Simple Approach for Building High Transconductance Paper-Based Organic Electrochemical Transistor (OECT) for Chemical Sensing

Organic electrochemical transistors (OECTs) have attracted great interest in the last few years as biochemical sensors due to their outstanding analytical performance, versatility, stability, and easiness of fabrication. While thin-film OECTs have been studied extensively, their manufacturing still presents some challenges. This report presents a simple approach for developing OECT using a paper substrate and a thick-film approach that shows outstanding performance. The channel is hand-made by dip pen deposition of the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS). This allows reproducible channel thickness in the order of 6 μm, well above the conventionally used values. This device displays a high transconductance that exceeds 40 mS and an on-to-off current ratio of 3.8 × 103 comparable or superior to the state-of-the-art paper-based OECTs. The advantages of this approach are illustrated with the detection of H2O2 and glucose, obtaining sensitivities above 1.5 mA/dec. This simplified approach and high sensitivity may help to extend the use of the OECT-based sensors, particularly in the distributed and point-of need applications.