Sources and Mechanism of Degradation in p-Type Thiophene-Based Organic Electrochemical Transistors
AuthorsSchafer, Emily A.
Paulsen, Bryan D.
KAUST DepartmentKing Abdullah University of Science and Technology (KAUST), KAUST Solar Center, Thuwal 23955-6900, Saudi Arabia
Chemical Science Program
KAUST Solar Center (KSC)
Embargo End Date2023-04-12
Permanent link to this recordhttp://hdl.handle.net/10754/676265
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AbstractAchieving high stability is critical for the implementation of organic electrochemical transistors (OECTs) in more diverse and demanding applications. However, the sources and mechanisms of OECT degradation have not been rigorously explored. Here, we employ a variety of biasing schemes to separate the relative effects of oxidative bias stress, reductive bias stress, and current stress on degradation of thiophene-based, p-type OECTs. We find that accelerated degradation arises from the compounding effects of simultaneous oxidative and reductive bias stress and is common across several thiophene-based channel materials. To understand the underlying mechanism of OECT channel degradation, we explore the individual contributions of dissolved oxygen and source-drain electrode materials. We determine that the reaction of dissolved oxygen at the buried Au/OMIEC interface of the drain electrode experiencing reductive potentials produces a mobile reactive species that aggressively degrades the oxidized OMIEC throughout the device, destroying its conjugation and disrupting electronic charge transport. Importantly, we find that this mechanism can be disrupted by alternatively removing oxygen, avoiding reductive potentials in the device biasing scheme, replacing Au electrodes with a noncatalytic alternative, or passivating Au electrodes with self-assembled monolayers. These conclusions can inform both future standards of stability testing in the field as well as design considerations of OECT implementation in long-term applications.
CitationSchafer, E. A., Wu, R., Meli, D., Tropp, J., Moser, M., McCulloch, I., Paulsen, B. D., & Rivnay, J. (2022). Sources and Mechanism of Degradation in p-Type Thiophene-Based Organic Electrochemical Transistors. ACS Applied Electronic Materials. https://doi.org/10.1021/acsaelm.1c01171
SponsorsE.A.S. and J.R. gratefully acknowledge funding support from Sloan under award no. FG-2019-12046. R.W., B.D.P., and J.R. acknowledge support from the National Science Foundation grant no. NSF DMR-1751308. E.A.S, R.W., D.M., M.M., I.M., and J.R. acknowledge funding from King Abdullah University of Science and Technology Office of Sponsored Research (OSR) under award no. OSR-2019-CRG8-4086 and OSR-2018-CRG7-3749.
J.T. was primarily supported by an Office of Naval Research (ONR) Young Investigator Program (YIP) award no. N00014-20-1-2777. M.M. and I.M. acknowledge funding from ERC Synergy Grant SC2 (610115), the European Union’s Horizon 2020 research and innovation program under grant agreement n°952911, project BOOSTER, and grant agreement n°862474, project RoLA-FLEX, as well as EPSRC Project EP/T026219/1.
This work utilized the Keck-II facility of Northwestern University’s NUANCE Center and Northwestern University Micro/Nano Fabrication Facility (NUFAB), which are both partially supported by the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the Materials Research Science and Engineering Center (NSF DMR-1720139), the State of Illinois, and Northwestern University.
The Keck-II facility is partially supported by the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.
This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Special thanks to J. Strzalka for beamline support.
PublisherAmerican Chemical Society (ACS)
JournalACS Applied Electronic Materials