High-Sensitivity NO2 Gas Sensor Based on PbS Quantum Dots with WO3 Nanoparticle Catalytic Layer

다국어 초록 (Multilingual Abstract)

With the rapid pace of industrial development intensifying air pollution and greenhouse gas emissions, the resultingacceleration of global warming has increased the need for advanced technologies to mitigate these effects. Among various greenhousegases, nitrogen dioxide (NO2), primarily emitted from automobile exhaust and industrial processes, is recognized as a significantcontributor to global warming. Although semiconductor-type NO2 gas sensors based on metal oxides, such as SnO2 and ZnO, havebeen extensively investigated, they face challenges, including high fabrication costs, high power consumption due to elevated operatingtemperatures, and poor gas selectivity, which hinder accurate NO2 detection. Meanwhile, PbS quantum dots (QDs)-based gas sensorshave recently attracted attention for their high selectivity toward NO2 even at low operating temperatures. However, compared toconventional metal oxide-based sensors, their sensitivity, detection limit, and response speed still require significant improvement. Toovercome these limitations, this study introduces WO3 nanoparticles as catalysts to enhance the sensitivity and response speed of PbSQDs-based NO2 sensors. The optimized sensor, fabricated via screen printing, accurately detected NO2 gas concentrations ranging from1 ppm to 200 ppb, with a resolution of 200 ppb at room temperature. Furthermore, the developed sensor exhibited approximately 3.25times higher sensitivity and 18.7% faster response speed compared with the sensor without WO3 catalysts.