Integrated Low Voltage Ion Sensing Organic Field Effect Transistor System on Plastic

An ion-sensitive organic field-effect transistor (ISOFET) system was fabricated by integrating a low voltage OFET, a thin-film flexible solid state reference electrode, and a working electrode on plastic substrate. The low voltage OFET was realized by reducing the sub-gap density of states at the channel without relying on large gate dielectric capacitance, and fabricated with all additive printing/coating processes. The fabricated plastic ISOFET sensor is able to be operated in a 3.3 V battery powered handheld electronic system for real time reliable pH monitoring. A simple calibration method was developed with the system for accurately converting the sensed current to pH values.