Oxygen-Vacancy-RichSnO₂ NanoparticlesBased 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.