Organic mixed ionic–electronic conductors


Materials that efficiently transport and couple ionic and electronic charge are key to advancing a host of technological developments for next-generation bioelectronic, optoelectronic and energy storage devices. Here we highlight key progress in the design and study of organic mixed ionic–electronic conductors (OMIECs), a diverse family of soft synthetically tunable mixed conductors. Across applications, the same interrelated fundamental physical processes dictate OMIEC properties and determine device performance. Owing to ionic and electronic interactions and coupled transport properties, OMIECs demand special understanding beyond knowledge derived from the study of organic thin films and membranes meant to support either electronic or ionic processes only. We address seemingly conflicting views and terminology regarding charging processes in these materials, and highlight recent approaches that extend fundamental understanding and contribute to the advancement of materials. Further progress is predicated on multimodal and multi-scale approaches to overcome lingering barriers to OMIEC design and implementation.

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Fig. 1: Material classes of OMIECs.
Fig. 2: Processes in OMIECs.
Fig. 3: Typical configurations of OMIEC-based devices.
Fig. 4: Understanding interrelations in OMIECs.
Fig. 5: The profound influence of electrolyte on film structural characteristics.
Fig. 6: Multi-scale microstructure and associated techniques for studying OMIECs.


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B.P. and J.R. gratefully acknowledge support from the National Science Foundation grant no. NSF DMR-1751308. K.T. and E.S. gratefully acknowledge support from the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linköping University (faculty grant SFO-Mat-LiU no. 2009-00971). K.T. was also supported by the Swedish Foundation for Strategic Research and E.S. is supported by Vetenskapsrådet VR-2017-04910.

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Paulsen, B.D., Tybrandt, K., Stavrinidou, E. et al. Organic mixed ionic–electronic conductors. Nat. Mater. 19, 13–26 (2020).

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