In-Operando characterizatioN of anti-ambipolar mIxed Conductors

Project Information

IONIC

Grant agreement ID: 101148701

DOI

10.3030/101148701

Project closed

EC signature date 12 March 2024

Start date 1 April 2024

End date 31 March 2026

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 222 727,68

Coordinated by

LINKOPINGS UNIVERSITET
Sweden

Periodic Reporting for period 1 - IONIC (In-Operando characterizatioN of anti-ambipolar mIxed Conductors)

Reporting period: 2024-04-01 to 2026-03-31

Summary of the context and overall objectives of the project

Conjugated organic polymers can be made conductive through charge introduction (doping), enabling flexible organic electronics. A special class of conducting polymers is organic mixed ion–electron conductors (OMIECs), which combine electronic conductivity with the ability to support ionic conduction.
OMIECs are finding applications in advanced circuitry that is mimicking how the brain works, owing to their biocompatibility and similar working principles, but many of the mechanisms underlying their function are currently unknown.
This is especially true for BBL, a ladder-type n-type polymer exhibiting anti-ambipolar behavior, in which charge injection initially increases conductivity, followed by a decrease at higher charge densities.
Since the characteristics of materials such as BBL change drastically while under operation, it is imperative to measure these materials under working conditions (in-operando).
Thereby, the Action "In-Operando characterizatioN of anti-ambipolar mIxed Conductors" is aimed at:
1) unravelling the ion-polymer interactions governing the anti-ambipolar behavior of BBL through novel advanced in-operando characterization,
2) describing the influence of typical polymer parameters (e.g. polymer length, polydispersity) on this behavior, and
3) generalizing the identified mechanisms to other ladder-type polymers.
The results of this project will provide a mechanistic framework for these materials and thereby guide the research and development of n-type ladder-type OMIECs.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project systematically investigated the behavior of the ladder-type polymer BBL and related materials, with a focus on ion–polymer interactions and electrochemical doping mechanisms. The work was conducted through three work packages:
In Work Package 1, advanced operando characterization techniques (including combined EQCM-D with UV–vis and Raman spectroscopy, operando IR spectroscopy, as well as EPR with optical and electrical access) were developed and applied to BBL. Operando THz spectroscopy during the secondment provided an additional piece of the puzzle. These techniques enabled an in-depth understanding of ion–polymer interactions governing BBL's doping response, resulting in a peer-reviewed publication.
In Work Package 2, the scope was refined after discovering that polymer parameters such as chain length primarily influence doping kinetics in BBL rather than steady-state behavior. New experimental methodologies were therefore developed to probe electrochemical (de)doping kinetics, revealing significant and unexpected insights into (de)doping kinetics. These findings are being prepared for publication.
In Work Package 3, several ladder-type polymers structurally related to BBL were studied using operando IR spectroscopy and EQCM-D. The results show that similar ion–polymer interaction mechanisms govern their behavior, although none outperformed BBL. These findings are currently being consolidated for publication.
Overall, the project delivered a detailed mechanistic understanding of ion–polymer interactions and doping kinetics in BBL and related ladder-type polymers, supported by newly developed operando characterization techniques and extensive experiments.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

This project has established a comprehensive mechanistic framework describing the ion–polymer interactions that govern the electrochemical doping and anti-ambipolar behavior of BBL. The results indicate that these mechanisms are likely generalizable to other ladder-type polymers with similar structural motifs. In addition, the project has significantly advanced the understanding of kinetic processes during the electrochemical (de)doping of BBL.
These findings provide a strong scientific foundation for the rational design and optimization of BBL and related organic mixed ion–electron conductors (OMIECs) across a range of applications. The newly developed operando characterization methodologies further represent a valuable toolkit for studying similar materials systems.
Additionally, managing a large collaborative project, disseminating results, and engaging in discussions with many peers in the field, alongside achieving strong scientific output, has been a valuable experience for the MSCA fellow.