Proton-penetrable Nafion-induced phase separation in organic semiconductors for high-performance organic electrochemical transistors

Organic electrochemical transistors (OECTs) are promising for highly sensitive chemical and biological detections, because of their signal amplification, low operating voltage, solution compatibility, and high biocompatibility. However, OECTs, particularly the semiconductor layer, still need to be optimized for improving their output performances. Herein, by introducing Nafion, a proton penetrable polymer, into typical semiconductor layers of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and poly(3-hexylthiophene) (P3HT), we realize a significant enhancement (up to 10-fold and 4-fold respectively) in transconductance of OECTs. The enhancements are attributed to the introduction of Nafion domains in the semiconductor channel, which increases the surface area of the semiconductor channel and promotes the ion doping/de-doping of the channel. In addition, the Nafion-including OECTs exhibit a fast response time of 20 milliseconds. Due to the improved transconductance and response time, the obtained OECT demonstrates sensitive detections of the pH value and glucose. This work provides a simple and effective method for improving the performance of OECTs, which will be promising in the sensitive and reliable detection of metabolites.