An electrochemical approach to the realization of OECTs: a polypyrrole case study

Organic electrochemical transistors (OECTs) are organic-based devices with interesting electronic properties such as an electron/ion transduction capability, which is essential in various applications. The scientific community is showing great interest in this type of device, exploiting their properties and studying the effect of varying preparation protocols on their performance. OECTs are typically designed starting from commercial PEDOT:PSS dispersions, and their fabrication involves multi-step photolithographic methods. However, several groups are developing alternative methodologies and protocols and different conductive polymers for device realization. Here, we report a facile, reliable, and mask-less electrochemical approach to the realization of polypyrrole (PPy)-based OECTs. Our strategy ensures the realization of conductive channels made of PPy with controlled properties while maintaining low-cost and low-waste fabrication. The results are supported by electronic characterization combined with a deep electrochemical analysis, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, the molecular structural features of the produced materials are evaluated by means of Raman spectroscopy analyses. All of these characterizations allow for the optimization of the synthesis protocols for channel formation and ensure the fabrication of a well-performing OECT with a low voltage range (< 1V), good transconductance (g_m = 0.26 mS), and excellent stability for pulse stimulation. These outcomes convincingly demonstrate that the proposed electrochemical approach is a simple yet effective way to exploit PPy in OECT applications [1].

[1] Carcione R. et al. “One-Pot and Mask-Less Realization Approach for Polypyrrole−Polydopamine-Based Organic Electrochemical Transistors”, ACS Applied Electronic Materials https://doi.org/10.1021/acsaelm.5c00124