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

Abstract

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.

Applications of Chipless RFID Humidity Sensors to Smart Packaging Solutions

“…The geometry of the metallic structure was that of a square electric field-coupled (ELC) resonator [21,22] with a lateral dimension of 20 mm and was realized by microlithography and chemical etching. The geometry of the sensing structure was simulated and described in detail in [21,23], and it is schematically reported in Figure 1.…”

“…The geometry of the metallic structure was that of a square electric fieldcoupled (ELC) resonator [21,22] with a lateral dimension of 20 mm and was realized by microlithography and chemical etching. The geometry of the sensing structure was simulated and described in detail in [21,23], and it is schematically reported in Figure 1. The measurements were performed on four samples with four different distances between the metallic surface and the Nafion membrane, namely 0 (contact), 150, 400 and 800 µm.…”

Effect of temperature on the reaction of pristine and Au-doped SnO2 pyramid clusters with H2: A transition state theory study

“…(∆G= -1.250 eV). (11) In the above two equations, ∆G is the Gibbs free energy of the reaction. The negative value of ∆G is an indication that the reaction is spontaneous.…”

“…Tin dioxide is one of the most preferred materials in gas sensing [7,8] . SnO2 has been used to detect gases such as NH3 [9] , CO [10] , and NO2 [11] . One of the reasons why tin dioxide is a suitable gas sensor is the high number of oxygen vacancies at its surface [12] .…”