Subthreshold Operation of Organic Electrochemical Transistors for Biosignal Amplification

Vishak Venkatraman, Jacob T. Friedlein, Alexander Giovannitti, Iuliana P. Maria, Iain McCulloch, Robert R. McLeod, Jonathan Rivnay*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


With a host of new materials being investigated as active layers in organic electrochemical transistors (OECTs), several advantageous characteristics can be utilized to improve transduction and circuit level performance for biosensing applications. Here, the subthreshold region of operation of one recently reported high performing OECT material, poly(2-(3,3′-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-[2,2′-bithiophen]-5-yl)thieno[3,2-b]thiophene), p(g2T-TT) is investigated. The material's high subthreshold slope (SS) is exploited for high voltage gain and low power consumption. An ≈5× improvement in voltage gain (AV) for devices engineered for equal output current and 370× lower power consumption in the subthreshold region, in comparison to operation in the higher transconductance (g m), superthreshold region usually reported in the literature, are reported. Electrophysiological sensing is demonstrated using the subthreshold regime of p(g2T-TT) devices and it is suggested that operation in this regime enables low power, enhanced sensing for a broad range of bioelectronic applications. Finally, the accessibility of the subthreshold regime of p(g2T-TT) is evaluated in comparison with the prototypical poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and the role of material design in achieving favorable properties for subthreshold operation is discussed.

Original languageEnglish (US)
Article number1800453
JournalAdvanced Science
Issue number8
StatePublished - Aug 2018

Bibliographical note

Funding Information:
The authors acknowledge the staff support of the Northwestern’s microfabrication facility (NUFAB). This work utilized the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which is partially supported by the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (Grant No. NSF ECCS-1542205), the Materials Research Science and Engineering Center (Grant No. DMR-1720139), the State of Illinois, and Northwestern University. The authors also wish to acknowledge Mary J. Donahue for her assistance with the fabrication of the PEDOT:PSS-based OECT reported here. J.T.F. and R.R.M. acknowledge funding from the National Science Foundation (Grant No. ECCS 1509909).

Publisher Copyright:
© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • electroencephalography (EEG)
  • organic electrochemical transistors
  • subthreshold
  • voltage amplifiers

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)


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