De-doping Agent to Achieve Enhancement-Mode PEDOT:PSS Organic Electrochemical Transistors

Poly(2,3-dihydrothieno-1,4-dioxin)（PEDOT) stands out among many conductive polymers due to its simple molecular structure, high conductivity, good stability and small energy gap, and has received extensive research and attention. It is a common material for organic electrochemical transistors. Organic electrochemical transistors (OECTs) have low operating voltage, simple structure, can be operated in an aqueous environment, good biocompatibility and excellent signal amplification characteristics, especially in sensors and other fields The field of biosensing has broad application prospects. Most of the current organic electrochemical transistor devices are made of Poly(3,4-ethylenedioxythiophene) /poly(styrenesulfonate)(PEDOT: PSS).

PEDOT/PSS film has high transparency, good flexibility and excellent thermal stability. It is very good in the application of organic electrochemical transistors. However, 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.

In order to solve this problem, researchers from the Eindhoven University of Technology in the Netherlands and Stanford University in the United States have collaborated to use aliphatic amine dedopant molecules to cast an enhanced PEDOT:PSS organic electrochemical transistor from a single aqueous solution.

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.

Related links: PEDOT: PSS

references:

Keene et al., Enhancement-Mode PEDOT:PSS Organic Electrochemical Transistors Using Molecular De-Doping. Adv. Mater. 2020, DOI: 10.1002/adma.202000270