Fully-Printed Sensor Based Extended Gate Field Effect Transistors for Wireless Monitoring of Potassium and Ammonium Ions.

This paper presents an extended gate field effect transistor based ion sensing platform utilizing flexible printed ion selective electrodes. A custom-printed circuit board with a Bluetooth-enabled microcontroller module enables wireless monitoring of the transistor's transfer characteristics modulated by the ion concentration in the target solution. The utilization of printing techniques such as inkjet printing and direct 3D writing provide the scope for facile and cost-effective fabrication. The system has been utilized for remote monitoring of Potassium and Ammonium ions with ideal Nernstian response, high sensitivity, and selectivity. This work provides a promising path for real-time and continuous ion monitoring which has crucial implications for health, industry, and environmental applications.