Organic Electrochemical Transistors and Diodes Based on Chemically Dedoped PEDOT:PSS

Abstract

Poly（3,4-ethylenedioxythiophene）:poly（styrenesulfonate） （PEDOT:PSS）, one of the most representative organic mixed ionic–electronic conductors （OMIECs）, has attracted considerable attention in the field of bioelectronics. However, PEDOT:PSS possesses intrinsic limitations, including poor stability in aqueous environments and depletion- mode operation characteristics, which hinder the achievement of high rectification ratios required for efficient diode performance. In this study, we propose a device architecture that enables the stable utilization of PEDOT:PSS as a channel material. The electrical properties of the polymer were modulated through chemical dedoping using amine-based materials, while sulfuric acid treatment was introduced to simultaneously improve electrical performance and structural stability in aqueous environments. The modified PEDOT:PSS films were integrated into asymmetrically designed electrode structures with an EMIM:OTf ionic liquid electrolyte to fabricate organic electrochemical diodes （OECDs）. The rectification characteristics were systematically investigated under various treatment conditions, and a rectification ratio greater than 100, suitable for OECD operation, was achieved in the pristine PEDOT:PSS condition without sulfuric acid treatment. In addition, the dedoped PEDOT:PSS films were analyzed using X-ray photoelectron spectroscopy （XPS） and Raman spectroscopy to investigate the chemical structural changes within the films. These analyses support the observed OECD behavior of PEDOT:PSS devices. The developed dedoped PEDOT:PSS-based OECDs are expected to efficiently function as current rectification and switching components in next- generation bioelectronic circuits.