Oxygen-Vacancy-Rich SnO₂ Nanoparticles Based Ultralow-Power MEMS Sensor for Nitrogen Dioxide Detection

The development of highly sensitive and ultralow-power NO2 sensors is crucial for real-time NO2 monitoring. This study synthesizes tiny SnO2 nanoparticles with enriched oxygen vacancies for use in microelectromechanical system (MEMS) gas sensors, enabling ppb-level NO2 detection at reduced operating temperatures. PVP was used to adjust the particle size and surface oxygen vacancies in the hydrothermal method. The gas sensing performance shows that the 0.75 g PVP-SnO2 exhibited the highest response of 14.7 to 500 ppb NO2 at a low operating temperature of 102 °C, which is 3.2 times higher than that of the 0.00 g PVP-SnO2 sensor under the same conditions. Compared to similar studies, this sensor achieved a high response value and ultralow power consumption of 8.4 mW. The improvement in performance is mainly attributed to N doping and the abundance of oxygen vacancies. This research presents a promising strategy for the development of high-performance, low-energy, real-time NO2 gas sensors.