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Processable Thiophene‐Based Polymers with Tailored Electronic Properties and their Application in Solid‐State Electrochromic Devices Using Nanoparticle Films
Author(s) -
Moreira Tiago,
Maria Francesca Di,
Zangoli Mattia,
Fabiano Eduardo,
Manet Ilse,
Mazzaro Raffaello,
Morandi Vittorio,
Marinelli Martina,
Gigli Giuseppe,
Parola António Jorge,
Laia César A. T.,
Barbarella Giovanna
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202100166
Subject(s) - electrochromism , materials science , thiophene , electrochromic devices , polymer , nanoparticle , nanotechnology , photochemistry , chemical engineering , optoelectronics , organic chemistry , electrode , chemistry , composite material , engineering
The development of semiconductor polymers for electronic applications requires tailored synthetic strategies to obtain materials with tunable electronic properties and morphology to enhance their properties. Towards this goal, here is reported the expedient synthesis of a novel class of thiophene‐based electrochromic polymers, processable in organic solvents and as nanoparticles (NPs) in water. Their characterization and application in flexible solid‐state electrochromic devices (ECDs) are described. All polymers have a repeat unit made of the same linear thienyl–phenyl–thienyl–thienyl fragment. The tuning of the electro‐optical properties is achieved by introducing alkyl or alkoxy substituents in thiophene and/or by the presence of either CHCH or CH 2 CH 2 linkers connecting the repeat units and acting as conjugation modulators. The ECDs display a bright yellow or red/magenta color in the neutral state and dark blue in the oxidized state. Redox potentials, color contrast, switching time, and stability of the devices are reported, and it is demonstrated that the use of NPs films spray‐coated from water instead of cast films from chloroform significantly improves their performance. Density functional theory calculations allow to elucidate the relationship between polymer structure and electrochromic properties and shed light on electronic structure changes upon oxidation, in agreement with spectroelectrochemistry.