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Understanding asymmetric switching times in accumulation mode organic electrochemical transistors


Understanding the factors underpinning device switching times is crucial for the implementation of organic electrochemical transistors in neuromorphic computing, bioelectronics and real-time sensing applications. Existing models of device operation cannot explain the experimental observations that turn-off times are generally much faster than turn-on times in accumulation mode organic electrochemical transistors. Here, using operando optical microscopy, we image the local doping level of the transistor channel and show that turn-on occurs in two stages—propagation of a doping front, followed by uniform doping—while turn-off occurs in one stage. We attribute the faster turn-off to a combination of engineering as well as physical and chemical factors including channel geometry, differences in doping and dedoping kinetics and the phenomena of carrier-density-dependent mobility. We show that ion transport limits the operation speed in our devices. Our study provides insights into the kinetics of organic electrochemical transistors and guidelines for engineering faster organic electrochemical transistors.

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Fig. 1: OECT response times.
Fig. 2: Comparison between OECT and UV–visible spectroelectrochemistry.
Fig. 3: Operando optical microscope coupled with OECT switching.
Fig. 4: OECT mobility and carrier density.
Fig. 5: Dependency of OECT response times on the operation variables.

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Data availability

The data that support the findings of this study are available within the paper and its Supplementary Information. Source data are provided with this paper. Additional data may be requested from the authors.


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This paper is based on research supported primarily by the National Science Foundation, first under DMR-2003456 and then under DMR-2309577. K.Y., Z.S. and C.-Z.L. acknowledge support from the National Natural Science Foundation of China (22125901) for supporting the synthesis of the PB2T-TEG polymer. J.W.O. and C.K.L.’s contributions to P3MEEMT polymer synthesis are based in part on work supported by the National Science Foundation, DMREF-1922259. Part of this work (transistor fabrication) was conducted at the Washington Nanofabrication Facility/Molecular Analysis Facility, a National Nanotechnology Coordinated Infrastructure (NNCI) site at the University of Washington with partial support from the National Science Foundation via awards NNCI-1542101 and NNCI-2025489.

Author information

Authors and Affiliations



J.G. and S.E.C. contributed equally to the work. J.G., S.E.C. and D.S.G. conceived the project, designed the experiments and discussed the results together. J.G. and S.E.C. performed the experiments and analysed the data. S.E.C. wrote the first draft and J.G. made the figures. R.G. performed the SPICE circuit modelling. C.G.B designed the preliminary microscope experiment. K.Y., Z.S. and C.-Z.L. provided the PB2T-TEG polymer. J.W.O. and C.K.L. provided the P3MEEMT polymer. J.G., S.E.C., R.G. and D.S.G. revised the paper with input from all the authors.

Corresponding author

Correspondence to David S. Ginger.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–20, Notes 1–8 and Tables 1–5.

Supplementary Video 1

Doping video coupled with the OECT drain current.

Supplementary Video 2

Comparison of doping front propagation at various VD values.

Supplementary Video 3

Five-cycle switching of PB2T-TEG.

Supplementary Video 4

P3MEEMT switching.

Supplementary Video 5

The VD and VG applied at the same time during transistor turn-on.

Supplementary Video 6

Dedoping video coupled with the OECT drain current.

Source data

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Source data for Fig. 1a.

Source Data Fig. 2

Source data for Fig. 2c–h.

Source Data Fig. 3

Source data for Fig. 3b,d–h,j,k.

Source Data Fig. 4

Source data for Fig. 4a,b.

Source Data Fig. 5

Source data for Fig. 5a–e.

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Guo, J., Chen, S.E., Giridharagopal, R. et al. Understanding asymmetric switching times in accumulation mode organic electrochemical transistors. Nat. Mater. 23, 656–663 (2024).

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