Direct quantification of ion composition and mobility in organic mixed ionic-electronic conductors

Journal article

Ruiheng Wu, Xudong Ji, Qing Ma, Bryan D Paulsen, Joshua Tropp, Jonathan Rivnay
Sci. Adv., vol. 10(17), 2024 Apr 26, pp. eadn8628

DOI: 10.1126/sciadv.adn8628

Cite

APA Click to copy
Wu, R., Ji, X., Ma, Q., Paulsen, B. D., Tropp, J., & Rivnay, J. (2024). Direct quantification of ion composition and mobility in organic mixed ionic-electronic conductors. Sci. Adv., 10(17), eadn8628. https://doi.org/10.1126/sciadv.adn8628

Chicago/Turabian Click to copy
Wu, Ruiheng, Xudong Ji, Qing Ma, Bryan D Paulsen, Joshua Tropp, and Jonathan Rivnay. “Direct Quantification of Ion Composition and Mobility in Organic Mixed Ionic-Electronic Conductors.” Sci. Adv. 10, no. 17 (April 26, 2024): eadn8628.

MLA Click to copy
Wu, Ruiheng, et al. “Direct Quantification of Ion Composition and Mobility in Organic Mixed Ionic-Electronic Conductors.” Sci. Adv., vol. 10, no. 17, Apr. 2024, p. eadn8628, doi:10.1126/sciadv.adn8628.

BibTeX Click to copy

@article{ruiheng2024a,
  title = {Direct quantification of ion composition and mobility in organic mixed ionic-electronic conductors},
  year = {2024},
  month = apr,
  day = {26},
  issue = {17},
  journal = {Sci. Adv.},
  pages = {eadn8628},
  volume = {10},
  doi = {10.1126/sciadv.adn8628},
  author = {Wu, Ruiheng and Ji, Xudong and Ma, Qing and Paulsen, Bryan D and Tropp, Joshua and Rivnay, Jonathan},
  month_numeric = {4}
}

Ion transport in organic mixed ionic-electronic conductors (OMIECs) is crucial due to its direct impact on device response time and operating mechanisms but is often assessed indirectly or necessitates extra assumptions. Operando x-ray fluorescence (XRF) is a powerful, direct probe for elemental characterization of bulk OMIECs and was used to directly quantify ion composition and mobility in a model OMIEC, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS), during device operation. The first cycle revealed slow electrowetting and cation-proton exchange. Subsequent cycles showed rapid response with minor cation fluctuation (~5%). Comparison with optical-tracked electrochromic fronts revealed mesoscale structure–dependent proton transport. The calculated effective ion mobility demonstrated thickness-dependent behavior, emphasizing an interfacial ion transport pathway with a higher mobile ion density. The decoupling of interfacial effects on bulk ion mobility and the decoupling of cation and proton migration elucidate ion transport in conventional and emerging OMIEC-based devices and has broader implications for other ionic conductors writ large.