(Invited) Designing Materials for Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) have gained a renewed interest in the field or bioelectronics and biosensors. OECTs act as amplifiers and therefore provide high signal/noise ratio for detecting a wide range of biomolecules or physiological signals. A critical component of the OECTs is the channel material, which is an organic mixed ionic-electronic conductor (OMIEC). In simpler terms, OMIECs are (semi)conducting polymers that can transport electronic charges (electrons or holes), transport ionic charges, and display a capacitive behavior (reversible doping/dedoping process). Amongst OMIECs, the polyelectrolyte complex PEDOT:PSS has been the most widely used, likely due to its commercial availability and ease of use as a water dispersion. PEDOT:PSS, however, is a black box with a proprietary composition and does not have particularly reactive handles for functionalization. As such, it is difficult to modify its properties for specific applications in biosensing. In this talk, I will describe my team’s work in understanding PEDOT:PSS and methods for modifying it using covalent organic chemistry. Our principal approach is to control the synthesis of the PSS polymer and/or modify it with functional units by using random or block copolymerization. This approach was successfully used to achieve high performance OECT devices and new conductive materials with temperature or light-response.