Self-aligned, laser-cut organic electrochemical transistors

Organic electrochemical transistors (OECTs) are switches and sensor devices that take advantage of bulk transport of ionic/electronic species in the active channel material, resulting in high amplification and robust electrical characteristics. Traditional techniques used to pattern OECT channels often call for multiple photolithography steps, unwanted parasitic capacitance and waste of active material. In this work we introduce a new method for OECT patterning which makes use of a hydrophobic insulation layer combined with a laser cutting method that provides self-alignment of source/drain contacts, insulation and channel, and allows for the active material to be 'dragged and dropped' into laser cut OECT channels. We show that this method preserves the high performance of OECTs with good reproducibility across an array. In addition, we show that this method is compatible with flexible arrays which are sought in a number of biological applications. We show that different types of OECTs can be created on the flexible array, including free-standing and through-hole OECT channels, which may be advantageous in different biosensing settings ranging from neural signal acquisition to regenerative applications. This approach takes advantage of the bulk transport inherent in OECTs to introduce a new fabrication method that opens new avenues for patterning bioelectronic sensors that may be otherwise limited with traditional patterning approaches.