Laser-Induced Graphene Electrodes for Organic Electrochemical Transistors (OECTs)

Organic electrochemical transistors (OECTs) have drawn significant interest because of their low cost, biocompatibility, and ease of fabrication, allowing them to be utilized in various applications including flexible displays, electrochemical sensing, and biosensing. Key components of OECTs are the gate, source, and drain electrodes. Herein, OECTs with laser-induced graphene (LIG) electrodes are demonstrated. The electrode patterns for the source, drain, and gate are created by converting the polymer substrate polyimide (PI) into LIG using a scanned laser. The process is simple and inexpensive without complicated chemical synthesis routines or expensive materials such as gold. Patterns can be customized quickly and digitally. The low-cost and porous LIG electrodes with low contact resistance and good electrical stability play an essential role in device performance. The minimum sheet resistance achieved with this laser method for the square patterned electrodes is 7.86 & omega; sq(-1). The LIG-based OECTs demonstrate good electrical modulation with ON-OFF ratio of 72.80 and high ON current on the order of mA. The LIG-based OECTs exhibit comparable or better performance in comparison with other reports of OECTs on plastic substrates using more complex fabrication methods in terms of OFF current, ON current, transconductance (gm), and contact resistance.