Sub-ppm NO2 Detection through Chipless RFID Sensor Functionalized with Reduced SnO2

• Published in: Chemosensors Vol. 11; no. 7; p. 408
• Main Authors: Mulloni, Viviana, Gaiardo, Andrea, Marchi, Giada, Valt, Matteo, Vanzetti, Lia, Donelli, Massimo, Lorenzelli, Leandro
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-07-2023
• Subjects: chemical sensing; chipless RFID; Gases; Heat; Internet of Things; Low concentrations; microwave sensor; Monitoring; Nanoparticles; Nitrogen dioxide; Radio frequency identification; Radio-tagging; Room temperature; Sensors; Spectrum analysis; Temperature; Tin dioxide; Tin oxide; Tin oxides
• ISSN: 2227-9040; 2227-9040
• DOI: 10.3390/chemosensors11070408

NO2 is an important environmental pollutant and is harmful to human health even at very low concentrations. In this paper, we propose a novel chipless RFID sensor able to work at room temperature and to detect sub-ppm concentration of NO2 in the environment. The sensor is made of a metallic resonator covered with NO2-sensitive tin oxide and works by monitoring both the frequency and the intensity of the output signal. The experimental measurements show a fast response (a few minutes) but a very slow recovery. The sensor could therefore be used for non-continuous threshold monitoring. However, we also demonstrated that the recovery can be strongly accelerated upon exposure to a UV source. This opens the way to the reuse of the sensor, which can be easily regenerated after prolonged exposure and recycled several times.