Acetone Sensing Properties and Mechanism of SnO2 Thick-Films

Abstract

In the present work, we investigated the acetone sensing characteristics and mechanism of SnO2 thick-films through experiments and DFT calculations. SnO2 thick film annealed at 600 °C could sensitively detect acetone vapors. At the optimum operating temperature of 180 °C, the responses of the SnO2 sensor were 3.33, 3.94, 5.04, and 7.27 for 1, 3, 5, and 10 ppm acetone, respectively. The DFT calculation results show that the acetone molecule can be adsorbed on the five-fold-coordinated Sn and oxygen vacancy (VO) sites with O-down, with electrons transferring from acetone to the SnO2 (110) surface. The acetone molecule acts as a donor in these modes, which can explain why the resistance of SnO2 or n-type metal oxides decreased after the acetone molecules were introduced into the system. Molecular dynamics calculations show that acetone does not convert to other products during the simulation.

Surface Structure Engineering of Nanosheet-Assembled NiFe2O4 Fluffy Flowers for Gas Sensing

“…The reaction with the pre-absorbed oxygen species will release the captured electrons back to the gas-sensing materials, increasing the resistance. Further, the direct adsorption will be accompanied by a charge transfer from the ethanol molecules to the surface, increasing the resistance of p-type semiconductor materials [ 43 , 44 , 45 ].…”

Sensing and Delineating Mixed-VOC Composition in Air Using a Single Metal-Oxide Sensor

“…It is found that the resistance values in the presence of a second VOC (9.4 to 17.0 kΩ) were close to the values previously presented for single acetone (in the range of 10.1 to 15.2 kΩ, for the comparable range of 3 to 9 μL acetone), which signifies that acetone has a dominant effect on MOx sensor resistance. As such, it is again suggested that acetone is more likely to attach to the sensor compared to the other two compounds [18]. The relation between the combination of ethanol and n-hexane and resistance values is plotted and illustrated in Figure S11, and it is shown that the resistance values (15.3 to 25.3 kΩ) lean towards the single ethanol condition (16.7 to 25.7 kΩ).…”

“…For instance, it is plausible that acetone is likely to interact more strongly with the SnO2-based sensor. This could be explained by density functional theory calculations that show that acetone molecules act as donors to transfer electrons and can be adsorbed on Sn and oxygen vacancy sites [18]. Given that the resistance values of these three compounds range differently, this behavior is posed to be useful for identifying and quantifying the VOC composition more efficiently, as will be detailed in the model development (Section 3.4).…”

Sensing and Delineating Mixed-VOC Composition in the Air Using a Single Metal Oxide Sensor

“…It is found that the resistance values in the presence of a second VOC (9.4 to 17.0 kΩ) were close to the values previously presented for single acetone (in the range of 10.1 to 15.2 kΩ, for the comparable range of 3 to 9 µL acetone), which signifies that acetone has a dominant effect on MOx sensor resistance. Therefore, it is again suggested that acetone is more likely to attach to the sensor, compared to the other two compounds [31]. The relation between the combination of ethanol and n-hexane and resistance values is plotted and illustrated in Figure S11, and it is shown that the resistance values (15.3 to 25.3 kΩ) lean towards the single ethanol condition (16.7 to 25.7 kΩ).…”

“…For instance, it is plausible that acetone is likely to interact more strongly with the SnO 2 -based sensor. This could be explained by density functional theory calculations that show that acetone molecules act as donors to transfer electrons and can be adsorbed on Sn and oxygen vacancy sites [31]. Given that the resistance values of these three compounds range differently, this behavior is posed to be useful for identifying and quantifying the VOC composition more efficiently, as will be detailed in the model development (Section 3.4).…”