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Ladder-type structures can impart exceptional stability to polymeric electronic materials. This article introduces a new class of conductive polymers featuring a fully ladder-type backbone. A judicious molecular design strategy enables the synthesis of a low-defect ladder polymer, which can be efficiently oxidized and acid-doped to achieve its conductive state. The structural elucidation of this polymer and the characterization of its open-shell nature are facilitated with the assistance of studies on small molecular models. An autonomous robotic system is used to optimize the conductivity of the polymer thin film, achieving over 7 mS cm^−1. Impressively, this polymer demonstrates unparalleled stability in strong acid and under harsh UV-irradiation, significantly surpassing commercial benchmarks like PEDOT:PSS and polyaniline. Moreover, it displays superior durability across numerous redox cycles as the active material in an electrochromic device and as the pseudocapacitive material in a supercapacitor device. This work provides structural design guidance for durable conductive polymers for long-term device operation.
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Extraordinary electrochemical stability and extended polaron delocalization of ladder-type polyaniline-analogous polymers
Electrochemical stability and delocalization of states critically impact the functions and practical applications of electronically active polymers. Incorporation of a ladder-type constitution into these polymers represents a promising strategy to enhance the aforementioned properties from a fundamental structural perspective. A series of ladder-type polyaniline-analogous polymers are designed as models to test this hypothesis and are synthesized through a facile and scalable route. Chemical and electrochemical interconversions between the fully oxidized pernigraniline state and the fully reduced leucoemeraldine state are both achieved in a highly reversible and robust manner. The protonated pernigraniline form of the ladder polymer exhibits unprecedented electrochemical stability under highly acidic and oxidative conditions, enabling the access of a near-infrared light-absorbing material with extended polaron delocalization in the solid-state. An electrochromic device composed of this ladder polymer shows distinct switching between UV- and near-infrared-absorbing states with a remarkable cyclability, meanwhile tolerating a wide operating window of 4 volts. Taken together, these results demonstrate the principle of employing a ladder-type backbone constitution to impart superior electrochemical properties into electronically active polymers.
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- Award ID(s):
- 1808779
- PAR ID:
- 10309558
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 11
- Issue:
- 47
- ISSN:
- 2041-6520
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0SC03348K
