High Performance Chemical Sensor with Field-Effect Transistors Array for Selective Detection of Multiple Ions

Abstract Monitoring of phosphate, nitrate, and potassium ions in nutrient solution or water, which play critical roles in all living organisms, is important in regulating and/or supplying right amount of such essential nutrients for plant growth in a smart farm. Herein, we report a novel approach for simultaneous, selective detection of multi-ions with ZnO nanorods field-effect transistors (FETs) array sensor. The fabricated sensor platform provided fast responses to wide linear ranges of PO4-3, NO3−, and K+ ions with high sensitivity and selectivity and low detection limits. More importantly, the chemical sensor platform is successfully used for detection of multiple ions in a real nutrient solution, showing an excellent agreement of 98-100 % and remarkable stability and reproducibility of sensing performance, indicating a great potential to become a useful tool not only for hydroponic cultivation in a smart farm but also for a water maintaining system.