Inkjet Printable Semiconducting Inks for Enhancement‐Mode Organic Electrochemical Transistors

Abstract Additive manufacturing technologies offer a promising avenue for advancing the microfabrication of organic electronic devices. In this study, inkjet printable semiconducting inks derived from commercially available p‐type and n‐type conjugated polymers, namely poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and poly(benzimidazobenzophenanthroline) (BBL) are developed. These inks are used to fabricate organic electrochemical transistor (OECT) channels at a deposition resolution of 20 µm with high electrochemical stability under prolonged biasing stress. The versatility of the inks is demonstrated through the fabrication of OECTs on various substrates, including glass, polyimide, and paper, and in one example, all device components are printed exclusively from PEDOT:PSS. The de‐doped PEDOT:PSS channel is integrated with a BBL channel, constructing printed monolithic electrochemical complementary amplifiers performing as a NOT logic gate. Furthermore, The applicability of the PEDOT: PSS‐based enhancement mode device operation in electrochemical sensing, achieving high sensitivity to physiologically relevant concentrations of ascorbic acid is showcased. This work aligns with the objective of democratizing access to advanced electronic materials and devices, facilitating fabrication processes without the need for scarce materials, expensive equipment, or specialized facilities.