Hole-limited electrochemical doping in conjugated polymers.

Simultaneous transport and coupling of ionic and electronic charges is fundamental to electrochemical devices used in energy storage and conversion, neuromorphic computing and bioelectronics. While the mixed conductors enabling these technologies are widely used, the dynamic relationship between ionic and electronic transport is generally poorly understood, hindering the rational design of new materials. In semiconducting electrodes, electrochemical doping is assumed to be limited by motion of ions due to their large mass compared to electrons and/or holes. Here, we show that this basic assumption does not hold for conjugated polymer electrodes. Using operando optical microscopy, we reveal that electrochemical doping speeds in a state-of-the-art polythiophene can be limited by poor hole transport at low doping levels, leading to substantially slower switching speeds than expected. We show that the timescale of hole-limited doping can be controlled by the degree of microstructural heterogeneity, enabling the design of conjugated polymers with improved electrochemical performance.

Description

Acknowledgements: S.T.K. gratefully acknowledges funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement no. 101022365. S.T.K. also acknowledges a graphics processing unit donation from the Nvidia Academic Hardware Grant Program. J.E.M.L. acknowledges funding from the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Award no. EP/R513180/1. R.P. acknowledges funding from an EPSRC Doctoral Prize Fellowship and Clare College, University of Cambridge. C.S. acknowledges financial support from the Royal Commission for the Exhibition of 1851. P.A.M. acknowledges financial support from the EPSRC, UK (grant no. EP/R008779/1), and funding from the European Union's Horizon 2020 Research and Innovation Programme (grant no. 823717, project 'ESTEEM3'). This research was funded in part by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement no. 952911, project BOOSTER, grant agreement no. 862474, project RoLA-FLEX, and grant agreement no. 101007084 CITYSOLAR, as well as EPSRC Project grant nos. EP/T026219/1 and EP/W017091/1. A.R. acknowledges funding from the European Research Council under the European Union's Horizon 2020 Research and Innovation Programme (grant agreement no. 758826). I.M., A.R. and G.G.M. acknowledge support from the Engineering and Physical Sciences Research Council (UK) (grant no. EP/W017091/1). This work was funded by the UKRI. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising.

Funder: University of Cambridge | Clare College, University of Cambridge; doi: https://doi.org/501100001625

Funder: Royal Commission for the Exhibition of 1851; doi: https://doi.org/501100000700

Keywords

3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 3406 Physical Chemistry, 40 Engineering, 4016 Materials Engineering, 7 Affordable and Clean Energy

Journal Title

Nat Mater

Journal ISSN

1476-1122
1476-4660

Volume Title

22

Publisher

Springer Science and Business Media LLC

Publisher DOI

https://doi.org/10.1038/s41563-023-01601-5

Rights

Attribution 4.0 International

Sponsorship

European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (101022365)
EPSRC (EP/W017091/1)
Engineering and Physical Sciences Research Council (EP/R008779/1)
European Research Council (758826)
European Commission Horizon 2020 (H2020) Research Infrastructures (RI) (823717)

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