PEDOT:PSS deposition in OECTs: Inkjet printing, aerosol jet printing and spin coating

Abstract

As the world moves towards integrating new functionalities into everyday objects, the demand for diverse substrates grows, making additive manufacturing an invaluable tool. Organic electronic materials have played a major role in this transition thanks to their excellent electronic and mechanical properties, adaptability and solution processability.

The aim of this study is to compare spin coating, inkjet printing (IJP), and aerosol jet printing (AJP) for applying poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the channel material in organic electrochemical transistors (OECTs). This work investigates the often-overlooked impact of deposition techniques on the electrical performance of OECTs. Spin coating has been analysed as a reference technique, while AJP and IJP are addressed as promising pathways towards fully printed OECTs.

The normalized transconductance and I_on/I_off ratio have been analysed as figures of merit for this study. AJP devices have shown the best performance, displaying a normalized transconductance of 885 S∙nm and an I_on/I_off ratio around 10³. The spin coated OECTs showed a slightly lower normalized transconductance (740 S∙nm) and much lower I_on/I_off ratio in the order of 10¹. Last, IJP exhibited a transconductance of 433 S∙nm and a I_on/I_off ratio in the order of 10².

This work could be beneficial for a wide range of applications, adding an additional degree of freedom to the tunability of the OECT channel properties. It also opens the discussion for more comprehensive studies on the films from a materials perspective.