Salts as Additives: A Route to Improve Performance and Stability of n-Type Organic Electrochemical Transistors

David Ohayon, Lucas Q. Flagg, Andrea Giugni, Shofarul Wustoni, Ruipeng Li, Tania C. Hidalgo Castillo, Abdul Hamid Emwas, Rajendar Sheelamanthula, Iain McCulloch, Lee J. Richter, Sahika Inal*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Organic electrochemical transistors (OECTs) are becoming increasingly ubiquitous in various applications at the interface with biological systems. However, their widespread use is hampered by the scarcity of electron-conducting (n-type) backbones and the poor performance and stability of the existing n-OECTs. Here, we introduce organic salts as a solution additive to improve the transduction capability, shelf life, and operational stability of n-OECTs. We demonstrate that the salt-cast devices present a 10-fold increase in transconductance and achieve at least one year-long stability, while the pristine devices degrade within four months of storage. The salt-added films show improved backbone planarity and greater charge delocalization, leading to higher electronic charge carrier mobility. These films show a distinctly porous morphology where the interconnectivity is affected by the salt type, responsible for OECT speed. The salt-based films display limited changes in morphology and show lower water uptake upon electrochemical doping, a possible reason for the improved device cycling stability. Our work provides a new and easy route to improve n-type OECT performance and stability, which can be adapted for other electrochemical devices with n-type films operating at the aqueous electrolyte interface.

Original languageEnglish (US)
Pages (from-to)242-254
Number of pages13
JournalACS Materials Au
Volume3
Issue number3
DOIs
StatePublished - May 10 2023

Bibliographical note

Funding Information:
L.Q.F. acknowledges the support of a NIST-National Research Council fellowship. This research used beamline 11BM (CMS) of the National Synchrotron Light Source and U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract No. DE-SC0012704. S.I. This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) under Award Nos. OSR-2019-CRG8-4095, URF/1/4073-01, and ORA-2021-CRG10-4650.

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.

Keywords

  • additive
  • aqueous electrolytes
  • bioelectronics
  • doping
  • electron transporting polymers
  • organic electrochemical transistors
  • salt

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry

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