Development of high-performance miniaturized UV-activated sensors for real-time nitrate detection in water and soil

Nutrient measurement devices can provide valuable information by monitoring soil and water parameters in real time, helping farmers optimize fertilizer usage and improve agricultural practices. In this work, engineered nanomaterials coupled with ultraviolet light-emitting diodes (UV-LEDs) create an advanced sensor for nitrate detection for the first time. The sensor contains a photocatalyst designed for nitrate photoreduction and a UV-LED for the emission of UV radiation to activate the sensing node. The spin coating technique was employed in sensor fabrication, ensuring simplicity and scalability. Using boron nitride nanosheets as a novel photoreactive sensing layer on gold interdigitated microelectrodes, this study establishes a clear relationship between nitrate concentration and the sensor signal under UV irradiation. The sensor was capable of measuring nitrate concentration over a wide range of 1 to 70 ppm Nitrate-N with a rapid response time under a UV-LED. These photo-induced chemiresistive devices show great promise in transforming agriculture by delivering real-time data on nutrient levels in fields, mitigating the environmental impacts of nitrate leaching and fostering more sustainable farming practices.