Processable Thiophene‐Based Polymers with Tailored Electronic Properties and their Application in Solid‐State Electrochromic Devices Using Nanoparticle Films

Abstract

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 CHCH or CH2CH2 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.

Ladder-like Polymer Brushes Containing Conjugated Poly(Propylenedioxythiophene) Chains

“…Polythiophenes, one of the most important classes of conjugated polymers, have been extensively investigated for their great optical properties [ 16 , 17 , 18 , 19 ]. Indeed, polythiophene and its derivatives are typically characterized by a relatively stable conductivity level and optical transparency, which are relevant for various applications [ 20 ].…”

Multi-objective goal-directed optimization of de novo stable organic radicals for aqueous redox flow batteries

“…This is in correlation with the increasing use of similar molecules in organic bioelectronic devices. Previous work has shown that the electrical properties of thiophenes can be tuned by introducing alkoxy substituents 63,64 . Their enrichment among the chemically synthesizable radicals may also be due to the availability of reaction templates for this chemistry, as only 104 of the 232 DFT-confirmed RL candidates possess this functional group.…”

Synthetic strategies, molecular engineering and applications of semiconducting polymers based on diarylethylene units in electronic devices

“…Thiophene-based conjugated polymers have made remarkable progress, which is attributed to their unique semiconducting properties and effective charge carrier transport properties. 60,95,96 Polythiophene was first discovered to be a highly conductive polymeric material but had poor solubility. However, poly(3-hexylthiophene) (P3HT) has attracted considerable attention due to the introduction of hexyl side chains to improve its solution processability.…”