Electrolyte PH Drives A Crossover To Proton-Coupled Doping In N-Type Organic Mixed Conductors

Author

• Seth R. Jackson
• Miharu Koh
• James F. Ponder
• Arnel Besic
• Shelley D. Minteer, Missouri University of Science and TechnologyFollow
• Connor G. Bischak

Abstract

Organic mixed ionic-electronic conductors (OMIECs) have emerged as promising materials for applications ranging from bioelectronics to neuromorphic computing to charge storage. Many of these applications require n-type OMIECs, whose operation is strongly influenced by the electrolyte. Although factors such as counterion identity and concentration are known to impact electrochemical doping, the role of electrolyte pH, which sets the proton activity of the electrolyte, remains comparatively underexplored, especially for n-type OMIECs. Here, we investigate how proton activity governs electrochemical doping in the n-type polymer p(gNDI-T2) across a pH range of 1–10 and uncover a sharp mechanistic crossover at pH ∼4. Below this threshold, doping proceeds through super-Nernstian proton-coupled electron transfer (PCET), while above it, conventional K⁺-compensated doping prevails. Using a suite of operando methods, we find that doping at low pH results in minimal mass transfer to the polymer and the emergence of localized polaronic states. These mechanistic differences can directly impact device operation, as in organic electrochemical transistors (OECTs), proton-compensated species significantly decrease electronic charge-carrier mobility. More broadly, these results establish electrolyte pH as a key design parameter for n-type OMIECs, one that must be controlled for reliable device operation, and that may also be harnessed for applications requiring pH-responsive behavior.

Recommended Citation

S. R. Jackson et al., "Electrolyte PH Drives A Crossover To Proton-Coupled Doping In N-Type Organic Mixed Conductors," Advanced Functional Materials, vol. 36, no. 70, article no. e77433, Wiley; Wiley-VCH Verlag, Aug 2026.

The definitive version is available at https://doi.org/10.1002/adfm.77433

Department(s)

Chemistry

Comments

Camille and Henry Dreyfus Foundation, Grant CHE‐2304613

Keywords and Phrases

crossover; doping; electrical conductor; electrolyte

International Standard Serial Number (ISSN)

1616-3028; 1616-301X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Wiley; Wiley-VCH Verlag, All rights reserved.

Publication Date

31 Aug 2026