Serial Resistance Effect on Organic Electrochemical Transistors’ Transconductance

Organic electrochemical transistors (OECTs) with variable electrode resistance and channel conductivity were studied. The effect of parasitic serial resistance on OECT function, especially transconductance, was evaluated. It was shown that due to the nonoptimized serial resistance, the transistors can have a transconductance lower by tens of percentage compared to the theoretical intrinsic transconductance. We show here that by simply reducing the contacts’ resistance, it is possible to prepare a planar OECT with a high transconductance of 108 mS, which is close to the intrinsic transconductance of 121 mS. These values represent some of the highest ones reported so far, despite the fact that the poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) used here has a lower conductivity.