MSE Graduate Seminar: Toward Printed Electrolyte-Gated Transistors for Flexible Electronics

Electrolyte-gated field effect transistors (EGFETs) have gathered much attention in the last few decades due to their key role in enabling potential printed, low-cost, low-power, portable, and flexible electronics in applications such as wearable sensors, flexible solar cells, and e-textiles. To further the portability and commercial viability of EGFET-based printed electronics, this study explores the applications of polymer electrolytes in EGFET and their compatibility with inexpensive silver electrodes to replace expensive and process-intensive gold electrode contacts. Several additive manufacturing techniques such as inkjet and screen printing were used to fabricate electrodes in silver and gold for proof-of-concept testing. The electrochemical stability and capacitance characteristics were evaluated for a series of proton and neutral pH ion-conducting electrolytes. Among these aqueous based polymer electrolytes is lithium nitrate (LiNO3) salt in polyvinyl alcohol (PVA) matrix. LiNO3/PVA is promising due to its wider electrochemical window on account of being a neutral pH ion-conducting electrolyte, as well as its high ionic conductivity and specific capacitance which are necessary for efficient electric double layer gating in sub-1V EGFETs. Subsequently, this study explores the transistor performance, optimization, and outlook of this electrolyte for silver electrode EGFETs.