The Electrochemical Transistor: a device based on the Electrochemical control of a polymer Polaronic state. The PCPDT-BT as a case study

TL;DR

This paper introduces an electrochemical transistor concept where an organic semiconductor's conductivity is controlled via electrochemical polarization, integrating solid-state and electrochemical cell principles, demonstrated with PCPDT-BT.

Contribution

It presents a novel device architecture combining electrochemistry with organic electronics, using in-situ IR spectroscopy to study polaronic state modulation.

Findings

Conductivity modulation of PCPDT-BT via electrochemical potential.

In-situ IR spectra confirm polaronic state formation.

Device demonstrates electrochemical control of organic semiconductor.

Abstract

This work presents an original concept directed to implement an unconventional methodology where a device is produced by integrating a solid-state circuitry concept and an electrochemistry cell. In our experimental system an organic semiconductor, (PCPDT-BT), serves both as the gate and working electrode. Gating is obtained via electrochemical polarization exploiting a conventional three electrodes electrochemical cell placed on top of a traditional source/drain/gate solid-state device configuration. Source/drain conduction is probed via impedance measurement (electrochemical impedance spectroscopy, EIS) performed as a function of time at constant frequency, under constant potential control. The conductivity of the PCPDT-BT is due to the polaronic state induced via application of a suitable electrochemical potential (in the oxidation regime), as it is proved by infrared (IR) spectra recorded in-situ/in-operando (in attenuated under total reflection, ATR, mode) upon both electrochemical and chemical ionization/doping of the PCPDT-BT.