"Additive Processing of Conjugated Polyelectrolyte-Based Organic Electrochemical Transistors"

H. Wakidi^a,b, T. Nguyen-Dang^a,c, K. Li^a,d, J. Chatsirisupachai^a,e, E. Tanaka^e, H. M. Luong^a, V. Promarak^e, R. Segalman^d,f, T.-Q. Nguyen^a,b

^aCenter for Polymers and Organic Solids, University of California Santa Barbara, Santa Barbara, CA 93106, USA.

^bDepartment of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.

^cCollege of Engineering and Computer Science, VinUniversity, Hanoi, Vietnam.

^dChemical Engineering Department, University of California, Santa Barbara, CA 93106, USA.

^eDepartment of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand.

^fMaterials Department, University of California, Santa Barbara, CA 93106, USA.

Organic electrochemical transistors (OECTs) have emerged as a promising platform for the development of bioelectronic devices and systems, thanks to their biocompatibility, ease of fabrication, low power consumption, and low operating voltage.  OECTs rely on the use of mixed ion-electron conductors (MIECs) as the active material, and therefore, their performance is strongly determined by the electrical and ionic transport properties of these materials. In this work, we demonstrate the use of the anionic polyelectrolyte poly[styrenesulfonate] (PSS) as performance enhancing additive for dual operation-mode OECTs based on a self-doped conjugated polyelectrolyte (CPE-K). Systematic characterization of film properties and device performance on pristine and blend films were conducted.  We show that PSS at low concentrations increases the charge carrier mobility by one order of magnitude within the active material, without significantly altering the film morphology and electrochemical properties. These blend systems result in devices with a five-fold increase in transconductance response compared to devices based on pristine CPEs and provide a route towards the development of high-performance CPE-based OECTs. This work was supported by the National Science Foundation through the Materials Research Science and Engineering Center (MRSEC) at UC Santa Barbara: NSF DMR-2308708 (IRG-1).