Enhancement-Mode PEDOT:PSS Organic Electrochemical Transistors Using Molecular De-Doping

Scott T Keene; Tom P A van der Pol; Dante Zakhidov; Christ H L Weijtens; René A J Janssen; Alberto Salleo; Yoeri van de Burgt

doi:10.1002/adma.202000270

Enhancement-Mode PEDOT:PSS Organic Electrochemical Transistors Using Molecular De-Doping

Adv Mater. 2020 May;32(19):e2000270. doi: 10.1002/adma.202000270. Epub 2020 Mar 23.

Authors

Scott T Keene¹, Tom P A van der Pol², Dante Zakhidov¹, Christ H L Weijtens², René A J Janssen², Alberto Salleo¹, Yoeri van de Burgt³

Affiliations

¹ Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA.
² Molecular Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5612AJ, Netherlands.
³ Microsystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5612AJ, Netherlands.

PMID: 32202010
DOI: 10.1002/adma.202000270

Abstract

Organic electrochemical transistors (OECTs) show great promise for flexible, low-cost, and low-voltage sensors for aqueous solutions. The majority of OECT devices are made using the polymer blend poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), in which PEDOT is intrinsically doped due to inclusion of PSS. Because of this intrinsic doping, PEDOT:PSS OECTs generally operate in depletion mode, which results in a higher power consumption and limits stability. Here, a straightforward method to de-dope PEDOT:PSS using commercially available amine-based molecular de-dopants to achieve stable enhancement-mode OECTs is presented. The enhancement-mode OECTs show mobilities near that of pristine PEDOT:PSS (≈2 cm² V^-1 s^-1 ) with stable operation over 1000 on/off cycles. The electron and proton exchange among PEDOT, PSS, and the molecular de-dopants are characterized to reveal the underlying chemical mechanism of the threshold voltage shift to negative voltages. Finally, the effect of the de-doping on the microstructure of the spin-cast PEDOT:PSS films is investigated.

Keywords: aliphatic amines; bioelectronics; enhancement-mode transistor; molecular doping; organic electrochemical transistor; poly(ethylenedioxythiophene):poly(styrene sulfonate.

Abstract

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