface area, high length/diameter ratio and high porosity, they have been used to improve EC modulation and switching speed owing to the fast charge transport through the electrodes . Herein, we specifically examined the color switching speeds and the redox activities of the ECDs based on PPTMC‐ PMMA and CPPTMC‐ PMMA hybrid fibers.…”

“…This fast response can be related to ion intercalation kinetics. [46,50] In EDCs, the intercalation/ deintercalation of electrons and transportation of counter ions takes place simultaneously under an applied electric field, and this is directly related to the electrochromic properties of the material. [51] As is well known, the electrochromism of anhydrous tungsten oxide, some tungsten oxide-hydrates, and their composites formed with the polymers is based on intercalation/deintercalation of positive ions (H + , Li + ,etc.)…”

Electrochromic properties of some bis‐chalcone derivatives‐based nanofibers

“…In recent years, conducting polymer‐based hybrid materials have become a subject of growing interest due to its nanoscale porosity for diverse electrochemical applications such as energy storage, electrochromic devices (ECDs) . Electrochromic (EC) materials exhibit a reversible color change upon reduction or oxidation in accompaniment with an electron‐transfer reaction when a voltage is applied to them .…”